Genetic Disorders 2

gsafsaf's version from 2015-05-26 22:17


Question Answer
Single Palmar CreaseTrisomy 21
Duodenal atresiaTrisomy 21
Endocardial cushion defectsTrisomy 21
ASDTrisomy 21
VSDTrisomy 21
ALL + AMLTrisomy 21
PolycythemiaTrisomy 21
MosaicismTrisomy 21
Robertsonian TranslocationTrisomy 21
Robertsonian Translocation5% of Down's; Very long arm from 2 fused chromosomes (45 chromosomes) predisposes offspring to Down's who have 46 chromosomes but an extra arm of chromosome 21 is attached to another chromosome
Rocker bottom feet Trisomy 13
Rocker bottom feet Trisomy 18
MicrognathiaTrisomy 18
Cleft lip/palateTrisomy 13
HoloprosencephalyTrisomy 13
PolydactylyTrisomy 13
Nondisjunction of homologous chromosomes Trisomy 21 (95%)
Clenched handsTrisomy 18
Edwards SyndromeTrisomy 18
Patau SyndromeTrisomy 13
Abnormal connections btwn heart chambers Trisomy 21
Prominent OcciputTrisomy 18
Death often 1 year after birthTrisomy 18
Death often 1 year after birthTrisomy 13

Quad Test

Question Answer
Low AFPTrisomy 21
Low EstriolTrisomy 21
High hCGTrisomy 21
High Inhibin ATrisomy 21
Low AFPTrisomy 18
Low EstriolTrisomy 18
Low hCGTrisomy 18
Normal Inhibin ATrisomy 18
Low hCGTrisomy 13
Low PAPP-ATrisomy 13
Increased nuchal translucency on ultrasoundTrisomy 21
Increased nuchal translucency on ultrasoundTrisomy 13
Increased nuchal translucency on ultrasoundTurner Syndrome

Sex Chromosome Disorders

Question Answer
47, XXYKlinefelter syndrome
45, XOTurner Syndrome
Testicular atrophyKlinefelter syndrome
Tall + long extremities Klinefelter syndrome
GynecomasyiaKlinefelter syndrome
Presence of inactivated X chromosome (Barr Body)Klinefelter syndrome
Dysgenesis of seminiferous tubulesKlinefelter syndrome
Common cause of hypogonadism seen in infertility workupKlinefelter syndrome
Short Turner Syndrome
Ovarian dysgenesisTurner Syndrome
Webbed neckTurner Syndrome
Shielded chestTurner Syndrome
MC cause of primary amenorrheaTurner Syndrome
Streak OvariesTurner Syndrome
Bicuspid aortic valveTurner Syndrome
Coarctation of aortaTurner Syndrome
MosicisimTurner Syndrome
Decreased EstrogenTurner Syndrome
Increased LH + FSHTurner Syndrome
Decreased inhibinKlinefelter syndrome
Increased FSHKlinefelter syndrome
47, XYYDouble Y Male
Phenotypically normalDouble Y Male
TallDouble Y Male
Severe acneDouble Y Male
Can result from mitotic or meiotic errorTurner Syndrome
Horseshoe kidneyTurner Syndrome
Increased LH + FSHKlinefelter Syndrome
Random nondisjunction eventDouble Y Male
Microdeletion of the long arm of chromosome 7Williams Syndrome
Microdeletion at chromosome 22q11 + thymic, parathyroid, and cardiac defects95% of DiGeorge Syndrome
Microdeletion at chromosome 22q11 + palate, facial, and cardiac effectsVelocardiofacial syndrome

Autosomal dominant

Question Answer
FGF3 Receptor mutationAchondroplasia
Paternal advanced ageAchondroplasia
PDK1 gene on chromosome 16ADPKD (85%)
PDK2 gene on chromosome 4ADPKD
APC geneFamilial adenomatous polyposis
APC geneGardner's Syndrome
Osteomas, lipomas, colon polypsGardner's Syndrome
Chromosome 5qFamilial adenomatous polyposis
Presents after pubertyFamilial adenomatous polyposis
Type IIA hyperlipidemiaFamilial hypercholesterolemia
Absent or defective LDL receptorFamilial hypercholesterolemia
Early MI (as early as 20yo)Familial hypercholesterolemia
aka Osler-Weber-Rendu syndromeHereditary hemorrhagic telangiectasia
Skin discolorationsHereditary hemorrhagic telangiectasia
EpistaxisHereditary hemorrhagic telangiectasia
Increased MCHCHereditary spherocytosis
Spectrin or ankyrin defectHereditary spherocytosis
Increased blood viscosityHereditary spherocytosis
Treatment = splenectomyHereditary spherocytosis
Decrease GABAHuntington's disease
Decrease ACh in brainHuntington's disease
Chromosome 4Huntington's disease
Caudate atrophyHuntington's disease
FBN1 geneMarfan's syndrome
Chromosome 15Marfan's syndrome
Defective fibrillinMarfan's syndrome
MEN1Pituitary adenomas
MEN1Pancreatic tumors
MEN1Parathyroid Adenomas
MEN2AParathyroid Adenomas
MEN2AMedullary thyroid carcinoma
MEN2BMedullary thyroid carcinoma
MEN2BMucosal neuromas/Marfanoid habitus
MEN2Agermline mutation of RET proto-oncogene; allows multiple endocrine organs to be affected bc they have the same origin - neural crest cells
MEN2Bgermline mutation of RET proto-oncogene; allows multiple endocrine organs to be affected bc they have the same origin - neural crest cells
Chromosome 17Neurofibromatosis type 1
Chromosome 22Neurofibromatosis type 2
Bilateral acoustic schwannomasNeurofibromatosis type 2
CataractsNeurofibromatosis type 2
Pigmented iris hamartomasNeurofibromatosis type 1
100% PenetranceNeurofibromatosis type 1
Incomplete PenetranceTuberous sclerosis
Deletion of VHL gene on chromosome 3von Hippel-Lindau disease
Capillary-rich hemangioblastomasvon Hippel-Lindau disease
Mutation --> over expression of HIF-1 --> increased VEGF + EPOvon Hippel-Lindau disease
Peutz-Jeghers syndromeMultiple benign hamartomatous GI polyps - can cause bowel obstruction
Peutz-Jeghers syndromeincreased malignancy risk in GI tract, also breast/ovarian/uterine cancer risk
Peutz-Jeghers syndromeHyperpigmented areas in the lips, mouth, hands, genitalia
HNPCC (Lynch syndrome)Nonpolyposis colorectal cancer due to mutation in DNA mismatch repair system

