GEnetics - leadership

7/18/2019 GEnetics - leadership

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Copyright 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 10 and 51

Fetal Development and Genetics

Care of a child with a Genetic Disorder


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Key Terms !llele

"lastocyst

#uctus $enosus #uctus arteriosus

%mryonic 'tage

(ertili)ation

(etal stage

(oramen *$ale

+ene


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Key Terms

,norn errors o- .etaolism

+enotype .utation

Phenotype

Placenta

Preembryonic Stage

Homozygous

Heterozygous


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Key Terms

osaicism

onosomies orula

!risomies

!risomy "# !urner$s Syndrome

Fragile %


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Stages of Fetal Development

/reemryonic stage -ertili)ation through 2n week

(ertili)ation clea$age morula

"lastocyst an tropholast 4"o5 10617

,mplantation

%mryonic stage en o- 2n week through 8th week

"asic structures o- ma9or oy organs an maine5ternal -eatures 4:ale 10617

(etal stage en o- the 8th week until irth 4:ale 10617


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7/70Copyright 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins

Embryonic Layers

%ctoerm -orms the central ner$ous system; specialsenses; skin an glans

.esoerm -orms skeletal; urinary; circulatory; anreproucti$e organs

%noerm -orms respiratory system; li$er; pancreas; an

igesti$e system



Fnctions of the !lacenta

'er$ing as the inter-ace etween the mother an -etus

.aking hormones to control the physiology o- the mother /rotecting the -etus -rom immune attack y the mother



"ormones !rodced by the !lacenta

hCG

Human placental lactogen &hP'( or humanchoronic somatomammotropin &hCS(

)strogen

Progesterone

*ela+in



#mbilical Cord

Formed from the amnion

'ifeline from the mother to the growing embryo Contains one large vein and two small arteries

,harton$s -elly surrounds the vein and arteries toprevent compression

.t term/ the average umbilical cord is "" inches longand about # inch wide



$ole of %mniotic Flid

Helps maintain a constant oy temperature -or the -etus

/ermits symmetric growth an e$elopment Cushions the -etus -rom trauma

!llows the umilical cor to e relati$ely -ree o-compression

/romotes -etal mo$ement to enhance musculoskeletale$elopment



Fetal Circlation

0lood from the placenta to and through the fetusand then bac1 to placenta &see Figure #234(

!hree shunts during fetal life5

6 Ductus venosus5 connects the umbilical vein tothe inferior vena cava

6 Ductus arteriosus5 connects the main pulmonary

artery to the aorta

6 Foramen ovale5 anatomic opening between theright and left atrium



Fetal Circlation



&nheritance +enes ini$iual units o- hereity o- all traits

*rgani)e into long segments o- eo5yrionucleic aci4#=!7 that occupies a speci-ic location on a chromosome

#etermination o- a particular characteristicin an organism physical an mental characteristics o-humans

! chromosome long; continuous stran o- #=! carryinggenetic in-ormation

Karyotype pictorial analysis o- numer; -orm; an si)e o-chromosomes



Karyotype

Pictorial analysis of number/ form/ and size of anindividual$s chromosomes

Commonly uses white blood cells and fetal cells inamniotic fluid

Chromosomes are numbered from largest to

smallest/ # to ""/ with se+ chromosomes designatedby % and 7



Karyotype



!atterns of &nheritance

.enelian or .onogenic #isorers

!utosomal #ominant ,nheritance

!utosomal ?linke ,nheritance

>?linke ?linke #ominant ,nheritance

.ulti-actorial #isorers

=ontraitional ,nheritance



%tosomal Dominant &nheritance


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%tosomal Dominant 'enetic Disorders

8eurofibromatosis

Huntington disease

.chondroplasia

Polycystic 1idney disease


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%tosomal $ecessive &nheritance


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%tosomal $ecessive 'enetic Disorders

Cystic fibrosis

Phenyl1etonuria

!ay9Sachs

Sic1le cell disease


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()lin*ed $ecessive &nheritance


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()Lin*ed $ecessive 'enetic Disorders

Hemophilia

Color blindness

Duchenne muscular dystrophy


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()lin*ed Dominant &nheritance


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Fragile ( Syndrome


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+ehavioral !roblems %ssociated ,ithFragile ( Syndrome

.ttention deficits

Hand flapping and biting

Hyperactivity

Shyness and social isolation

'ow self9esteem

Gaze aversion


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-ltifactorial 'enetic Disorders

