Glutaric acidemia type 2
How is glutaric acidemia type 2 inherited?
Glutaric acidemia type 2 (GA-2) is an autosomal recessive disorder. This means people with GA-2 must have genetic changes on both copies of the gene, in order to have the condition. The genes are located on chromosomes and in every cell of the body there are 46 chromosomes. The chromosomes come in pairs and are comprised of 22 numbered pairs(autosomes) and a pair of gender chromosomes(XX in females and XY in males). Except for the gender chromosomes, each individual has 2 copies of every gene on every chromosome. Both parents of a child with GA-2 are "carriers" for a genetic change associated with the disease. Carriers do not have signs or symptoms of GA-2 themselves because they only have one gene for the condition, but they can pass on their genetic changes to their children. With each pregnancy, each carrier parent has a 50% chance of passing on the gene.
When two GA-2 carriers have a child, there is a 1 in 4 (or 25%) chance to pass on both abnormal genes and have an affected child with GA-2; a 1 in 4 (25%) chance to pass on both normal copies of the gene and not have an affected or carrier child; and a 2 in 4 (50%) chance to have a child that is a carrier of GA-2 like the parent. In other words, there is a 1 in 4 chance in each pregnancy to have an affected child and a 3 in 4 (75%) chance to have an unaffected child. While it is not possible to control which genes are passed on, there is testing that can be done during a pregnancy or after a baby is born to determine if the child will have GA-2 or not.
SOURCE: Emory University - Department of Human Genetics in collaboration with ThinkGenetic • https://www.thinkgenetic.com/diseases/glutaric-acidemia-type-2/inheritance/3305 • DATE UPDATED: 2016-06-26