DEVELOPMENTAL & GENETIC DISEASE

Teratogens -Factors that cause developmental disease -3 known types Physical Chemical Microbial

Physical Teratogens

Chemical Teratogens

Microbial Teratogens Two types: – Direct: infects mother – Indirect: infects fetus. (TORCH syndrome)

Chromosomal Abnormalities

Structural Abnormalities TypeSymbolNature Translocationt Two chromosomes break, rejoin, and exchange segments DeletiondelA segment of chromosome is lost Inversioninv Two breaks occur; the middle piece is rotated and re-joins Fragile sitefraA chromosomal site with a tendency to break Heterochromic site h Chromosomal region that stains differently from the rest, often of variable size in the normal population DuplicationdupDuplication of a segment of chromosome Ringr Arises from breaks in both arms, with loss of both ends to form a ring

Karyotype Nomenclature 46,XY, t(9;22)(q34;q11) Total number of chromosomes Sex chromosome constitution Description of abnormalities

Deletions

Translocations

Numerical Abnormalities

Numerical Abnormalities of Autosomes

Numerical Abnormalities of Sex Chromosomes

Autosomal Dominant Disorders

Autosomal Recessive Disorders

Sex linked Recessive Disorders

Sex linked Dominant Disorders

Multiple triple repeats disorders

Prenatal Diagnosis