Autosomal Recessive

Question Answer
Decreased ability to repair DNA after UV light damageXeroma Pigmentosum
Defects in DNA excisional repairXeroma Pigmentosum
Hypersensitivity to DNA cross-linking agentsFanconi anemia
Slight elevation of indirect bilirubin due to reduced activity of glucuronyltransferaseGilbert syndrome
Benign + asymptomatic; slight jaundice under stressGilbert syndrome
Elevation in indirect bilirubin; do to reduced or complete absence of UDP glucuronosyltransferaseCrigler-Najjar syndrome
Can lead to kernicterus in infants, Rx w plasmapheresis + phototherapyCrigler-Najjar syndrome Type I
Rx w phenobarbital is effectiveCrigler-Najjar syndrome Type II
Increase in conjugated bilirubin-trouble putting it into bile, so it remains in hepatocytes; black liver, benign, no Rx neededDubin-Johnson syndrome
Impaired excretion of copper into bile + impaired conversion of copper to ceruloplasminWilson disease
Defect in enzyme ATP7BWilson disease
Hemolytic anemia; hepatoencephalopathy --> dementia; basal ganglia degeneration --> Parkinsonian SxWilson disease
Fanconi syndromeWilson disease

Lysosomal Storage Diseases

Question Answer
Fabry diseaseX-linked recessive
Fabry diseasealpha-galactosidase deficiency
Fabry diseaseceramide trihexoside accumulation
Fabry diseaseangiokeratomas, cardiac + renal involvement, painful neuropathy
Gaucher diseaseAutosomal recessive
Gaucher diseaseß-glucocerebrosidase deficiency
Gaucher diseaseGlucocerebroside accumulation
Gaucher diseasemacrophages that look like crumpled tissue paper, hepatosplenomegaly, pancytopenia, severe bone + join pain
Hurler syndromeAutosomal recessive
Hurler syndromealpha-L-iduronidase deficiency
Hurler syndromeDermatan and heparan sulfate accumulation
Hurler syndromeGargoylism, corneal clouding, hepatosplenomegaly, developmental delay
Hunter syndromeX-linked recessive
Hunter syndromeDermatan and heparan sulfate accumulation
Hunter syndromeHepatosplenomegaly, developmental delay
Niemann-Pick diseaseAutosomal recessive
Niemann-Pick diseaseSphingomyelinase deficiency
Niemann-Pick diseaseSphingomyelin accumulation
Niemann-Pick diseaseHepatosplenomegaly, cherry-red spot in macula, foam cells, neurodegeneration
Tay Sachs diseaseAutosomal recessive
Tay Sachs diseaseß-hexosaminidase A
Tay Sachs diseaseGM2 gangloside accumulation
Tay Sachs diseaseCherry-red spot in macula, progressive neurodegeneration, no hepatosplenomegaly
Krabbe diseaseAutosomal recessive
Krabbe diseaseGalacto-cerbroside deficiency
Krabbe diseaseGalactosyl-sphingosine + galactocerbroside accumulation
Krabbe diseaseProgressive neurodegeneration, optic atrophy
Metachromatic leukodystrophyAutosomal recessive
Metachromatic leukodystrophyArylsulfatase A deficiency
Metachromatic leukodystrophyCerebroside sulfate accumulation
Metachromatic leukodystrophyDestruction of myelin, Muscle wasting, dementia, ataxia

X-linked recessive

Question Answer
Lesch-Nyhan syndromeDeficiency of hypoxanthine-guanine phosphoribosyltransferase (HGPRT)
Lesch-Nyhan syndromeFailure of purine salvage pathway --> increased degradation of guanine and hypoxanthine bases into uric acid --> hyperuricemia
Lesch-Nyhan syndromeExcessive levels of phosphoribosyl-pyrophosphate (PRPP), bc it is not being used by a deficient enzyme + leads to increased activity of enzymes involved in de novo purine biosynthesis

Trinucleotide repeat expansion diseases

Question Answer
Fragile X Syndrome(CGG)n
Fragile X SyndromeMacroorchidism, long face w large jaw, large everted ears
Fragile X SyndromeMVP
Fragile X Syndrome>200 trinucleotide repeats on FMR1 gene causes hypermethylation of cytosine bases --> gene inactivation
Fragile X Syndrome2nd mc cause of intellectual disability, mc cause of inherited intellectual disability