study d eport - Triple-X syndroom

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Genetics of SexChromosome Trisomy:Professor Pat Jacobs

Pat Jacobs, Professor of Human Genetics at theWessex Regional Genetics Laboratory, toldfamilies that they owed both the study day andthe Sex Chromosome Trisomy study to the factthat she had shared a long taxi ride with HelenClements, who runs the UK Triple X supportgroup, and her daughter Megan and realised

Families with a daughter with Triple X syndrome – a single extra X chromosome –met experts and researchers at a study day in Oxford, UK in September 2007.They heard what is already known from research conducted on girls and women with Triple X who were recruited in the 1960s and they were invited to tellresearchers from the Sex Chromosome Trisomy study group what they would like the new study, launched this summer in the UK, to focus on.The findings from thestudy day will help to sharpen the focus of the study, which is looking at behaviour and learning in girls and boys aged between 4 and 16 with Triple X, XYY and XXY(Klinefelter syndrome).

(Slide 1). By analogy with the fly Drosophila,scientists assumed that the blob was two Xchromosomes. However, in the early 1960s,Professor Jacobs looked at the chromosomesof a woman with Triple X and saw not one, buttwo blobs.What was then to be revealed wasthat when humans have two X chromosomesonly one is fully working and the second onecurls up on the edge of the cell to form a blob.That is true however many extra Xchromosomes a person has. So a single blobwas the second of two X chromosomes and anucleus without a blob had only one Xchromosome.To discover how many Xchromosomes someone has, you count theblobs and add one.

Professor Jacobs then moved on to the sixnewborn studies that form the basis of almosteverything that is known about children and

adults with a sex chromosome trisomy.In the early 1960s, all babies born at sixcentres worldwide – in Denmark,Scotland, two centres in Canada andtwo in the US – had a blood sampletaken and their chromosomesanalysed. From a total of some 60,000babies it was found that each of thethree sex chromosome trisomies -Triple X syndrome, XYY and XXY -occurs at a rate of around 1:1000sex matched newborn babies. Butwhat has happened before birth?She reminded families that not allbabies are born alive, some miscarry(15-25 per cent of clinicallyrecognisable pregnancies) and avery much smaller number (aroundone per cent) are stillborn. Lookingat the three groups of babies with

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how little we in Britain were doing for bothgirls with Triple X and boys with XYY (an extraY chromosome).

What is that blob?Professor Jacobs then took families back to the1950s, before chromosomes were identified,when an astute microscopist noticed a blob inthe nucleus of cells in females but not in males

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why so few of them have been picked up anddiagnosed.This is one thing a new study ofXXX girls recognised at prenatal diagnosisshould be able to show.

Growth and Development,Puberty and Fertility:Professor Gary Butler

Gary Butler, now Professor of Paediatrics(Growth and Development) at the Universityof Reading, explained the origins of his interestin children’s growth as a young paediatricianand his pleasure at the opportunity to workwith Dr Shirley Ratcliffe on following up theEdinburgh newborn study, which included 16girls with Triple X (slide 3).The study showedthat chromosome variations are far from rare,affecting one person in 150 and sexchromosome variations affecting one in 250.Professor Butler pointed out that baby girlswith Triple X have no distinctive features ornecessary health problems that would promptdiagnosis at birth. ‘There is no particularregularly occurring problem that would mean


a sex chromosome trisomy, she found quitedifferent rates of pregnancy loss – of babieswith XXY (Klinefelter syndrome), half are lost;of those with XYY, none are lost; and of thosewith Triple X, 75-80 per cent are born, while15-20 per cent are lost. No-one knows whythese differences occur but one might wonderwhether the extra Y chromosome in babieswith XYY is in some way protective inpregnancy.

Need for new studiesProfessor Jacobs admitted that she wasseriously concerned about how little we knowabout children and adults with an extra sexchromosome. It is vital to start with anunselected population, not those who have hadtheir chromosomes studied after birth becausethey have shown some problem of health ordevelopment.Yet it would not be possible torepeat the newborn study method of the1960s, as it is no longer ethically acceptable toanalyse the chromosomes of babies whoappear entirely healthy. Instead, it would bepossible today to capture a new unselected

population – those babies whosemothers are offered prenataldiagnosis due to increasedmaternal age, because they areolder mothers.

