Clinical features and partial proportional molecular genetics in neonatal diabetes mellitus: a retrospective analysis in southwestern China

Purpose: To explore the relationship of phenotype and genotype of neonatal diabetes mellitus (NDM) in southwestern China.

Methods: Sixteen cases of NDM admitted to Children's Hospital of Chongqing Medical University from May 2009 to May 2019 were included in this study. The clinical features of the included infants were retrospectively analyzed. Peripheral blood samples of the patients and their parents were collected for mutation detection.

Results: Among the 16 cases of NDM, 8 cases were permanent neonatal diabetes mellitus (PNDM) (including 3 clinical syndromes), and 3 cases were transient neonatal diabetes mellitus (TNDM). Mutation detection was performed in six cases. The mutation genes and their loci were FOXP3 p.V408M, KCNJ11 p.C166Y, ABCC8 p.S830P, KCNJ11 p.I182T, KCNJ11 p.G334D, and ZFP57 p.R125X,412. ABCC8 p.S830P was the new found pathogenic site of gene mutation. According to the clinical features and follow-up results, one case was diagnosed as IPEX syndrome, two as DEND syndrome, two as simple PNDM, and one as TNDM. All the TNDM could spontaneously alleviate and then insulin was withdrawn. In PNDM, 75% of those with KATP channel gene mutation could be completely or partially converted to oral sulfonylureas treatment, however, the rest cases needed lifelong insulin replacement therapy.

Conclusion: The clinical manifestations and treatment regimens of patients with NDM vary according to the type of gene mutation. Even the same mutant genotype has differences in phenotype and response to treatment.