Final answer:
Autosomal chromosomal disorders generally have a greater impact on health than sex chromosomal disorders because autosomes contain more genes critical to development. While sex-linked disorders can have milder effects due to mechanisms like X inactivation, autosomal disorders like Down syndrome can be severely debilitating or even lethal.
Step-by-step explanation:
Chromosomal disorders that involve autosomes tend to have a greater impact on a person’s health compared to those involving sex chromosomes. This is primarily because autosomes carry a larger number of essential genes that are vital for normal development and function. Disorders involving autosomes, such as Down syndrome, can lead to severe physical and mental disabilities. However, because the Y chromosome carries fewer genes, and the X chromosome has a mechanism called X inactivation that can mitigate the effects of extra copies, sex-linked chromosomal disorders often result in milder phenotypic effects.
For instance, Klinefelter syndrome (XXY genotype) is generally less severe than autosomal disorders. In fact, aneuploidies, which are abnormalities in chromosome number such as trisomy 21 that results in Down syndrome, are usually lethal when they occur in autosomes, while similar aberrations in sex chromosomes can still result in viable, albeit often infertile, offspring.
During meiosis, nondisjunction can cause improper segregation of chromosomes leading to gametes with abnormal chromosome numbers. This is a crucial factor in the emergence of both types of chromosomal disorders. Aneuploidies and structural rearrangements such as inversion and translocation can contribute to considerable phenotypic effects, often resulting in reduced fertility or dramatic, often fatal, phenotypes.