AR Diseases Flashcards
1
Q
- Majority of mutant alleles where?
- Compound heterozygote?
- Allelic heterogeneity?
A
- With carriers
- 2 different mutant alleles at same loci can affect severity
- Multiple alleles of a single gene
2
Q
- PKU: Def?
- High where? Low where?
- Phenotype?
- 2 types?
- Screening?
- Treatment?
A
- High phenylalanine in blood
- Scotland, Finland
- High PA in blood and urine, microcephaly, epilepsy
- 1.) most common = defective PAH enzyme (PA-Tyrosine)
2. ) Defective PAH cofactor = effects other enzymes as well - Mass spec; but timing is important so mom’s blood is out of baby
- Diet, especially for pregnant women who can hurt even unaffected child; type 2 needs neurotransmitter drug added as well
3
Q
Alpha 1 - antitrypsin (ATD) deficiency: Def?
- Phenotype?
- Ecogenetics involved how?
- Mechanism involved?
- Possible genotypes? Results in?
A
- Deficient in SERPINA1 protease inhibitor
- Emphesyma, liver cancer, cihrossis
- Smoking effects severity
- Serpina1 inhibits eleastase (released by neutrophils) which inhibits elastin (allows elasticity)
- Z/Z = 15% of normal function
- S/S = 60% of normal function
- S/Z = somewhere in between
4
Q
Tay-Sachs (untreatable): Def? Prominent in?
- Phenotype?
- Mechanism?
- 3 types? Gene affected? Protein affected? Substrate? Enzyme Test?
- Which activated by heat?
- Testing options? (3)
A
- Fatal disorder with destruction of CNS; Ashkenazi Jews
- Muscle weakness, seizures, mental retardation, vegetative state
- Lysosomal storage disorder (defective HexA enzyme) where they can’t degrade ganglioside
- 1.) TS = HexA; alpha subunit; gangliosides; Hex A defective; activated by heat
2. ) Sandhoffs: HexB; B subunit; globosides; both defective
3. ) AB variant: GM2AP; activator of A and B affected; x; both normal - DNA testing, carrier enzyme screen, amniotic fluid test
