2. Genetic Disorder
Caused by a mutation of a gene, group of genes
or an entire chromosome.
The mutation or defect is inherited.
Classification:
1. Single gene defect (mendelian disorder)
1. Autosomal (dominant/ recessive)
2. Sex linked (dominant/ recessive)
2. Multifactorial
3. Cytogenic or chromosomal
3. Chromosome-
Carrier of DNA with hereditary information.
Normal somatic cell contains 46 chromosomes
2x 23 pairs
22 pairs autosomes and 1 pair sex chromosomes.
Male – XY
Female – XX
Gene-
Unit of inheritance of character.
Mutation-
Permanent change in the DNA
4. Mendelian disorder
Unifactorial inheritance
Defect in a single gene of large visible effect.
Dominant -
o Manifested even on a heterozygote
Recessive –
o Manifested only if homozygous.
Autosomal –
o Affects both male and females equally
Sex linked / X linked –
o May affect either depending on the gene linked.
o Almost always X-linked and affects male.