Permanent Neonatal Diabetes with High Insulin Requirements due to a New Variant in the INS Gene

Neonatal diabetes is an infrequent disorder that may present as transient, permanent, or syndromic. It is most commonly caused by pathogenic variants involving the ABCC8, KCNJ11, and INS genes. This report describes a neonate with permanent diabetes mellitus due to a previously unreported variant in the INS gene, outlining the diagnostic complexities, therapeutic interventions, and related clinical challenges. The neonate with a history of symmetrical intrauterine growth restriction presented with severe hyperglycemia not associated with ketosis or infectious. He had high insulin requirements and did not respond to sulfonylurea management. Anti-insulin and anti-islet pancreatic antibodies were negative. Genetic sequencing revealed a homozygous missense variant (c.3G>A, p.Met1Ile) in INS, which had not been previously reported. Timely molecular diagnosis of neonatal diabetes enabled optimization of management strategies, mitigating the long-term impact on growth, neurodevelopment, and the occurrence of hypoglycemic episodes.