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Flashcards in Biochem - genetics Deck (9):
1

Cafe au lait spots, polyostotic fibrous dysplasia, precocious puberty

McCune Albright

mutation affecting G-protein signaling, example of mosaicism

2

Locus vs allelic heterogeneity

locus - mutations at different loci = similar phenotype (eg. albinism)

allelic - different mutations in same locus = same phenotype (eg. B-thalassemia)

3

Hyperphagia, obesity, intellectual disability, hypogonadism, hypotonia

Prader-Willi (paternal gene deleted + maternal imprinting/silenced through methylation)

25% of cases due to maternal uniparental disomy

4

Inappropriate laughter, seizures, ataxia, severe intellectual disability

Angelman (paternal imprinting + maternal gene mutated)

5

Most common mutation of CFTR

F508 (phenylalanine)

Causes misfolded protein, which is then retained in RER and not transported to cell membrane, causes decr. Cl secretion

6

Reproduction in CF

males - absent vas deferens
females - amenorrhea, abnormally thick cervical mucus

7

Muscular dystrophy genetic mutations

Duchenne: frameshift --> truncated dystrophin protein

Becker: non-frameshift mutation --> partially function dystrophin protein

Dystrophin = anchor muscle fibers, connects actin cytoskeleton to transmembrane proteins which connect to ECM (loss results in myonecrosis)

8

Four Trinucleotide repeat expansion diseases

Fragile X syndrome (CGG)
Friedrich ataxia (GAA)
Huntington disease (CAG)
Myotonic dystrophy (CTG)

Show genetic anticipation (incr. severity, decr. age of onset)

9

Autosomal trisomies

Down: 21 (Drinking age)

Edwards: 18 (Election age), low-set ears! death w/in 1 yr

Patau: 13 (Puberty) cleft lip, polydactyly, holoprosencephaly, death w/in 1 yr