Genetics Flashcards
Features of trisomy 18
Edwards syndrome. Weak cyry, single umbilical artery, micrognathia with small mouth and high arched palate, rocker bottom feetClenched hands wit overlapping digits, small palpebral fissures, prominent occiput, short sternum, and cardiac defects.
Features of trisomy 13
Patau syndrome. Microcephaly and sloping forehead, deafness, omphalocele, single umbilical artery, hypersensitivity to agents containing atropine and pilocarpineCutis aplasia, polydactyly, holoprosencephaly, cleft lip/palate, postaxial polydactyly, flexed and overlapping fingers, coloboma, and cardiac defects.
Tay sachs is deficiency in?
Beta hexosaminidase A
Features shared by tay sachs and niemann pick
Loss of motor milestones, hypotonia, feeding difficulties, and cherry red macula
Features that distinguish niemann pick from tay sacks
Hepatosplenomegaly, areflelexia
Feature that distinguishes tay sachs from niemann pick
Hyperreflexia
Galactocerebrosidase deficiency results in what kind of symptoms?
Crab disease, a rare autosomal recessive lysosomal storage disorder that presents early in infancy with dev regression, hypotonia, and areflexia.
Glucocerebrosidase deficiency results in what kind of symptoms?
Gaucher disease. Anemia, thrombocytopenia and hepatosplenomegaly.
Lysosomal hydrolase deficiency results in what kind of sx?
Hurler syndrome. Presents at age 6 mos-2 years with coarse facial features, inguinal or umbilical hernias, corneal clouding and hepatosplenomegaly.
Sturge Weber syndrome
Neurocutaneous syndrome characterized by congenital unilateral cavernous hemangioma along the trigeminal nerve distribution and radiographic evidence of intra-cranial calcifications that resemble a tramline.
McCune-Albright syndrome clinical features
Precocious puberty, cafe au last spots and multiple bone defects (polyostotic fibrous dysplasia). May be associated iwht other endocrine disorders such as hyperthyroidism, prolactin or GH-secreting pituitary adenomas and adrenal hypercortisolism.
McCune Albright syndrome genetic cause
Defect in the G protein cAMP-kinase function in the affected tissue, thereby resulting in autonomous activity of that tissue.
Potter sequence
Urinary tract anomaly (usually posterior urethral valves) causing anuria/oliguria in utero. This leads to oligohydramnios. Low amniotic fluid subsequently causes pulmonary hypoplasia, flat facies, and libmb deformities.
Why are >95% of men with CF infertile?
Congenital bilateral absence of vas deferens. The accumulation of inspissated mucus in the fetal genital tract obstructs the developing vas deferent. If the testes are descended, spermatogenesis should be normal. However, sperm cannot be ejaculated resulting in transparent or no semen production (obstructive azoospermia).
