congenital sucrase-isomaltase deficiency

Congenital sucrase-isomaltase deficiency is a disorder of carbohydrate absorption that affects the digestive system. It results from mutations in the SI gene, which disrupt the normal breakdown of sucrose and maltose. This condition typically presents in infancy with symptoms such as chronic diarrhea. It is relatively common among rare conditions, affecting approximately 1 to 5 per 10,000 individuals.

The hallmark clinical feature of congenital sucrase-isomaltase deficiency is persistent diarrhea, observed in all affected individuals. In addition to diarrhea, children may experience symptoms of malabsorption such as bloating or discomfort after consuming foods that contain sucrose and maltose. Not all individuals experience every feature, and the severity of symptoms can vary considerably.

This condition is caused by mutations in the SI gene, which encodes an enzyme essential for digesting sucrose and maltose. It is inherited in an autosomal recessive pattern, meaning that affected individuals inherit one defective copy of the gene from each parent. Because both parents are typically asymptomatic carriers, the risk of the disorder is higher in families where parents share a common ancestor.

Currently, management focuses on supportive care and symptom management since there are no specific foundational or approved treatments available for congenital sucrase-isomaltase deficiency. Treatment is individualized, often involving dietary modifications to reduce intake of sucrose and maltose, along with nutritional support to ensure proper growth and development. Patients are encouraged to discuss their options with a multidisciplinary healthcare team and to consider genetic counseling for further information.

The outlook for individuals with congenital sucrase-isomaltase deficiency varies widely, with many patients achieving a good quality of life through appropriate dietary management and supportive care. Outcomes described in medical literature continue to evolve as standards of care improve, and individual experiences differ based on symptom severity and treatment access. Families often find it helpful to connect with genetic counselors and specialists to discuss care strategies and future planning.

Several clinical trials are currently investigating new treatment approaches for congenital sucrase-isomaltase deficiency. Individuals interested in clinical trials can search ClinicalTrials.gov or consult their care team about eligibility.