Congenital alactasia

Congenital Alactasia is a rare genetic disorder characterized by the complete absence of lactase enzyme in infants from birth. Lactase is crucial for the digestion of lactose, the main sugar found in milk and dairy products. This condition leads to lactose intolerance from birth, with affected individuals unable to process lactose effectively, resulting in symptoms such as diarrhea, bloating, and abdominal pain when consuming milk-based products.

Causes

Congenital alactasia is caused by mutations in the LCT gene, which provides instructions for making the lactase enzyme. This condition is inherited in an autosomal recessive pattern, meaning both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Symptoms

The primary symptoms of congenital alactasia manifest as a reaction to the ingestion of lactose and may include:

• Diarrhea
• Bloating
• Abdominal cramps
• Gas
• Nausea

These symptoms can vary in severity and often appear within a few hours after consuming milk or dairy products.

Diagnosis

Diagnosis of congenital alactasia involves a combination of medical history assessment, physical examination, and diagnostic tests. Tests may include:

• Hydrogen breath test, which measures the amount of hydrogen in the breath after consuming a lactose-loaded drink. Elevated levels of hydrogen indicate improper digestion of lactose.
• Stool acidity test, useful for infants and young children, measures the acidity in the stool that results from undigested lactose creating lactic acid and other fatty acids.
• Genetic testing can confirm the presence of mutations in the LCT gene.

Treatment

There is no cure for congenital alactasia, and treatment focuses on managing symptoms through dietary modifications. This includes:

• Eliminating lactose-containing foods from the diet
• Using lactose-free milk and dairy products
• Supplementing calcium and vitamin D to prevent deficiencies

Prognosis

With appropriate dietary management, individuals with congenital alactasia can lead healthy lives without experiencing the discomfort associated with lactose ingestion. It is important for patients and caregivers to be educated about the condition and to carefully manage the diet to avoid symptoms.

See Also

• Lactose intolerance
• Lactase
• Genetic disorders
• Autosomal recessive inheritance