As 95 per cent of babies withTriple X get their extra Xchromosome from their mother,you would expect to see manymore Triple Xs in this group, anda rather smaller increase in boyswith XXY, as only half of themget their extra X chromosomefrom their mother, while theothers get it from their father.Looking at recent reports ofbabies with an extra sex

chromosome, Professor Jacobs found theincrease she expected in babies with Triple Xbut a startling rise of 60 per cent since the1960s in babies with Klinefelter syndrome.Thisremains unexplained but it is possible to testthe hypothesis that the rise is due to anincrease in babies with Klinefelter caused by anextra X chromosome from their father, whichin turn could be linked with the well-publicisedfall in the sperm count and rise in abnormalsperm.

How many girls with Triple X are diagnosed?Professor Jacobs’ Wessex genetics laboratoryserves a population of almost 3 million, andTriple X occurs at a rate of 1:1,000 girls.Yet inWessex only 94 girls with Triple X are known,about seven per cent of the expected total(Slide 2). Most of these girls with Triple X – 43per cent in the Wessex sample – werediagnosed prenatally because they had an oldermother and others – 37 per cent – after theyshowed some degree of developmental delay.Very few – just 6 per cent – are diagnosedbecause of reproductive problems.What is notknown is how typical these 94 girls are and

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possible to make universal statements. He alsoaccepted that the Edinburgh girls showedgreater variability in height than the populationthey were compared with.

LearningThe tests used to assess learning andintelligence thirty years ago were fairly crude,Professor Butler told families. One test that isadmittedly crude but has stood the test of timeis the Wechsler Intelligence Score for Children(WISC), used to assess IQ.The range ofindividual girls’ scores on this test in theEdinburgh study was very wide but theiraverage was 93, compared with 111 for thecomparison population.WISC scores separatelanguage from ‘performance’ – problem-solvingand practical things – and the Edinburgh girlsshowed slightly more delay on the verbal sidethan in performance. All the girls in theEdinburgh study bar one had an IQ well withinthe normal range so what was showing herewas certainly not a learning disability but adifference in the learning process.

SchoolsBut how useful are intelligence tests andpsychology measures in terms of real life,Professor Butler wondered. All bar one girls inthe Edinburgh study went to a mainstreamschool, the other attended a special school. Inhalf the girls in mainstream education, schoolspicked up on their need for learning supportwith reading and/or maths and as the schoolshad not been alerted to the girls’ Triple X,Professor Butler saw this as evidence thatschools are doing their job and providingsupport on the basis of need. ‘This gives us faiththat even when it’s stretched, the educationsystem can and does recognise when childrenhave learning problems and can put in placethe necessary help,’ he maintained.

Nonetheless, he said that most girls expressedrelief when they could leave school. Perhaps


Slide 3 most girls grew entirely normally although oneor two were unusually tall.The pattern of

growth was the same for girls with XXand those with Triple X, with lots ofsmall growth spurts before a largegrowth spurt at puberty. However, in girlswith Triple X the growth spurts occurslightly later than in girls with XX and thepuberty growth spurt seems to occurabout six months later.

‘There is a very slight and subtle delay inthe growth process in girls with Triple X,’Professor Butler said.

Measurements at ages 3, 5, 7 and 9 showedthat throughout childhood girls’ legs growdisproportionately to their backs, so theyhave subtly longer legs, he said.Their headcircumference was also smaller than averageoverall, but ‘we are looking at very, verysubtle variations in growth,’ he said.

SurprisingOne family was surprised to hear that thestudy showed Triple X girls might be short andhad been told that they were more likely to betall.

Professor Butler agreed that the Denver studyshowed increased height and that two girls inthe Edinburgh study were surprisingly tall buthe suggested that information about heightmay be confused with Klinefelter syndrome,where boys with an extra X chromosome mayhave increased height. ‘An extra X doesn’tnecessarily mean tallness,’ he stressed. Hesuggested that differences may depend onwhich one of the three X chromosomes is notswitched off. If the fully active X chromosomecomes from the mother and the father’sgrowth genes are switched off, the girl might beshorter, but if the mother’s growth genes areswitched off, the girl might be taller. ProfessorButler admitted that the number of girlsfollowed up from the worldwide newbornstudies – 20-30 in all – is so tiny that it is not

that a paediatrician would automatically checkthe chromosomes. Usually there are noproblems and this may be one reason whyTriple X is rarely picked up at birth,’ he said.

