The CGD Café

CGD is an inherited disease, which means that one or both parents pass on a defective gene to their child, even though the parents may be perfectly healhty. In the case of CGD, the genetic defect interferes with the child's ability to fight off certain diseases. It is estimated that one in one million babies is born with CGD, although symptoms of the disorder may not appear until after 3 months of age.

Two-thirds of people with CGD inherit the disease as a sex-linked characteristic, that is, as a defect in a recessive gene found on the X chromosome passed on to a child by its mother. A male has one X chromosome, a female has two. If a woman carries the faulty geneon only one of her X chromosome, she may not be affected by the disorder if normal phagocytes are generated by the other X chromosome. Her sons will have a 50 percent chance of inheriting the defective gene. Her daughters might be carriers of the defective gene but won't develop CGD. However, carriers of the CGD gene appear to be prone to mouth ulcers and certain skin rashes.

Sometimes the normal X chromosomes in a female CGD carrier becomes inactivated early in the development of the embryo. This allows some cases of X-linked CGD to occur in females, although it is much rarer than in males.

Faulty genes lodged on chromosomes other than the X chromosome can also cause CGD. The autosomal recessive form of CGD results when an abnormal gene is inherited from each parent. Both males and females are affected equally by this form of CGD. If only one abnormal gene is present, then the person carries the gene but does not develop the disease.