A Case of Transient Neonatal Diabetes Mellitus Attributable to a Nonspecific Mutation in the ABCC8 Gene

Neonatal diabetes mellitus (NDM) is defined as hyperglycemia that persists for more than 2 weeks and requires insulin therapy. NDM principally occurs before 6 months of age. Transient NDM (TNDM) is a clinical form of NDM that persists for a median of 12 weeks and resolves completely by 18 months. However, it may relapse as type 2 DM during early adulthood. The major causes of TNDM are mutations in chromosome 6q24 or the KCNJ11 or ABCC8 genes; the latter encode the two subunits of the pancreatic adenosine triphosphate (ATP)-sensitive potassium channel (KATP-channel). This condition responds well to oral sulfonylurea therapy. Herein, we report a neonate who was small for gestational age and exhibited TNDM symptoms. Genetic analysis revealed a nonspecific mutation in ABCC8; he was successfully treated with oral sulfonylurea.

Severe Dental Disease as a Presenting Sign of Relapsed 6q24-Related Transient Neonatal Diabetes Mellitus

Transient neonatal diabetes mellitus (TNDM) is a rare form of diabetes that presents in infancy and is characterized by intrauterine growth restriction and hyperglycemia without ketones on urinalysis. Patients are treated with insulin until remission, usually within the first year. Relapse to a permanent state may occur later in life, with a mean age of 14 years. The most common cause of TNDM is a chromosome 6q24 mutation that affects pancreatic β-cell function. Reports of relapse have been limited. We describe a case of an adolescent female with TNDM due to 6q24 hypomethylation who relapsed at 15 years of age with severe dental disease as the presenting sign.

Duplication 6q24: More Than Just Diabetes

Chromosome 6q24-related transient neonatal diabetes mellitus is characterized by intrauterine growth restriction and low birth weight, with neonatal hyperglycemia resolving by 18 months and an increased risk for type 2 diabetes in adulthood. Molecularly, it is caused by overexpression of the 6q24 imprinted chromosomal region due to a duplication, uniparental disomy, or abnormal methylation. Conventional testing for this condition analyzes methylation patterns at the 6q24 locus but does not evaluate for the presence of other surrounding chromosomal abnormalities. We report a female with a history of neonatal hyperglycemia due to a paternally inherited duplication at chromosomal location 6q24. She subsequently presented to the pediatric genetics clinic at 15 months of age with developmental delay and abnormal balance. Microarray analysis identified a larger 14 Mb chromosomal duplication from 6q24 to 6q25.2, consistent with a diagnosis of duplication 6q syndrome. This case highlights the clinical importance of pursuing further genetic evaluation in patients diagnosed with chromosome 6q24-related neonatal hyperglycemia via targeted methylation-specific multiplex ligation-dependent probe amplification analysis identifying a duplication in this region. Early identification and intervention can improve developmental outcomes for patients with larger chromosome 6q duplications.

A Triplication of 6q24 and Meconium Pseudocyst: A Case Report

With the rise in genetic screening both pre- and postnatally, new variances in genes are being recognized. Some are of unknown significance, while other known genetic expressions have obvious phenotypical expressions. Transient neonatal diabetes mellitus is a result of the duplication of chromosome 6q24, but little is known about the phenotypic expression of a triplication of chromosome 6q24. This case study presents an infant with a postnatally diagnosed triplication of chromosome 6q24, meconium pseudocyst, and multiple congenital anomalies with unknown genetic significance.

Successful transition to sulfonylurea therapy in two Iraqi siblings with neonatal diabetes mellitus and iDEND syndrome due to ABCC8 mutation

Neonatal diabetes is a rare form of monogenic diabetes characterised by persistent hyperglycaemia during the first 6–9 months of age. About half of the cases of neonatal diabetes are transient forms resulting from mutations in the genes in the imprinted region of chromosome 6q24 and the other half are permanent forms. Activating mutations in the potassium ATP (K