Prader Willi Syndrome

Hiba Nasir1248129

Genetics Presentation

Brief introduction

• Rare• Developmental disability• 15th chromosome • hypothalamus doesn't work properly• Key feature: hunger games. • Not INHERITED disease – Only 1%

Genetics

• Lack of 7 active genes on chromosome 15• (15q11-q13)• Genes normally active on paternal

chromosome.

•70%•Patern

al 15, PWS region deleted/missing

Paternal deletion •25%-

28% •Both

copies from mother

Maternal uniparental

disomy

•2%•Genes

are present but do not work.

•Inherited

Imprinting defect

History

• 1956• Andrea Prader, Heinrich Willi, Alexis Labhart.• Also called: Prader Labhart Willi syndrome.

Prevalence

• 1 in 10,000 to 30,000 people worldwide.• Not racial- both sexes

Characteristics

• Dysfunction of hypothalamus• Responsible for functions like: – Hunger, temperature and pain regulation, puberty,

emotions, and fertility.

• Unclear how genetic abnormality leads to hypothalamic dysfunction.

Symptoms

First stage (hypotonia) Hypotonic , low muscle

tone. Weak cry and a poor suck

reflex are typical. Low levels of GH Physical abnormalities:

narrow forehead, almond-shaped eyes, triangular mouth, short stature, small hands and feet

Second stage (hyperphagia) An unregulated appetite. Most common 2-6 years. Individuals with PWS lack

normal hunger and satiety cues.

M.R of persons with PWS is lower than normal.

Leads to morbid obesity Low sex hormone levels

(hypogonadism)

More symptoms o Behavioral problems, such as stubbornness or temper

tantrums

o Delayed motor skills and speech, not sporty.

o Cognitive problems, ranging from near normal intelligence to mild mental retardation; learning disabilities are common

o Repetitive thoughts and verbalizations

o Collecting and hoarding of possession.

Facts

• It is a SPECTRUM DISORDER • Mental strengths • Normal lifespan • Diabetes and Obsessive Compulsive Disorder• Depression is common

Diagnosis• FISH (fluorescence in situ hybridization)

Specific DNA sequences on chromosomes.

High degree of sequence similarity.

Fluorescence microscopy can be used to find out where the fluorescent probe bound to the chromosomes.

FISH is often used for finding specific features in DNA for use in genetic counseling, medicine, and species identification.

FISH can also be used to detect and localize specific mRNAs within tissue samples.

In this context, it can help define the spatial-temporal patterns of gene expression within cells and tissues.

DNA Methylation

Treatment

• Human growth hormone therapy• Physical therapy• Behavioral therapy• Medications • Sex hormone treatments• Diet control • Speech therapy

Life expectancy

• High • Sufferers are expected to live a normal healthy

life

Hope for the future

• More research • Focus on obesity • Hope today- for a cure tomorrow