GrowthDifferences in growth were subtle and onlyshowed up when you observed groups, ratherthan individuals, Professor Butler pointed out.The Edinburgh study showed that at birth, babygirls with Triple X were slightly lighter (3.04kgcompared with 3.36kg for girls with XX) andtwo centimetres shorter than the average forthe population. However, their mothers wereon average more than four centimetres shorterthan the mothers of the girls with XXchromosomes and this could account for theirsize at birth, although it was also possible thatthe extra X chromosome did have some effecton growth within the womb. In one of the USstudies (Denver, Colorado), the Triple X girlsgrew to be slightly taller than average but thiswas not seen in the Edinburgh study, where

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because of the differences in the learningprocess, they felt under pressure there.Threewent on to college to study mainly arts-relatedsubjects; others moved into practical careersincluding cooking, hairdressing and waitressingwhile others decided to be housewives. ‘It wasvery positive – all of them were able to moveon in ways they wanted to and contribute tosociety in very different ways,’ he concluded.

BehaviourIn terms of behaviour, girls did seem to havesomewhat more problems but the sorts ofdifficulties they experienced are found as wellin girls without any sex chromosome variation.So for example at the age of three, slightlymore girls had a difficulty with food or eating,some with soiling, others with being slightlyunderactive rather than hyperactive, some haddifficulties with concentration, others had foundproblems with making and keeping friends,others had issues with being unusuallydependent and in others tempers were morefrequent, perhaps because of frustration at notbeing able to understand. At a later age, moregirls had a referral to the child and adolescentpsychiatry team than the comparisonpopulation, but the referrals (depression, duelargely to family circumstances; drug abuse;obsessive-compulsive disorder) were not forunusual problems and whether they wererelated to the extra chromosome or not,no-one really knows.

Puberty and fertilityProfessor Butler was upbeat about puberty.Puberty occurs entirely normally, though thefirst signs of puberty (breast development), hesaid, might occur around 11 years, perhaps sixmonths later than the population norm andfirst periods at 13 to 14 years, a year or solater than in comparison girls.

The evidence around girls going on to havehealthy babies themselves is very thin, he said,in part because the girls in the originalnewborn studies are of an age when theymight still have children and in part because itis not considered ethical to examine thechromosomes of an apparently healthy, normalbaby. Certainly, the great majority of womenwith Triple X appear to have normal healthybabies but there is the possible suggestion froma review of the literature that 16 per cent mayhave a baby with a chromosome abnormalityalthough this figure is heightened by thetendency of doctors to report abnormal ratherthan normal findings. Overall, there have notyet been enough studies looking at pregnancyoutcomes for women with Triple X.

See also Is Triple X hereditary?

Getting the message outProfessor Butler ended with a plea to familiesand support groups to get out to the widerworld the overall very positive and upbeatmessage about outcomes for girls with Triple X.When a couple is given a Triple X diagnosis inpregnancy they may be counselled by ageneticist, a paediatrician or an obstetrician.Health professionals such as geneticists andpaediatricians who see families with a daughterwith Triple X are much more likely to bepositive in their counselling and present an

image of a child with whom there might be afew problems that can be coped with butotherwise is going to manage and contribute tosociety. Health professionals who have nopersonal experience of Triple X are more likelyto present an unnecessarily bleak picture andthis affects the termination rate.

QuestionsWhen do we tell our 10-year-old daughterthat she has Triple X and how?

This is a very important point that a lot ofparents ask about.With each child it’s differentand it depends on your circumstances. I suggestto families with a son with Klinefelter syndromethat they explain bit by bit according to thechild’s level of understanding. If a girl who isasking why she has had difficulty with speech,or why she needed help in school or perhapswhy she has seen a developmentalpaediatrician or an educational psychologist,you might tell her that since a test can help toexplain the reasons, one was carried out andTriple X was found. One point not to forget isthat every single one of us carries geneticvariations, some of which are identifiable andknown about while others are not.

