Concepts Flashcards
Individual with Recessive disorder with only One parent that is a carrier? Heterozygous indicates error occurred? Homozygous?
Uniparental disomy= Receive 2 copies of a chromosome form 1 parent
Hetero= Meiosis 1
Homo= Meiosis 2
Hardy Weinberg equation?
p2 + 2pq + q2 = 1
p + q = 1
mutation that leads to a nonfunctional altered protein prevents the normal gene form functioning?
Dominant negative mutation
Mutations at different loci can produce same phenotype? examples?
Locus heterogeneity
Marfan + Homocystinuria + MEN 2B == Marfanoid habitus
Presence of both normal and mutated mtDNA resulting in variable expression in inherited disease?
Heteroplasmy
One gene contributes to multiple phenotypic changes?
Pleiotropy
PKU = retardation, hair/skin changes
Pt with large head and short limbs, normal trunk has what mutation associated with Advanced Paternal Age?
Achondroplasia= FGF receptor 3 mutation
AD disease in pt with Achilles xanthomas + MI b4 20yo. Mutation?
Familial hypercholesterolemia= LDL receptor def
AD dz of blood vessels with telangiectasia, recurrent epistaxis, skin discolorations, AVMs?
Osler-Weber Rendu syndrome (hereditary hemorrhagic telangiectasia)
Defect in fibrillin gene is associated with what findings?
Marfans= Tall/long, Cystic medial necrosis, MVP, UPWARD Subluxation of lenses, scoliosis/kyphosis
MEN 2A/2B are associated with what gene?
ret gene mutation
NF1 findings?
Chromosome 17
Lisch nodules (IRIS hamartomas)
Optic Gliomas
Scoliosis
NF 2 findings?
Ch 22
BL acoustic shwannomas
Juvenil CATARACTS
Tuberous sclerosis findings?
Adenoma sebaceum (facial lesions) Hypopigmented lesions (Ash leaf spots) Retinal Hamartomas SEIZURES Mental retardation Renal Angiomyolipomas Cardiac Rhabdomyomas
VHL disease findings?
ch 3 + HIF transcription factor consecutively ON
Bilateral Renal cell carcinomas
Hemangioblastomas (retina/medulla/cerebellum)
What is the underlying defect in CF?
phe deletion @ 508
Abnormal folding of CFTR leading to degradation in the GOLGI rather than implant into membrane
Common Rx of CF?
N-acetylcystine= cleaves Disulfide bonds to loosen mucus
*Rx: acetaminophen OD + Cyclophosphamide hematuria
What are some important X-linked diseases?
DMD Wiskott-adlrich G6PD def BTK def Lesch-Nyhan Hemophilia
Findings of DMD?
X-linked Frameshift mutation Weakness of pelvic muscles Pseudohypertrophy= fibrofatty replacement Cardiac myopathy Increased CPK
Pt with macro-orchadism, long face, large jaw, everted ears, mental retardation, autism, MVP has what mutation?
Fragile X= FMR1 CGG repeats.
Trinucleotide repeat syndromes: CAG= CGG= GAA= CTG=
CAG= Huntingtons CGG= Fragile X GAA= Friedreichs ataxia CTG= myotonic dystrophy
Pt with epicanthal folds, simian crease, ASD, duodenal atresia. what will be the findings on a pregnancy quad screen?
DOWN's syndrome AFP= Decreased Estriol= Decreased B-hCG= Increased Inhibin A= Increased
pt with severe mental retardation, small jaw, clenched hands, heart defects?
Edwards = Trisomy 18 afp= dec B-hCH= dec estriol= dec Inhibin- normal
Pt with mental retardation, small eyes, small head, cleft palate/lip, Polydactyly, heart defect?
Patau’s syndrome= trisomy 13
Robertsonian translocations occurs @ what chromosomes?
Acrocentric = 13, 14, 15, 21, 22
Pt with microcephaly, mental retardation, high pitched cry, VSD has what genetic abnormality?
Cri-du-chat= 5p deletion
Pt with wide spread eyes, short nose, thin upper lip, ADD, VSD/ASD?
Fetal alcohol syndrome
Female with inguinal masses, vagina ending in blind pouch?
Testicular feminization= XR loss of Androgen receptor
