Trinucleotide Repeat Disorders Flashcards
Which genetic defect is commonly associated with anticipation?
Trinucleotide repeat defects.
At which point does the fragile X syndrome become a disorder?
If there are more than 230 copies of the CGG trinucleotide repeat on the X chromosome.
What physical changes occur from fragile X syndrome?
Long face, Large mandible, everted ears and enlarged testes.
Huntingtons disease is a result of what?
A trinucleotide repeat of CAG involving chromosome 4
At what repeat level does huntingtons become severe?
Affected indiviuals have more than 36 compies of CAG repeats on chromosome 4.
Chorea, involuntary movements, and oculomotor abnormalities are all signs of what disease?
Huntingtons disease diagnosed by genetic testing.
What is Edwards Syndrome?
Trisomy 18 causing severe psychomotor and growth retardation with microcephaly, clenched fingers.
Club Foot/Rocker bottom foot
What is Patau Syndrome?
Trisomy 13
Severe intelectual disabilities
Cleft lip
Very small/poorly developed eyes.
Only 5-10 percent live to survive past first year.
What is Turners syndrome?
Complete or partial X chromosome monosomy in phenotypic female.
What is the frequency of turners syndrome?
1/5000
What is the clinical hallmark of turners syndrome?
Sexual infantilism with primary amenorrhea and sterility with most cases not being discovered until absence of menarche.
Very short women
Short Webbed neck
What occurs genetically in Klienfelters syndrome?
Extra X chromosome displaying the XXY karyotype.
What is the occurence for kleinfelters syndrome?
1/1000 in male newborns.
Prader Willis and Angelman syndrome both occur on what chromosome?
Chromosome 15!
What are the clinical findings of Prader-Willi syndrome?
Metal retardation, short stature, hypotonia at birth.
Obesity tendency to overeat and hypogonadism.
