3-M Syndrome - Causes

Causes

3-M syndrome is thought to be inherited as an autosomal recessive genetic trait. Human traits, including the classic genetic diseases, are the product of the interaction of two genes, one received from the father and one from the mother. In recessive disorders, the condition does not occur unless an individual inherits the same defective gene for the same trait from each parent. If an individual receives one normal gene and one gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms. (Again, in the case of 3-M syndrome, some carriers may exhibit some mild symptoms associated with the disorder.) The risk of transmitting the disease to the children of a couple, both of whom are carriers for a recessive disorder, is 25 percent. Fifty percent of their children risk being carriers of the disease, but usually will not show symptoms of the disorder. Twenty-five percent of their children may receive both normal genes, one from each parent, and will be genetically normal (for that particular trait). The risk is the same for each pregnancy. Individuals who carry a single copy of the defective gene for 3-M syndrome (heterozygotes) may exhibit some mild physical findings associated with the disorder (e.g., subtle craniofacial abnormalities and/or unusually slender bones).