Cleft lip and cleft palate

Spina bifida

Pyloric stenosis

Clubfoot

Congenital hip dysplasia

Cardiac defects


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Cleft lip and Cleft palate


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Clbfoot


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!yloric stenosis


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.estion

:s the following statement !rue or False;

ales are more commonly affected by %9lin1edrecessive disorders3

a3 !rue

b3 False


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%ns/er

a6 :rue

.ost >?linke isorers emonstrate a recessi$e pattern o-inheritance; an males are more commonly a--ecteecause a male has only one > chromosome an all thegenes on his > chromosome will e e5presse6


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Chromosomal %bnormalities !normalities o- Chromosome =umer

.onosomies trisomies

/olyploiy

!normalities o- Chromosome 'tructure

#eletions

,n$ersions

:ranslocations

'e5 Chromosome !normalities


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Types of Chromosomal %bnormalities

Structural abnormalities

6 Cri du chat syndrome6 Fragile % syndrome

Se+ chromosome abnormalities

6 !urner syndrome

6


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rsing $oles and $esponsibilities 0eginning the preconception counseling process and

referring for further genetic information

!a1ing a family history

Scheduling genetic testing

)+plaining the purposes/ ris1s=benefits of allscreening and diagnostic tests &see 'aboratory and

Diagnostic !ests #23#(

.nswering >uestions and addressing concerns


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rsing $oles and $esponsibilitiescont2d34

Discussing costs/ benefits/ and ris1s of using healthinsurance/ and potential ris1s of discrimination

*ecognizing ethical/ legal/ and social issues

Safeguarding privacy and confidentiality

onitoring emotional reactions after receivinginformation

Providing emotional support

*eferring to appropriate support groups


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Significant Findings in -edical "istory of aChild ,ith a 'enetic Disorder

aternal age older than ?@ years or paternal age older than @2

*epeated premature births/ breech delivery


.bnormalities found on ultrasound or in prenatal bloodscreening tests

.mniotic fluid abnormalities

ultiple births

)+posure to medications and 1nown teratogens

Decreased fetal movement


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Do/ns Syndrome


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Trisomy 1 Do/n Syndrome4

Cause

6 Presence of all or part of an e+tra "#st chromosome

Characteristics

6 Some degree of intellectual disability

6 Characteristic facial features

6 Ather health problems &e3g3/ cardiac defects/ visualand hearing impairment/ intestinal malformations/and an increased susceptibility to infections(


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Trisomy 1Do/n Syndrome4

D%5 Aften d+ prenatally with prenatal screening e+ams

a(.minocentisis

b(Chorionic Billi Sampling

c(!riple=>uadruple screen

:f not d+ prenatally common physical characteristics aid

in the d+ within the first few days of life 3 S)) 0A% @#3?


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Laboratory and Diagnostic Tests for Do/nSyndrome

)chocardiogram5 to detect cardiac defects

Bision and hearing screening5 to detect vision andhearing impairments

!hyroid hormone level5 to detect thyroid disease

Cervical radiographs5 to assess for atlantoa+ial instability

ltrasound5 to assess for gastrointestinal malformations


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Do/n Syndrome "ealth Care 'idelines


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.dapted from .merican .cademy of Pediatrics/http5==aappolicy3aappublications3org=cgi=content=full=pediatrics#2E="="


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Trner2s Syndrome


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!hysical Characteristics of TrnerSyndrome

,ebbed nec1

Short stature

'ow posterior hairline

,ide9spaced nipples

)dema of the hands and feet

.menorrhea

8o development of secondary se+ characteristics

Sterility

Perceptual and social s1ill difficulties


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rsing -anagement

Support Family

8eed to understand that short stature and infertilityare li1ely3

:ntellectual disability is unli1ely/ but some learningdisabilities may be present3

)mphasize that with medical supervision and support/ girlswith !urner syndrome may lead healthy satisfying lives3

!urner Syndrome Society of the nited States


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&nborn Errors of -etabolism and%ssociated 6dor

.dapted from *ezvani/ :3 &"22E(3 .n approach to inborn errors of metabolism3 :n *3 3


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&nborn Errors of -etabolism

!K#9 deficiency in a liver enzyme leading to the inability toprocess the essential amino acid phenylalanine properly3!he accumulation of this amino acid leads to brain damageunless P


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!K#

anagement 6 low pheylalanine diet which is found

mostly in protein containing foods such as meat andmil1& including breast mil1 and formula(


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'alactosemia

Deficiency in the liver enzyme needed to convertgalactose/ the brea1down product of lactose/ which is

commonly found in dairy products/ into glucose3Galactose accumulation leads to damage to vital organs3

:ncidence5 less than # in @2/222

Clinical manifestations5 8o symptoms at birth3 :f

undiagnosed/ 80 will have -aundice/ diarrhea andvomiting and will not gain weight3 :f untreated can leadto liver disease/ blindness/ severe intellectual disabilityand death3