One family pointed out that as the Triple Xdiagnosis is on their daughter’s medical records, ifthey take her to the doctor with something


Quote

❝When looking at girls with Triple X, there’s nothing to say that this is something thatalways occurs in all of them.The children don’t look different, their physique and mindfunctioning is within the normal range. Given as you look under the microscope and see awhole extra chromosome, a huge extra package of genetic material, if it was one of theother sets of chromosomes 1 to 22 there would be a massive effect and the vast majoritywould not even see the light of day. Even a little chromosome like 21 which causes Downsyndrome doesn’t have as much genetic information on it as the X chromosome and lookat the big difference it has on the child and its functioning compared with the Xchromosome.❞ GB


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incidental like a cold, the doctor mentions theTriple X. As soon as she’s old enough to go to thedoctor’s alone, she will discover about it.

At the age of 5, our daughter with Triple Xhas many holes in her teeth, quite unlikeher three brothers and sisters. Is this partof Triple X or not?

This question led to a show of hands: 14 out20 families had noted some sort of dentalproblem. One mother, the wife of a dentist, saidher husband had noticed that her daughter’steeth have a formation that is not hereditary.Helen Clements said that this was the subjectof a thread on the Yahoo group(groups.yahoo.com/group/raregeneticdisorders)and other problems described there includedpitting, poor enamel formation and the needfor fluoride coating to stop disintegration.Victoria Leggett said that in her literaturereview she had come across a paper whichsuggested that girls with Triple X have adifferent tooth structure with thicker but lessrobust enamel.

See Features of Triple X syndrome in Uniquefamilies

Are the nails also affected?

A small number of families reported that theirdaughters have flaky nails and other nailproblems such as biting.

Is Triple X hereditary?

Not as far as we know. In principle it should bebecause if you have an extra X chromosome,then in theory half your eggs will have 23chromosomes and half will have 24chromosomes.You would expect then that halfthe children would have Triple X or Klinefelter,depending on whether the egg is fertilised withan X-bearing or a Y-bearing sperm. But thisdoes not appear to be the case and we don’tknow why, unless it is that an egg that gets anextra X by this mechanism may not be viable.

We do not have good data on the children ofwomen with Triple X but the data we do havesuggest that it is not hereditary.

Helen Clements suggested that there is anecdotalevidence of a higher miscarriage rate amongwomen with Triple X, particularly those who havea mosaic form (some cell lines have an extra Xchromosome while others do not) but ProfessorJacobs said there is no hard evidence for this.

Should a woman with Triple X who isplanning a pregnancy have geneticcounselling beforehand or amniocentesisin the pregnancy?

Genetic counselling should be available andfamilies can refer themselves direct to clinicalgenetics or ask for a GP referral. Most peoplewould also say yes to an amniocentesis and if awoman with Triple X asked for amniocentesis,she should get it.The results of the triple testor other early pregnancy blood tests to assessthe risk of certain abnormalities in the baby donot help with sex chromosomes.

My daughter with Triple X was alsoexposed to sodium valproate before birthand also has hypermobility, bendy joints.

Bendy joints are quite common in children.There might be a subtly increased chance ofbendy joints but one difficulty when trying tocompile lists of features associated with agenetic condition is that many of the featuresoccur by chance and may not actually becaused by the condition.There are two mainreasons for bendy joints – one is that the jointsthemselves can be a bit loose or the musclesand tendons are stretchier or not so strong.Usually there is no one particular cause.

Do women with Triple X have an early menopause?

The questions to ask are if there is likely to bean early menopause, by how much and is itsignificant? If there are reduced numbers of


eggs in the ovary of a woman with Triple X orif there are more eggs that are likely to havethe extra X chromosome, then are some ofthose extra X eggs being sidelined? Is that areason for an early menopause?

And what do you mean by an earlymenopause? If the average age of themenopause in this country is 52 years, if itwere five years younger at 47, would that makea significant difference? It might make adifference if women are leaving it until later tohave children. Also, we know that after the ageof 37 in women with XX chromosomes, thenumber of eggs in the ovaries is reduced andthat’s one of the reasons why it’s more difficultto conceive after the age of 37. It might be thatthat age in women with Triple X may be earlierbecause of the reduced number of normal eggsin the ovaries. But we don’t know that and itwould have to be looked at in further studies.

