An unusual combination of latent autoimmune diabetes in young and maturity-onset diabetes in young.

Type 1 diabetes mellitus (T1DM) is the most common form of diabetes in young people, and the prevalence of type 2 diabetes mellitus (T2DM) is increasing due to obesity. Latent autoimmune diabetes in adults (LADA) typically presents after age 30, and these patients do not require insulin during the first 6 months after diagnosis. A similar clinical profile presenting before age 30 is known as latent autoimmune diabetes in young (LADY). Maturity-onset diabetes in young (MODY) is a monogenic form of diabetes classified into 14 subtypes based on the pathogenic gene variant and systemic manifestations. We present a 22-year-old woman who was incidentally found to have diabetes at age 18 and had a positive glutamic acid decarboxylase (GAD) antibody. She received oral hypoglycemic agents for the first 4 years and recently started insulin due to poor glycemic control. Whole exome sequencing revealed a heterozygous single-base pair deletion in exon 11 of the carboxyl ester lipase (CEL) gene (chr9:g.133071542del; c.2040del; p.Val681CysfsTer23), suggestive of CEL-MODY, also known as MODY 8. Our report highlights the unusual occurrence of double diabetes (LADY and MODY) in a young woman.