MCP Flashcards
mutation
permanent, heritable change in the sequence of genomic DNA
Inherited gene complement
mutations which are transmitted from one or both parents
Acquired gene complement
subset of cells in an individual that arose by clonal propagation from a single mutation in one cell
syndrome
characteristics which occur together and are assumed to have a common basis; variable presentation; ex: VCF syndrom
Inborn errors of metabolism
genetically determined biochemical disorders in which a specific enzyme defect produces a metabolic block; all autosomal; usually recessive.
Alcaptonuria
build-up of homogenistic acid in blood; black deposits
albinism
mutation of tyrosine oxidase; no pigments made – can be complete or partial; complete are extremely sensitive to UV light
salvage pathways
to avoid the over accumulation of a potentially toxic substance in cells
Phenylalanine hydroxylase deficiency
a treatable inherited disease in which the body cannot properly process the amino acid phenylalanine
Classiacal PKU
Autosomal recessive, 1/10,000; most common/severe; absence or near absence of phenylalanine hydroxylase. High levels of PHE are converted to a toxic phenylpyruvic acid.
Variant PKU
intermediate form
Tetrahydrobiopterin (BH4) deficiencies
BH4 helps process PHE, but is also important in the brain for NT synthesis. Worsens over time; Rx w/ L-Dopa or OH-Trp.
X-linked Lysosomal storage disease(s)
Hunter and Fabry diseases
Tay-Sachs
hexosaminidase A deficiency; rare autosomal recessive (common among Ashkenazi Jews); 6mo onset; dead by 4. clinical gem: cherry red spot
mucopolysaccharidoses
Hurler, Hunter (x-linked) and Hurler-Scheie; . Rx ~bone marrow transplant, enzyme replacement therapy, gene therapy.
Osteogenesis imperfecta
mutation in type 1 collagen; type II: perinatal lethal.
Class IV: mild to moderate bone deformity/fracturing,
Class III: intermediate.
Ehler-Danlos Syndrome
post-translational modification of collagen (like COL5A/COL3A)
Marfan syndrome
mutations I the fibrilin gene; tall, thin, long fingers. dislocated lens, joint laxity and dissection of the aorta
Recombination/Crossover
exchange btwn homologous chromosomes; Meiosis I
Reduction Division
Meiosis I; centromeres/ chromatids remain attached - homologs separate.
reduces the total number of chromosomes from 2N to N
At the end of reduction division you have__________?
two haploid daughter cells (each chromosome has two chromatids).
Heterodisomy
a cell w/ 2 different copies of a chromosome (both parents: A1/A2 instead of one or the other).
(Nondisjunction at anaphase I)
Isodisomy
a cell with two chromosomes from same source (A1/A1) nondisjunction at Meiosis II
Lyon Hypothesis
for determination of females, there must be two active Xs; inactivation occurs 3-7days after fertilization.