Absent tyrosinase (AR), defective tyrosine transporters, or lack of migration of neural crest cells. Ocular albinism is XR
Lack of melanin, increased risk of skin cancer. Inheritance actually variable b/c of locus heterogeneity.
No one specific gene. Sorry.
Bilateral cystic disease with enlarged kidneys at birth. Cysts in liver --> congenital hepatic fibrosis --> portal HTN. Maternal oligohydramnios, Potter's facies, low-set ears, parrot beak nose, and lung hypoplasia.
CTFR, CHR7, (Deletion of Phe 508 causes abnormal protein folding and degradation of channel)
Infertility in males (bilateral absence of vas deferens), failure to thrive in infancy, pancreatic insufficiency amd fat-soluble vitamin deficiency, recurrent pulmonary infections with Pseudomonas and S. aureus, chronic bronchitis, bronchiectasis
Defect in orotic acid phosphoribosyltransferase or orotidine 5'-phosphate decarboxylase
Inability to convert orotic acid to UMP (de novo pyrimidine synthesis pathway). Increased orotic acid in urine, megaloblastic anemia that doesn't improve with administration of B12 or folate, failure to thrive. No hyperammonemia. Rx: Uridine administration
Defect in tyrosine kinase gene blocks B-cell differentiation
Recurrent bacterial infections after 6 months due to opsonization defect. Increased in boys, Labs: normal pro-B, decreased maturation, decreased number of B cells, decreased immunoglobulins of all classes.
Deficiency of alpha-galactosidase A, accumulation of ceramide trihexoside
Peripheral neuropathy of hands/feet, angiokeratomas, cardiovascular/renal disease
Decreased glutathione --> increased RBC susceptibility to oxidant stress. Hemolytic anemia triggered by oxidant stress (sulfa drugs, infections, fava beans)
Absence of HGPRT: :: Defective purine salvage, excess uric acid production. Mental retardation, self-mutilation, aggression, hyperuricemia and gout, choreoathetosis
Duchenne's Muscular Dystrophy
DMD, frame-shift mutation
Weakness in pelvic girdle muscles (use of Gower's maneuver) progressing superiorly, Pseudohypertrophy of calf muscles, fibrofatty replacement of calve muscles, cardiac myopathy, onset before age 5. Diagnose with CPK and muscle biopsy. Dystrophin anchors muscle fibers.
Becker's Muscular Dystrophy
Weakness in pelvic girdle muscles (use of Gower's maneuver) progressing superiorly, Pseudohypertrophy of calf muscles, fibrofatty replacement of calve muscles, cardiac myopathy, onset in adolescence or early adulthood. Diagnose with CPK and muscle biopsy. Dystrophin anchors muscle fibers.
Deficiency of Iduronate sulfatase, accumulation of heparan sulfate, dermatan sulfate
2nd most common cause of mental retardation, macroorchidism, long face with large jaw, large everted ears, autism, mitral valve prolapse
Myotonic Dystrophy (AD)
Myotonia (inability to relax muscles; sustained grip), frontal balding, cataracts, testicular atrophy, cardiac involvement, facial weakness. Increased serum CK from wasting of type 1 fibers.
Friedrich's Ataxia (AR)
Impaired mitrochondrial functioning. Staggering gait, frequent falling, nystagmus, dysarthria, pes cavus, hammertoes. Cause of death is hypertrophic cardiomyopathy. Presents in childhood with kyphoscoliosis.
Flat facies, prominent epicanthal folds, simian crease, gap b/w 1st and 2nd toes, duodenal atresia, congenital heart disease, increased risk of ALL and Alzheimer's. 95% due to nondisjunction, 4% due to Robertsonian translocation.
Severe mental retardation, rocker-bottom feet, micrognathia (small jaw), clenched hands, low-set ears, prominent occiput, congenital heart disease. Death occurs within 1 year. Most common trisomy resulting in live birth after Down Syndrome.
Severe mental retardation, rocker-bottom feet, micropthalmia, microencephaly, cleft lip/palate, holoprosencephaly, polydactyly, congenital heart disease. Death within 1 year.
Hepatic overproduction of VLDL, causes pancreatitis.
AR, Inability to synthesize lipoproteins due to defects in apoB-100 and apoB-48. Lipid accumulation within enterocytes on intestinal biopsy. Failure to thrive, steatorrhea, acanthocytosis, ataxia, night-blindness.