Families’ questions were answered by Gary Butlerand Pat Jacobs

Family concernsFamilies formed two groups according totheir daughter’s age with families with aprimary school age or younger daughter inone group and those with a daughter ofsecondary school age or older in the secondgroup. Each group discussed issues aroundbehaviour, social skills, learning andcommunication including speech but as youwill see, their discussions ranged far wider.Here are the main issues that emerged.

Younger group: Everyone felt that theirdaughter had something in common with othergirls with Triple X. Some had slightlyemotionally immature behaviour or otherbehaviour issues relating to emotionalimmaturity, such as fighting or pinching. Girlsmight stand too close to other children whomight find that difficult. A low pain thresholdwas mentioned by many families as well asgrowing pains; many girls were woken at night


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with leg and growing pains. Some childrendisplayed very different behaviour dependingon their environment: children who behavedbadly at school were good at home and viceversa. Some children got very tired and thisaffected their behaviour. Some hadinappropriate or sexualised behaviour.Generally girls were felt to be quite naïve,trusting, impressionable and easily-led; youngergirls got upset easily but older children grewout of this. Almost all girls had some degree ofhypermobility or bendiness. Some had a degreeof clumsiness, with some difficulties withcoordination and balance; some familiessuggested horse-riding and ballet to help withbalance and coordination. Many children hadspeech therapy, experiences both good andbad; other therapies were physiotherapy andoccupational therapy. For speech, peoplerecommended that singing, repetition andthings with a beat worked well. Many parentssaid their girls didn’t like loud noises such asplanes going overhead or motorbikes.

A lot of families talked about their childrenbeing good with adults and younger or olderchildren but perhaps sometimes struggling withtheir own age group. Many families found thattime out was helpful for behaviour. On astatement of special needs: only one family gotone, most were turned down because theirchild’s special needs were not thought to merita statement so they did not get extra help atschool. On memory: some parents thought thattheir child had a poor short-term memory butan excellent long-term memory. A lot of thegirls were very good at reading but less goodat understanding what they had read. On lifeskills – crossing roads, going to shops alone –girls were able to do this but they didsometimes struggle to make decisions. Onteeth: a lot had dental problems in commonalthough this was a surprise to some families;lots had holes and fillings; a number hadcrossbite and other dental problems. Onsources of information and what people foundon the internet: the Yahoo support group

(groups.yahoo.com/group/raregeneticdisorders)was found to be very helpful as theinformation came from other parents, and wasgenerally very positive and realistic while someother information was quite scary andhorrifying. On girls’ strengths – some were verygood at accents or mimicry, others at art ormusic, and they were also very interested inhow things worked and in engineering.

Reported by Sarah Wynn, Unique

Older group: On school – some girls werequiet in school but chattier outside and athome. Most children were in mainstreamschool with support. Parents were concernedto make teachers more aware; they discussedhow good SENCOs (special educational needscoordinators) are and how good the routine isat school; one parent said her daughter’s schoolwas very organised, all the teachers knewabout the Triple X and that was a big help as allteachers could support her daughter.The lackof printed information makes it very difficult togo into school and explain, as girls may onlyshow the typical characteristics of Triple Xoutside school; sometimes teachers andauthorities don’t believe what parents tell themunless they have seen the behaviourthemselves. A few parents were turned downfor statements of special educational need; onewas approved. Generally there was not a lot ofsupport in school; one family lost their supportbetween two school years. One concern wasthat school statements are not beingadministered by the authorities.

On behaviour: girls didn’t like attentionfocused on themselves; some children had atemper and families used time out. Girls weresensitive and needed a sensitive approach. Onpersonal hygiene, some girls had to bereminded to carry out daily personal careroutines. However, this was not consistentthroughout the group. Some girls were quiteconscious of their appearance.

