SNP Shot: Genomic Insights

3-methylcrotonyl-CoA carboxylase deficiency (3-MCC deficiency) is a genetic condition where the body struggles to process specific proteins. Individuals with this deficiency lack sufficient amounts of an enzyme needed to break down proteins that contain the amino acid leucine.

Babies with 3-MCC deficiency often seem healthy at birth, but symptoms usually appear during infancy or early childhood. Symptoms vary in severity, from mild to life-threatening, and can include problems with feeding, repeated vomiting and diarrhea, extreme tiredness (lethargy), and poor muscle tone (hypotonia). Without treatment, it can result in developmental delays, seizures, and coma. Early diagnosis and lifelong management with a restricted protein diet and appropriate supplements can often prevent these complications. Some individuals with the genetic mutations responsible for 3-MCC deficiency may never show any symptoms.

The symptoms of 3-MCC deficiency can resemble those of Reye syndrome, a serious illness that affects children recovering from viral infections like chickenpox or influenza. Reye syndrome is often linked to aspirin use during these viral infections.

Inheritance:

3-MCC deficiency follows an autosomal recessive inheritance pattern. This means a person must inherit two copies of the mutated gene, one from each parent, to have the condition. The parents, who each carry one copy of the mutated gene, are usually symptom-free carriers.