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'alactosemia

anagement9 :ngestion of galactose can produce sepsisin the affected child therefore/ septic wor19up and

antibiotics may be necessary in a child if galactosein-ection has occurred3

)limination of galactose and lactose from the diet is theonly treatment3 !herefore/ mil1 and dairy products will beeliminated for life3


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.estion

!he nurse is assessing a child for a genetic disorder andnotes that a musty odor emanates from the child3 ,hat

disorder would the nurse suspect;a3 phenyl1etonuria

b3 maple syrup urine disease

c3 tyrosinemia

d3 trimethylaminuria


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%ns/er

a3 phenyl1etonuria3 . musty odor emanating from thechild is associated with phenyl1etonuria3

*ationale5 . maple syrup odor is associated with maplesyrup urine disease/ a cabbage9li1e odor is associatedwith tyrosinemia/ and a rotting fish smell is associatedwith trimethylaminuria3


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$evie/

.fter teaching a group of students about fertilization/ theinstructor determines that the teaching was successful

when the group identifies which as the usual site offertilization;

a3 Fundus of the uterus

b3 )ndometrium of the uterus

c3 Distal portion of fallopian tube

d3 Follicular tissue of the ovary


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$evie/

!he correct response to this >uestion is C/ because scientistshave determined that conception=fertilization occurs in theupper portion of the fallopian tube3 . is an incorrect response

because this is where implantation ta1es place afterfertilization has occurred3 0 is an incorrect response becausethis describes the inner lining of the uterus/ whereimplantation ta1es place not where fertilization of the ovumand sperm occur3 D is an incorrect response because the spermdoes not travel outside the fallopian tube to the ovary/ butrather meets the ovum for purposes of fertilization in thefallopian tube


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$evie/

. client comes to the clinic for pregnancy testing3 !henurse e+plains that the test detects the presence of

which hormone; a3 hP'

b3 hCG

c3 FSH

d3 !SH


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$evie/

09 hCG


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$evie/

!he nurse is counseling a couple/ one of whom is affectedby an autosomal dominant disorder3 !hey e+press

concerns about the ris1 of transmitting the disorder3 ,hatis the best response by the nurse regarding the ris1 thattheir baby may have for the disease;

a3 K7ou have a one in four &"@L( chance3M

b3 K!he ris1 is #"3@L/ or a one in eight chance3M c3 K!he chance is #22L3M

d3 K7our ris1 is @2L/ or a one in two chance3M


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$evie/

!he correct response is D3 .utosomal dominantinheritance occurs when a single gene in the

heterozygous state is capable of producing thephenotype3 !he affected person generally has an affectedparent and an affected person generally has a @2Lchance of passing the abnormal gene to each of his orher children


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$evie/

. nurse is wor1ing in a women$s health clinic3 Geneticcounseling would be most appropriate for the womanwho5

a3 ust had her first miscarriage at #2 wee1s

b3 :s ?2 years old and planning to conceive

c3 Has a history that reveals a close relative with Down

syndrome

d3 :s #I wee1s pregnant with a normal triple screenresult


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$evie/

!he correct response is C3 !he family history plays acritical role in identifying genetic disorders3 . history of aprevious child/ parents or close relative with an inheriteddisease/ congenital abnormalities/ metabolic disorders/developmental disorders or choromosomal abnormalitiescan indicate an increased ris1 of genetic disorders/therefore referral to genetic counseling is appropriate3


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$evie/

. child born with a single transverse palmar crease/ ashort nec1 with e+cessive s1in at the nape/ a depressednasal bridge/ and cardiac defects is most li1ely to havewhich autosomal abnormality;

a3 !risomy "#

b3 !risomy #I

c3 !risomy #

d3 !risomy #?


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$evie/

!he correct response is a. !hese are some of thecharacteristics of trisomy "# &Down syndrome(3 !risomy"# is also associated with some degree of mentalretardation and other health problems such as cardiacdefects/ visual and hearing impairment/ intestinalmalformations/ and an increased susceptibility toinfections3


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$evie/

!he nurse is caring for a child with !urner syndromeadmitted to the unit for treatment of a 1idney infection3,hat characteristics associated with this syndrome maythe nurse e+pect to find upon assessment;

a3 icrocephaly/ polydactyly

b3 'ow9set ears/ cleft lip

c3 Short stature/ webbed nec1

d3 Gynecomastia/ taller than average


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$evie/

!he correct response is c3 . child with !urner syndromepresents with characteristic features/ such as shortstature and a webbed nec13 .lso seen in children withthis syndrome are a low posterior hairline/ wide9spacednipples/ edema of the hands and feet/ amenorrhea/ nodevelopment of secondary se+ characteristics/ sterility/and perceptual and social s1ill difficulties3 Gynecomastiaand taller9than9average height are characteristics seen in

children with


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