GENETIC DISORDERS

Question 1

DOWN SYNDROME

occurrence rate, chromosome, risk factors, findings and other manifestations that may occur

Answer 1

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

Question 2

XXY syndrome and phenotypical manifestations

Answer 2

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

Question 3

XO Karyotype

Answer 3

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

Question 4

Marfan syndrome

Answer 4

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)

Question 5

Tay-Sachs disease

Answer 5

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

Question 6

DiGoerge (Velocardiofacial) syndrome

Answer 6

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