genetics Flashcards
(59 cards)
list X linked dominant dz
fragile X, Rett syndrome, hypophosphatemic ricketts, charcot marie tooth syndrome
List X linked recessive dz
glucose-6-phosphate dehydrogenase deficiency, duchenne muscular dystrophy, Lesch-Nyhan syndrome, hemophilia A and B
environmental factors in xeroderma pigmentosum
degree of exposure to UV light
allelic heterogeneity
nonsense vs missense mutation in factor VIII gene and Beta thalassemia- different mutations in same locus produce same phenotype
locus heterogeneity
mutations at different loci produce similar phenotype- ie. albinism
disease with incomplete penetrance
retinoblastoma and BRCA1 mutations- not everybody with mutated genotype will show phenotype
disease with variable expression
hemochromatosis and neurofibromatosis type 1- varying degrees of severity
dz with pleiotropy
marfan syndrome, cystic fibrosis, PKU- one gene contributes to multiple phenotypic effects
dz with locus heterogeneity
osteogenesis imperfecta
prader willi
loss of paternal allele from 15q at an imprinted locus, or inheriting both 15q from mom (25% uniparental disomy). Hyperphagia and obesity, neonatal hypotonia, hypogonadism
Angelman syndrome
loss of maternal allele from 15q at an imprinted locus, or inheriting both 15q from dad (5% uniparental disomy). Seizures, ataxia, happy disposition, inappropriate laughter
What kind of translocation is philadelphia chromosome
reciprocal
Cri Du Chat
microdeletion in p arm of chrom 5
hypophosphatemic rickets inheritance pattern and presentation
X-linked dominant disorder resutling in increased phosphate wasting at proximal tubule and results in rickets like presentation. Not responsive to vit D
Mitochondrial myopathies inheritance and presentation
mitochondrial mutation- ragged red fibers on muscle biopsy, myopathy, lactic acidosis and CNS diseases. Secondary to failure in oxidative phosphorylation
Achondroplasia
Autosomal dominant. Missense mutation in fibroblast growth factor receptor 3 (FGFR3) on chromosome
4 leads to inhibition of cartilage synthesis at
epiphysial growth plate. Dwarfism: long bones are short and thick, cranial and vertebral bones are spared. Autosomal dominant. Missense mutation in fibroblast growth factor receptor 3 (FGFR3) on chromosome
4 leads to inhibition of cartilage synthesis at
epiphysial growth plate. Dwarfism: long bones are short and thick, cranial and vertebral bones are spared. Autosomal dominant. Missense mutation in fibroblast growth factor receptor 3 (FGFR3) on chromosome
4 leads to inhibition of cartilage synthesis at
epiphysial growth plate. Dwarfism: long bones are short and thick, cranial and vertebral bones are spared. Autosomal dominant. Missense mutation in fibroblast growth factor receptor 3 (FGFR3) on chromosome
4 leads to inhibition of cartilage synthesis at
epiphysial growth plate. Dwarfism: long bones are short and thick, cranial and vertebral bones are spared.
Polycystic kidney disease
Autosomal dominant. Mutation of the PKD-1 gene on chromosome 16 (16 letters in PCK). Enlarged kidneys with tubular cysts bilaterally. Renal insufficiency, hematuria, HTN in middle age. Extra renal- liver cysts, berry aneurisms, mitral valve prolapse, colonic diverticulaAutosomal dominant. Mutation of the PKD-1 gene on chromosome 16 (16 letters in PCK). Enlarged kidneys with tubular cysts bilaterally. Renal insufficiency, hematuria, HTN in middle age. Extra renal- liver cysts, berry aneurisms, mitral valve prolapse, colonic diverticulaAutosomal dominant. Mutation of the PKD-1 gene on chromosome 16 (16 letters in PCK). Enlarged kidneys with tubular cysts bilaterally. Renal insufficiency, hematuria, HTN in middle age. Extra renal- liver cysts, berry aneurisms, mitral valve prolapse, colonic diverticula
Cystic fibrosis
AR. Mutation of CFTR chloride channel on chrom 7. Most common mutation is delta508. Abnormal protein folding. Diagnosis: sweat test. Treatment: N-acetylcysteine (cleaves mucus glycoproteins), infections
List the X linked recessive conditions
Be Wise, Fools GOLD Heeds Silly Hope: Bruton agammaglobulinemia, Wiskott-Aldrich syndrome, Fabry disease, G6PD deficiency, Ocular albinism, Lesch-Nyhan, Duchenne MD, Hunter syndrome, Hemophilia A and B, Ornithine transcarbamylase deficiency.
Duchennes muscular dystrophy
X-linked recessive. Frameshift mutation of dystrophin gene- ineffective protein. Onset by 5 yrs. Calf pseudohypertrophy, proximal muscle weakness, Gowers maneuver, dilated cardiac myopathy, pulmonary infections, elevated CPK. Muscle biopsy shows necrosis, degeneration and regeneratio of fibers, fatty infiltration, decreased dystrophiin. Diagnosis by PCR
Becker muscular dystrophy
X lined recessive. Point mutation in dystrophin gene. Less severe than Duchenne.
Familial adenomatous polyposis
Autosomal dominant. Mutation of APC gene on chrom 5 (5 letters in polyp). Thousands of colonic polyps after puberty, adenocarcinoma by age 40. Increased risk for adenocarcinoma of duodenum, ampulla of vater
glycogen storage diseases
Autosomal recessive
Familial hypercholesterolemia
aka type II hyperlipidemia. Autosomal dominant. Mutation of LDL receptor on chrom 19. Elevated serum LDL, tendon xanthomas (lipid laden macrophages in skin), xanthelasmas around eyes, premature atherosclerosis, early MI
