intro lecture Flashcards
what is a mendelian disorder?
one that is caused by a mutation at a SINGLE locus
why study medical genetics?
although rare they are clinically important as they can be devastating…also can tell us about common diseases e.g cancer
why ID these genes?
diagnosis leads to treatment + therapy… understand bio of diseases e.g symptoms… early screening… carrier and pre natal screening
proband?
propositus?
propsita?
individual affected (by gen disease)
male
female
pedigree terms:
- consanguineous?
- ) pregnancy?
- ) affected spotted?
- )generations
- ) birth order?
- blood related parents
- ) p inside shape
- ) p (proband) arrow to shape
- ) roman numerals
- ) normal numbers within generation. start at the left
what is meant by dominance and recessive? and give an example
dominance and recessive are properties of characters (and not genes). an example is SCA which is a recessive condition. it is only seen in homozygotes not hetero
semi dominant?
hetero has an intermediate phenotype
what are the mendelian patterns of inheritance?
- autosomal dominance
- autosomal recessive
- x linked dominant
- x linked recessive
- y linked
autosomal dominance?
manifests in hetero
affects males and f equally
from 1 gen to the next
- hetero parent gives offspring 1/2 chance of having condition
autosomal recessive?
heteros healthy
homos affected
consanguineous
horizontal trans (spread through sibship)
offspring has 1/4 chance if both parents hetero
x linked dominant?
determined by gene on x chromosome
males and females affected (f more so)
i.e. xm
x linked recessive?
traits shown in males only because females have one normal x chrom. where as males who are affected have one affected x and a y.
diagonal transmission
what are the unusual patterns of inheritance?
anticipation mosaicism uniparental disomy genomic imprinting mitochondrial inheritance
