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Path 5 Genetics
Path
Question | Answer |
---|---|
Are gain of func or loss of func mutants more common | loss of func |
disorder of connective tissue. autosom dom. defect in fibrillin-1. tall w long extremities, 2x jointed, spinal deformities, long head, pectus deformities, cardiovasc (mitral valve prolapse and ascending aorta dilation). | Marfan synd |
defect in synth or struct of fibrillar collagen. stretchy skin (vulnerable to trauma), hypermobile joints. can have rupture of colon and large aa. (vascular), rupture of cornea/retina detach (kyphoscoliosis: m.c.), diaphrag hernia (classic) | Ehlers-Danlos synd |
mutant LDL receptor->elevated cholesterol->premature atherosclerosis. diverts more IDL toward LDL. class 1-5 muts: synth, transport, binding, internalize, recycle. | Familial Hypercholesterolemia |
most common GM2 gangliosidosis->def hexosaminidase A. Ashkenazis. ganglioside accums mostly in retina->cherry red spot in macula. incoordination, flaccidity, blind, dementia. death by 3 y/o | Tay-Sachs |
lysosomal accum of sphingomyelin d/t def sphingomyelinase. Type A=severe infant form w neuro involve, wasting and early death, foamy cytoplasm w "zebra bods". Type B=organomegaly, no CNS involve, survive to adult. Ashkenazis. HEPATOSPLENOMEGALY | Niemann-Pick A+B disease |
mutant NPC1. cells accum cholest and gangliosides. presents as hydrops fetalis/stillbirth, neonatal hepatitis, chronic w neuro damage. More common. | Niemann-Pick C disease |
most common lysosomal store disorder. mut glucocerebrosidase. Glucocerebroside accum in phagocytes. type 1=mostly splenic and skeletal, non-neuronopathic. type 2=neuronopath, infants, hepatosplen still, no glucocerebroside in tissues. | Gaucher disease |
coarse facial feats, cloudy cornea, stiff joints, MR, urinary excrete of dermatan/heparan/keratan/chondroitin sulfates. | Mucopolysaccharidoses - Hurler synd=def Alpha-1-iduronidase. severe, death by 6-10 y/o. - Hunter synd=X-linked, no cornea clouding, milder. |
def G6P->hepatomegaly and hypoglycemia. Hepatic form | von Gierke disease |
def muscle phosphorylase->muscle cramps and low lactate lvls in blood after exercise. Myopathic form | McArdle disease |
def acid maltase->cardiomegaly | Pompe disease |
lack of homogentisic oxidase->black urine, blue-black tendons/cartilage (ears/nose/cheek). brittle, fibrillated IV discs | Alkaptonuria |
chromosome consisting of two long or two short arms only | Isochromosome |
Most common chromosomal disorder and major cause of MR. flat face, epicanthic folds, simian crease, lots neck skin, heart defects(septal defects). increased risk of leukemias and Alzheimer. | Trisomy 21=Down synd. |
prominent occiput, MR, small mouth, low ears, short neck, overlapped fingers, heart defects, horseshoe kidney, rocker-bottom feet | Trisomy 18=Edwards synd |
small head, polydactyly, small eyes, cleft lip/palate, heart defects, rocker-bottom feet | Trisomy 13=Patau synd |
heart defects, palate probs, facial probs, T-cell immunodef (thymic hypoplasia) and hypocalcemia (parathyroid hypoplasia). high risk schizo and bipolar | DiGeorge synd - 22qll.2 deletion |
male hypogonadism when there are 2 or more X chromos and 1 or more Ys. Elongated body/legs, atrophic testes, small penis, lack of deep voice/beard/male pubic hair, gynecomastia. increased type 2 diabetes and mitral valve prolapse. High FSH, Low testost. | Klinefelter synd |
complete or partial monosomy of X chromo, hypogonadism in phenotypic females. most common sex chromo abnorm in females. neck web, short, low post. hairline, broad chest, coarctation of aorta, infertile, AMENORRHEA (most imp cause). | Turner synd |
X-linked mut familial mental retard-1 gene, CGG repeat expansion. MACRO-ORCHIDISM, large mandible, large everted ears, mitral valve prolapse. | Fragile-X synd |
MR, short, hypotonia, hyperphagia, obesity, small hands/feet, hypogonad. del in paternal chromo 15. | Prader-Willi |
MR, ataxia, seizures, inappropriate laughter (happy puppets). del in maternal chromo 15. | Angelman synd |