Closeup shot of a new born baby being kept for a CAH screening.

CONGENITAL ADRENAL HYPERPLASIA (CAH)

Congenital adrenal hyperplasia (CAH) refers to a group of genetic conditions that affect the adrenal glands. These glands sit on top of the kidneys and are responsible for releasing various types of hormones that the body needs to function. Affected people lack an enzyme the adrenal glands need to make one or more of these hormones and often overproduce androgens (male hormones such as testosterone).

Males typically appear unaffected at birth even when they have a severe form of CAH and without proper diagnosis, will develop associated health problems within 2-3 weeks after birth.

SYMPTOMS OF CONGENITAL ADRENAL HYPERPLASIA (CAH)

The signs and symptoms present in each person depend on many factors including the type of CAH, the age of diagnosis, and the sex of the affected person. For example, females with a severe form of the condition may have ambiguous genitalia at birth and if not properly diagnosed, develop dehydration, poor feeding, diarrhea, vomiting and other health problems soon after. Males typically appear unaffected at birth even when they have a severe form of CAH and without proper diagnosis, will develop associated health problems within 2-3 weeks after birth.

There are two main types of CAH:

Classic CAH, the more severe form, and
A milder form called Nonclassic CAH.

The Nonclassical form of CAH is not life threatening but can affect: (1) puberty and growth in children, and (2) cause infertility in males and females as well as other symptoms affecting quality of life.In these cases, a diagnosis may not be made until adolescence or adulthood when the affected person experiences early signs of puberty or fertility problems. Females with this type may have excessive facial or body hair; irregular menstrual periods; and/or acne.

Closeup shot of a new born baby crying on the crib.

INHERITANCE OF CONGENITAL ADRENAL HYPERPLASIA (CAH)

CAH is an autosomal recessive genetic disorder. This means that to be affected, a person must have a mutation in both copies of the responsible gene in each cell.

The parents of an affected person usually each carry one mutated copy of the gene and are referred to as carriers.

Carriers typically do not show signs or symptoms of the condition.

When two carriers of an autosomal recessive condition have children, each child has a 25% (1 in 4) risk to have the condition, a 50% (1 in 2) risk to be a carrier like each of the parents, and a 25% chance to not have the condition and not be a carrier.

It affects males and females in equal numbers.

For a child to be born with either form of CAH, both parents must carry a gene for the disorder.

Scientists have pinpointed the location of the group of genes that causes the most common forms of CAH to chromosome 6. Parents of children diagnosed with CAH are advised to seek genetic counselling and DNA testing to detect if they are carriers of the gene mutations.