The patient journey to diagnosis and treatment of congenital sucrase-isomaltase deficiency

Purpose

Congenital sucrase-isomaltase deficiency (CSID) is a rare genetic disorder characterized by a deficiency of the sucrase-isomaltase (SI) enzyme complex within the brush border membrane of the small intestine. Mutations in the SI gene result in abnormal synthesis and/or incorrect transport of the SI enzyme. Patients with CSID generally have reduced sucrase activity, but levels of isomaltase activity range from absent to almost normal. This study sought to better understand the experience of patients with CSID prior to, during, and after their diagnosis and its subsequent treatment with sacrosidase.

Methods

This was a cross-sectional interview study conducted in conjunction with a longitudinal, observational study of US patients prescribed and taking sacrosidase for at least three consecutive months as treatment for CSID. The observational study included both children and adults.

Results

This qualitative interview study explored the experiences of 43 adult and pediatric patients (n = 8 adults and n = 35 children/adolescents) with CSID pre-, during, and post-diagnosis. Findings suggest that a CSID diagnosis is particularly problematic given the disparate range of more commonly understood gastrointestinal (GI) disorders. After diagnosis and treatment with sacrosidase, participants reported considerable improvement in symptoms and health-related quality of life (HRQL), yet symptoms persist that continue to affect daily life, indicating areas of potential unmet need.

Conclusion

Educating clinicians about CSID may help improve the overall diagnosis experience. As this research is the first of its kind in CSID, additional research, qualitative and quantitative, will be important to furthering the understanding of HRQL impact and unmet need experienced by this population and identifying ways to best meet those needs.

The clinical consequences of sucrase-isomaltase deficiency

Primary sucrase-isomaltase deficiency, originally thought to be a homozygous recessive disorder, has been found to have numerous genetic variants that alone or in combination (compound heterozygosity) express varying degrees of clinical illness, most commonly causing chronic diarrhea, abdominal pain, and bloating. These symptoms are also present with secondary sucrase-isomaltase deficiency. Recent investigations are providing evidence that sucrase-isomaltase deficiency is more prevalent and of greater clinical significance than previously suspected. Further research is required to correlate the specific genotypes and phenotypes with their clinical expressions and to determine the most appropriate treatment algorithm for these patients.