There are different forms of mental impairment. Some are inherited and some are not. The largest form of inherited mental impairment in males, though it also occurs in females less rarely, is Fragile-X Syndrome. It is a genetic disorder whose incidence afflicts males more often than females, but there are conflicting reports with respect to incidence:
The defective Fragile-X gene affects 1 in 1,000 males and half against as many females.
The syndrome occurs in 1 of every 2,000 male births and about 1 in every 4,000 female births.
It is seen once in every 1,250 male live births, and about once in every 2,000 female live births.
The disorder is said to afflict some 90,000 Americans with 3,000 new cases being diagnosed annually (Edelson 1). While females do not develop the disorder to the same degree as males, they do carry and genetically transmit the disorder more than men “One in 250 women and one in 700 men is a carrier” (Cooke 2). However, other research gives different figures for the rate women carry the disease “About 1 in 700 women carry the gene” (Signor 1). However, these women are not negatively affected by the disorder, and few if any of them show any outward symptoms of it. Women in general are much less affected by the disorder when they do have it and generally do not require drugs or treatment of other kinds. Researchers theorized but do not know for sure that women are less afflicted by the disease because they have two X chromosome while men have only one. When they have a Fragile-X chromosome, the other one helps make up for the mutated gene since it functions normally.
The chromosome known as Fragile-X appears to have a top that is broken or weakly aligned to the chromosome. Because of its mutation, it does not produce enough protein for proper mental and physical development. The disorder was relatively obscure before 1980. It is difficult to diagnose because of an array of symp...