Congenital Adrenal Hyperplasia (CAH)

Congenital adrenal hyperplasia (CAH) represents a group of rare inherited disorders affecting the adrenal glands located above the kidneys. It can affect both girls and boys. 

The adrenal glands produce:  

1. Cortisol, which regulates the body’s response to illness or stress;  
2. Aldosterone, which regulate salt and water levels;  
3. Androgen precursors, which are male sex hormones.  

People with CAH cannot make cortisol properly and in some cases are unable to produce aldosterone. They also produce too much of certain androgens. 

CAH is a group of inherited autosomal recessive diseases characterised by a deficiency of one of the enzymes needed to make specific hormones. An autosomal recessive disorder means two copies of an abnormal gene must be present in order for the disease to develop. 

An enzyme deficiency will make the body unable to produce one or more of these hormones, which in turn will result in the overproduction of another type of hormone precursor in order to compensate for the loss. 

The severity of the disease is determined by the severity of the deficiency. 

Before a baby is born, CAH may be diagnosed via prenatal ultrasound. At birth, an atypical appearance of the genitalia may indicate CAH in girls. When babies are born, a heel prick (Guthrie card) is performed to test for metabolic diseases. If this test shows abnormal results, it may indicate CAH. 

Additional examinations are required to confirm the diagnosis or guide treatment: 

• Blood analysis to check levels of adrenal hormones, sodium and potassium  
• Ultrasound to obtain further information about the genital anatomy 
• Genetic testing 
• Stimulation of the adrenal glands 

CAH can cause decreases in blood sugar. Babies and young children are particularly sensitive to this. 

Often CAH also causes excessive salt loss through the urine and other body fluids. This causes dehydration and a drop in blood pressure, which can be life-threatening in severe cases. 

Overproduction of androgens causes unusual physical characteristics: 

• Girls: a large clitoris, fusion of the labia, increased body hair, rapid growth and early puberty 
• Boys: rapid growth, increase in muscle mass, penis enlargement and early puberty 

Once CAH is diagnosed, treatment is started immediately. The treatment consists of the administration of medicine to compensate for the lack of cortisol and aldosterone hormones. 

In the long term, genital surgery can be considered.