Etiologic distribution and clinical characteristics of pediatric diabetes in 276 children and adolescents with diabetes at a single academic center

Applications of genomic research in pediatric endocrine diseases

Recent advances in molecular genetics have advanced our understanding of the molecular mechanisms involved in pediatric endocrine disorders and now play a major role in mainstream medical practice. The spectrum of endocrine genetic disorders has 2 extremes: Mendelian and polygenic. Mendelian or monogenic diseases are caused by rare variants of a single gene, each of which exerts a strong effect on disease risk. Polygenic diseases or common traits are caused by the combined effects of multiple genetic variants in conjunction with environmental and lifestyle factors. Testing for a single gene is preferable if the disease is phenotypically and/or geneically homogeneous. Next-generation sequencing (NGS) can be applied to phenotypically and genetically heterogeneous conditions. Genome-wide association studies (GWASs) have examined genetic variants across the entire genome in a large number of individuals who have been matched for population ancestry and assessed for a disease or trait of interest. Common endocrine diseases or traits, such as type 2 diabetes mellitus, obesity, height, and pubertal timing, result from the combined effects of multiple variants in various genes that are frequently found in the general population, each of which contributes a small individual effect. Isolated founder mutations can result from a true founder effect or an extreme reduction in population size. Studies of founder mutations offer powerful advantages for efficiently localizing the genes that underlie Mendelian disorders. The Korean population has settled in the Korean peninsula for thousands of years, and several recurrent mutations have been identified as founder mutations. The application of molecular technology has increased our understanding of endocrine diseases, which have impacted on the practice of pediatric endocrinology related to diagnosis and genetic counseling. This review focuses on the application of genomic research to pediatric endocrine diseases using GWASs and NGS technology for diagnosis and treatment.

Further evidence supporting the role of DUT gene in diabetes with bone marrow failure syndrome

In 2017, a homozygous DUT mutation was reported to cause a syndrome of diabetes and bone marrow failure. However, no further patient with this combination has been reported and the phenotype of heterozygous DUT mutation is unknown. We describe the genotype, phenotype, and post bone marrow transplantation (BMT) data of two unrelated families with this rare syndrome. Whole-exome and/or direct sequencing of the DUT gene were performed in all family members. Each family has two children presented within the first 10 years of life with thrombocytopenia, macrocytosis, with or without anemia, followed by non-autoimmune diabetes. The same homozygous missense DUT mutation, reported in 2017 (c.425A>G p.(Tyr142Cys), was detected in all affected children. The heterozygous carriers have no BM failure, one developed type 2 diabetes, and the rest have normal fasting glucose, insulin, HbA1c, and c-peptide. Multiple nevi were detected in homozygous and heterozygous mutation carriers. Allogenic BMT normalized BM aplasia without impact on diabetes. Post BMT follow-up revealed normal puberty and school performance; but three have height <2.5 SDS. We add two families with this syndrome supporting a role of DUT in bone marrow and β-cell function. The heterozygous carriers of this DUT mutation appear to be healthy.