Clinical and Molecular Disease Spectrum and Outcomes in Patients with Infantile-Onset Pompe Disease

Objectives: To evaluate the clinical and molecular spectrum, and factors affecting clinical outcome of patients in India diagnosed with infantile-onset Pompe disease (IOPD).

Study design: In this multicenter, cross-sectional study, we evaluated the records of 77 patients with IOPD to analyze their clinical course, outcomes, and factors influencing the outcomes.

Results: Of the 77 patients with IOPD, phenotype data were available in 59; 46 (78%) had the classic phenotype. Overall, 58 of 77 (75%) and 19 of 77 (25%) patients were symptomatic before and after age 6 months, respectively. Alpha-glucosidase gene variant analysis available for 48 patients (96 alleles) showed missense variants in 49 alleles. Cross-reactive immunologic material (CRIM) status could be determined or predicted in 44 of 48 patients. In total, 32 of 44 patients (72%) were CRIM-positive, and 12 of 44 patients (27%) were CRIM-negative. Thirty-nine cases received enzyme-replacement therapy (ERT), alglucosidase alfa, and 38 patients never received ERT. Median age at initiation of ERT was 6.5 months. Response to ERT was better in babies who had CRIM-positive, non-classic IOPD.

Conclusions: This study highlights the clinical spectrum of IOPD in India and provides an insight on various factors, such as undernutrition, feeding difficulties, and recurrent respiratory infection, as possible factors influencing clinical outcomes in these patients. The study also reiterates the importance of raising awareness among clinicians about the need for early diagnosis and timely treatment of IOPD.