Endocrine Abstracts

An eight-year-old girl developed Insulin Dependent Diabetes Mellitus. Two years previously, she had been referred to the Department of Endocrinology with concerns regarding short stature, but had not attended. She was mildly dysmorphic and her height and weight both plotted to below the 0.4th centile for age (Height Standard Deviation Score = -3.75, Weight Standard Deviation Score = -2.28). Her mother was also noted to be short at 147.2cm. There was no family history of deafness or diabetes mellitus although her mother had been investigated extensively for chronic fatigue.

At subsequent review her mother stated that her child had been having episodes of eye flickering and therefore an EEG was performed. This showed features consistent with possible juvenile absence or myoclonic epilepsy. In view of this constellation of features, blood was sent for serum lactate (which was normal) and mitochondrial genetic analysis.

MtDNA analysis revealed the A3243G mutation which has been associated with Myopathy, Encephalopathy, Lactic Acidosis and Stroke-like episodes (MELAS) and Maternally Inherited Deafness and Diabetes (MIDD). There was no family history of either of these.

This case highlights that mitochondrial mutations may be responsible for childhood onset Diabetes Mellitus especially when associated with maternally inherited short stature. It also raises the possibility that not all children with short stature and short mothers have simple 'familial short stature'.