Maternal Diabetes

Maternal diabetes, meaning the mother has diabetes, can sometimes lead to inherited diabetes and deafness.

Diabetes is a disease that is characterized by persistent elevations in the body's blood sugar levels. This condition can sometimes result in damage of the eyes, heart, kidneys, and nerves. About 3-percent of people who have diabetes inherited the disease from their mothers, along with hearing loss or deafness. This rare form of diabetes is known as maternally inherited diabetes and deafness (MIDD) and it can be the result of specific genetic defects in the mechanisms that usually produce energy for your body.

Information about MIDD is pretty scarce because so few people suffer from this form of diabetes. The medical profession is constantly trying to study and understand genetic defects of this type. However, nearly all of the human genes can be found in the nucleus of the cell on one of the 23 chromosome pairs. There are other genes on the tiny chromosomes in the mitochondria of the cell though. Mutations in these mitochondrial chromosomes have recently been found to be associated with various types of hearing impairments. Mitochondrial DNA can only be transmitted through the mother as a man's sperm apparently contributes no mitochondrial DNA. This means that a defect in a mitochondrial gene should lead to disease in both males and females, but it can only be transmitted through the mother.

Hearing impairment has been found to be linked to an assortment of different mitochondrial defects. A diagnosis of MIDD should be considered when diabetic people show the following characteristics:

• Relatively young age at onset
• Normal to low body weight
• Deafness or hearing loss
• Characteristic eye findings known as macular pattern dystrophy

Diabetes and deafness can occur together in various syndromes including diabetes insipidus, diabetes mellitus, optic atrophy and deafness (DIDMOAD), thiamine-responsive megaloblastic anaemia and mitochondrial diabetes. The onset of diabetes can occur at any age and the hearing loss may come relatively late in onset. However, deafness generally precedes diabetes. On average, most people who have maternally inherited diabetes and deafness were young at the onset of diabetes and have a normal or low body mass index.