CHROMOSOMAL DISORDERS
- disorders in structure of chromosome
- Due to break in chromosomes some part of chromosome containing important genes is lost
- DELETION
- types
- microscopic deletions
- deletion of short arm of chromosome 5
- cri-du chat syndrome
- short arm of chromosome 4
- wolf-hirschhborn syndrome
- submicroscopic microdeletions
- syndrome
- prader villi syndrome
- angelmann syndrome
- wilms tumour
- williams
- langer giedion
- miller dieker
- di-george
- INVERSION
- single chromosome breaks at two points
- broken segment rearranges itself
- inverting its position
- pericentric
- paracentric
- RING CHROMOSOMES
- ISOCHROMOSOMES
- TRANSLOCATION
- reciprocal translocation
- exchange between two non-homologous chromosomes
- after breakage and exchange of fragments
- examples
- translocation of chromosome 11 and 22
- robertsonian translocation
- due to break near centromere in two acrocentric chromosomes
- short arm of both chromosomes lost
- but long arms get fused to form a new chromosome
- chromosome number is reduced to 45
- examples
- chromosome 13 and 14
- MOSAICISM / CHIMAERISM
Discussion