On social communication and skills: girls couldmake friends but might not understand the

complexities of relationships.They might takestatements like ‘You’re not my best friend anymore’ literally and find it difficult to cope.Parents might have to keep their daughters ona short leash where friendships wereconcerned, explaining the dangers of beingoverfriendly with other children, especially boys.Building confidence: there was a generalconsensus that girls with Triple X are slow tomature emotionally.Their confidence may beundermined if they can’t keep up with theirfriends. Children compared themselves withtheir siblings and where the siblings werebrighter, their daughter struggled to reach thesame level and that dented their confidence. Inone case, a child with no siblings did well.

On communicating: it was important to usesmall pieces of information and to breakinstructions down into small bits. Singing andrepetition were helpful. One girl picked upplaying the piano very well because it wasbroken down into small pieces, each practisedseparately.

On coordination: a lot of the children wereOK with gross motor skills but fine motor skillscould be a problem; occupational therapyhelped some; music helped too, as well as withfrustration.

On memory: a lot of girls had a very goodmemory for fine detail; some could rememberdirections when they had only visited a placeonce.There was a general interest in music.Short term memory could be slightly difficult.

Girls generally showed a sensitivity to loudnoises and strong smells and hypersensitivity todifferent textures. Children were used toroutine and struggled more with novelty orbreaking out of their routine.

From a show of hands to determine how thegirls were diagnosed, seven were diagnosedprenatally, of whom six mothers had anamniocentesis due to advanced maternal age.Three girls were diagnosed after birth.

Reported by Satnam Juttla, Unique


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Victoria Leggett, a researcher at theDepartment of Experimental Psychology inOxford, explained the background to thecurrent sex chromosome trisomy study. Manypublished studies are quite old. Some studies

contradict each other and many include onlyvery small numbers of girls with three Xchromosomes. Most studies focus on areas thatare problematic and fail to highlight thestrengths of girls with an extra X chromosome.

After finding that many girls had features in common, families had a ‘show of hands’ todetermine how commonly certain features occurred in their daughters with Triple X

Frequency of some features of Triple X Syndrome in Unique familiesFeature Number of girls

(total 20)

■ Co-ordination/Balance 14■ Leg pains 12■ Stomach pains 12■ Dental problems 14■ Small hands/feet 5■ Hypermobility/Bendiness 13■ Hypotonia/floppiness in trunk 10■ Stress reactions/Anxiety 13■ Sensitivity to external stimuli (noises, smells, textures, etc) 16■ Temper tantrums (not age appropriate) 7■ Naivety (emotionally immature behaviour) 15■ Low self esteem 10■ Speech/Language problems 15■ Word retention problem 15■ Poor short-term memory 17■ Good long-term memory 11■ Good attention to detail 5■ Poor personal hygiene (those aged 10 and over) 7/11■ Good at directions 5■ Good at music 13■ Good at art 10■ Good with younger children (those old enough to be able to determine) 14/14

Professor Kate Nation, Sarah Wynn (Unique) andVictoria Leggett.

The Sex Chromosome Trisomy study wants tolook at any difficulties that girls may have andwhat kind of effect they have on theirchildhood.They want to look at whatinformation is available on Triple X, what isneeded and how they can improve it.

The study is recruiting families with a daughteraged between 4 and 16 years, where possiblewith a sibling for comparison. 150 children willhave been prenatally diagnosed – 50 girls withXXX, 50 boys with XXY and 50 boys withXYY. In addition, from Unique, there will be 50 girls with XXX and 50 boys with XYY.The researchers will ask parents in a semi-structured interview questions about their child’s responses in different situations.They will ask about the environment and aboutthe impact of any difficulties the child may haveon others, such as on the mother.They will askparents to fill in questionnaires on socialinteractions, looking at emotional andbehavioural development, on difficulties withattention including hyperactivity, oncommunication skills (social communication andlanguage development), on fine and grossmotor skills and on health, as well as birth anddiagnosis. At this stage, the range of questions isvery broad because the researchers are not yetsure what they are going to find.

From reading research papers publishedalready, the researchers expect they may find

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particular difficulties in learning and inmovement (such as the flexibility mentioned byfamilies), and possibly some difficulties withinattention and behaviours.The environmentmay be particularly important with differentindividuals responding differently in differentenvironments.

