GENETIC DISORDERS Flashcards
DOWN SYNDROME
occurrence rate, chromosome, risk factors, findings and other manifestations that may occur
presence of a third #21 chromosome. Increased maternal/ paternal age increases risk. Typical findings:
Microcephaly, abnormal head shape, flattened nose, eyes set wider (hypertelorism= widely separated eyes) due to flattened nose, protruding tongue, inner epicentral folds, upward slanting eyes, short board hand/ fingers; single palmar crease, delayed growth/development, hypotonia, Brushfield spots (star of iris of the eye)
Other manifestations: Seizures, congenital heart disease, endocrine abnormalities (thyroid ,diabetes), esophageal/ duodenal atresia, hearing/vision impairment, obesity, leukemia, early dementia
XXY syndrome and phenotypical manifestations
Klinefelter’s syndrome, extra X chromosome in males. Appears normal at birth, presenting in puberty. May present initially as infertility. Most common cause of hypogonadism and infertility in men.
Manifestations: Tall stature, transverse crease, abnormal body proportions, UNDEVELOPED SECONDARY SEXUAL CHARACTERISITCS, gynecomastia, learning disability, personality impairment
XO Karyotype
Turners syndrome. Most common female chromosome abnormality. Typical findings include lymphedema (puffy), webbed neck, low hairline, learning disabilities, lack of secondary sexual characteristics, shield shaped chest/ widely spaced nipples, head/neck abnormalities, HTN, BICUSPID AORTIC VALVE/ COARCTATION OF THE AORTA
Marfan syndrome
inherited connective tissue disorder affecting skeletal, caridac, and ophthalmic body systems. Presentation: Tall stature, arm span exceeds height, thin extremities and fingers, long narrow face, pectus carinatum or excavatym, hyperextension of joints, genu recurvatum, kyphoscoliosis, high arched, narrow palate, cardiovascular- aortic regurgitation, mitral valve prolapse, aortic aneurysm. eyes- octopi lentos (displacement or palpostiion of the crystalline lens of the eye) iridodnesis (vibration)
Tay-Sachs disease
Ashkenazi jewish population. Normal at birth, deterioration between 3-6 months of age. Progession- decreased muscle tone, cherry red macula (is diagnostic) listlessness, blindness, deafness, SZ, dementia, vegetative, death
DiGoerge (Velocardiofacial) syndrome
congenital defect of the parathyroid glands, thymus, and conotruncal region of the heart. infections, abnormal facies, congenital heart defects (aortic arch abnormalities- do pulse ox on extremities), hypoparathyroidism with hypocalcemia and seizures, cognitive and behavioral problems. Signifiacnt morbidity and mortality
