Chromosomal disorders: These genetic disorders are caused due to absence or excess or abnormal arrangement of one or more chromosomes. These are noninheritable and pedigree analysis of a family does not help in tracing the pattern of inheritance of such chromosomal disorders. These are two types: abnormalities due to aneuploidy and aberrations either in autosomes or in sex chromosomes.
Autosomal vs Sex chromosomal disordersAutosomal disorders:
1. These arise by gene mutations in autosomal chromosomes.
2. These disorders affect both the sexes, i.e., males and females.
3. The mutated gene may be dominant / recessive.
4. The suffer is homozygous or heterozygous, e.g., Down’s syndrome, Huntington's disease’s chorea, sickle cell anemia, alkaptonuria.
Sex chromosomal disorders:
1. These arise by gene mutation in sex chromosomes (mostly X chromosomes.
2. These disorders affect the males more than the females.
3. The mutated gene is recessive.
4. The sufferer is hemizygous, e.g.,Klinefelter’s syndrome,Turner’s syndrome, super female, haemophilia, muscular dystrophy.