SNP Shot: Genomic Insights

Galactosemia is a metabolic disorder that disrupts the body's ability to process galactose, a simple sugar found in various foods. It's a component of lactose, a larger sugar present in dairy products and many infant formulas. The symptoms of galactosemia stem from the body's inability to utilize galactose for energy production.

Several types of galactosemia have been identified, each caused by mutations in specific genes that affect different enzymes crucial for galactose breakdown.

Classic galactosemia, also known as type I, represents the most prevalent and severe form of the disorder. Without prompt treatment involving a low-galactose diet, infants with classic galactosemia can experience life-threatening complications within days of birth. Common symptoms include feeding problems, lethargy, failure to thrive, jaundice, liver damage, and abnormal bleeding. Sepsis and shock are other potential serious complications. Furthermore, affected children face an increased risk of developmental delays, cataracts, speech impairments, and intellectual disability. Females may also experience premature ovarian insufficiency, leading to reproductive issues.

Galactosemia type II (galactokinase deficiency) and type III (galactose epimerase deficiency) present with different symptom profiles. Type II galactosemia generally leads to fewer medical problems compared to the classic form, primarily causing cataracts with limited long-term complications. Type III galactosemia exhibits a range of symptom severity, from mild to severe, and may include cataracts, delayed growth and development, intellectual disability, liver disease, and kidney problems.

Inheritance:

Galactosemia follows an autosomal recessive inheritance pattern. This means that an affected individual must inherit two copies of the mutated gene, one from each parent. The parents, who each carry a single copy of the mutated gene, are typically asymptomatic carriers.