Estimating the prevalence of congenital disaccharidase deficiencies using allele frequencies from gnomAD.

BACKGROUND: There are currently three known congenital disaccharidase deficiencies: congenital lactase deficiency (CLD), congenital sucrase-isomaltase deficiency (CSD), and congenital trehalase deficiency (CTD). No congenital deficiency has been described for maltase-glucoamylase (MGAM).

METHODS: A literature search was performed in PubMed for the pathogenic variants CLD, CSD, and CTD and the articles retrieved were analyzed to estimate the prevalence of congenital disaccharidase deficiencies.

RESULTS: Based on reported variants, the estimated prevalence was 1.3 per 106 births (95% CI: 1.1-1.7) for CLD, and 31.4 per 106 births (95% CI: 28.3-34.8) for CSD. Using data on previously reported variants and variants predicted to be loss-of-function in gnomAD, the overall estimated prevalence was 2.3 per 106 births (95% CI: 1.9-2.9) for CLD, 57.6 per 106 births (95% CI:52.5-63.2) for CSD, and 9.2 per 106 births (95% CI: 2.5-3.7) for CTD.

CONCLUSION: The prevalence of CSD was found to be relatively high, while for other congenital disaccharidase deficiencies, the estimated prevalence was very low.