Victoria explained that in this preliminary studythe parents will be interviewed but the childrenwill not be tested directly.This is because the150 children with a prenatal diagnosis may noteven know about their extra sex chromosomeyet. Any parents who want to know more canemail Victoria at [email protected] telephone 01865 271381.

Gaia Scerif, a lecturer in the Department ofExperimental Psychology in Oxford, is adevelopmental psychologist interested inattention and behaviour and memory in theclassroom.Together with all the members ofthe study team, she pointed out that althoughthe Sex Chromosome Trisomy study is apreliminary one and will hopefully lead on to amuch larger study, it is likely to be larger thanany other study of the sex chromosometrisomies published so far.The studiesconducted so far have been very general andlooked at differences in measures such as IQrather than the processes that might underliethese differences. Some evidence has suggestedthat some girls have difficulties with payingattention, with memory or in understandingcomplex language.Teasing those differencesapart may help in understanding why girlsmight have difficulties in understanding andfollowing complex instructions and planningcomplicated behaviour.


Ivan Foster, Professor Dorothy Bishop and Rosie Van Moppes.

Ivan Foster with Gaia Scerif.

The study team would also like to tease apartany differences in speaking, understanding andattention and to identify any strengths that girlswith Triple X have.The researchers need toknow about girls’ strengths and weaknesses andDr Scerif stressed that parents should let themknow if there are particular types of memoryand attention that they feel their girls are goodat or less good at.The team will be able totease different types of attention and memoryapart – such as sustained attention versusselective attention, long term versus short termmemory, visual memory in the environment,spatial memories, memorising routes, auditorymemories.These types of attention andmemory don’t always hang together in thesame child and the team will be able toexamine this in girls with Triple X.

In the first instance, the study team will only beasking parents about their experience but if ata later stage they do test the children, there aremany tests now available that can be used withvery young children who may not even betalking yet.

Dorothy Bishop, Professor ofDevelopmental Neuropsychology in theDepartment of Experimental Psychology atOxford, has an expert interest in language. Herparticular expertise is in children who haveknown learning difficulties and a SpecificLanguage Impairment where everything hasdeveloped normally except language. If a childdoes have problems with language, she isinterested in which aspects are affected andwhether anything can be gained from looking atit in the same sort of way as Specific LanguageImpairment and related disorders such asautistic disorders are looked at.

Professor Bishop explained briefly some of thecomplexities of language.The production ofspeech sounds can be a difficulty – it may benormal for a toddler to say pit instead of fish ordado instead of table but not for a 4-5-year-oldchild. It is not yet known whether this is aparticular problem for girls with Triple X.Similarly, some children have difficultydiscriminating between speech sounds.Youngbabies tend to discriminate better than olderbabies, children and adults who lose the abilityquite early on to distinguish between speechsounds that are not relevant to their ownlanguage. Again, it isn’t known whether this is aparticular problem for girls with Triple X.Typically developing children produce their firstwords around 12 months and from around 18months to 6 years acquire vocabulary at thephenomenal rate of nine new words a day,acquiring a vocabulary of around 16,000 wordsbetween age 1 and age 6. It’s not knownwhether this is a problem area in girls withTriple X or whether they acquire the samesort of words as other children. Putting wordstogether to form short phrases and addingendings to words (grammatical inflections) sothat events can be described (I walked) rather


than objects being labelled (fish, table) can bethe source of great difficulty for children with aspecific language impairment but again it isn’tknown if this is an area where girls with TripleX have particular difficulties. Some childrenhave difficulties because they understandlanguage literally or fail to take the context intoaccount. An example is a child being testedwho was asked by the researcher ‘Could youstand to do some more?’ and promptly stoodup.These are known as higher levelcomprehension skills or pragmatic languageskills and the researchers hope that thequestionnaires parents complete will showthem how far this type of comprehension is aproblem with their daughter.

‘Talking to parents about the sorts of thingsthat they have observed will give us a feel thatwe can then home in on and get a much moreprecise picture of the nature of the problemschildren have and indeed their strengths also.We want to get a better picture before werush in with tests that might not be totallyrelevant to the problems children have,’Professor Bishop concluded.

Photographs: HELEN CLEMENTS

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