The clinical and genetic characteristics of maternally inherited diabetes and deafness (MIDD) with mitochondrial m.3243A > G mutation: A 10‐year follow‐up observation study and literature review

Abstract

Key Clinical MessageMaternally inherited diabetes and deafness (MIDD) is often caused by the m.3243A > G mutation in mitochondrial DNA. Unfortunately, the characteristics of MIDD, especially long‐term outcomes and heteroplasmic changes, have not been well described previously. The purpose of this study was to describe the clinical and genetic features of a family with MIDD after 10 years of follow‐up.A 33‐year‐old male patient with typical characteristics of MIDD, including early‐onset diabetes, deafness, and low body mass index, was admitted to our department. Further investigation revealed that the vast majority of his maternal relatives suffered from diabetes with or without deafness. A detailed family history was then requested from the patient and a pedigree was constructed. The patient suspected of MIDD was screened for mutations using whole mitochondrial DNA sequencing. Candidate pathogenic variants were then validated in other family members through Sanger sequencing. The patient was diagnosed with MIDD, with inherited m.3243A > G mutation in the mitochondrially encoded tRNA leucine 1 (MT‐TL1) gene, after 10 years of symptom onset. The patient was then treated with insulin and coenzyme Q10 to improve mitochondrial function. During the follow‐up period, his fasting blood glucose and HbA1c levels were improved and the incidence of diabetic ketoacidosis was significantly reduced. Our findings indicate that whole mitochondrial DNA sequencing should be considered for patients suspected of MIDD to improve the efficiency of diagnosis and prognosis.

Mitochondrial diabetes plus phenotypes due to the m.3243A > G variant require correlation with heteroplasmy rates

“…We read with interest Zheng et al's article on a family with mitochondrial diabetes due to the mtDNA variant m.3243A > G in MT‐TL1. 1 The index patient, a 33‐year‐old male, exhibited not only diabetes but also hypoacusis, which is why maternally inherited diabetes and deafness (MIDD) syndrome was diagnosed. 1 In addition to MIDD, the index patient suffered from hyperuricemia, abdominal pain, vomiting, myocloni, and limb spams (MIDD plus).…”

“… 1 The index patient, a 33‐year‐old male, exhibited not only diabetes but also hypoacusis, which is why maternally inherited diabetes and deafness (MIDD) syndrome was diagnosed. 1 In addition to MIDD, the index patient suffered from hyperuricemia, abdominal pain, vomiting, myocloni, and limb spams (MIDD plus). 1 The index patient benefited significantly from insulin and coenzyme‐Q.…”

“… 1 In addition to MIDD, the index patient suffered from hyperuricemia, abdominal pain, vomiting, myocloni, and limb spams (MIDD plus). 1 The index patient benefited significantly from insulin and coenzyme‐Q. 1 Six other family members also had MIDD and two additional family members had myocloni.…”

“… 1 The index patient benefited significantly from insulin and coenzyme‐Q. 1 Six other family members also had MIDD and two additional family members had myocloni. 1 The work is compelling, but some points should be discussed.…”