What is MIDD?

Maternally inherited diabetes and deafness (MIDD) is a subtype of mitochondrial disease that is associated with specific inherited mutations in mitochondrial DNA[1]. It accounts for an estimated 1% of diabetes cases[2] and is most common in individuals of Asian descent[3]. As its name suggests, the disorder is almost always accompanied by hearing loss at some point in life[3].

Signs and symptoms of MIDD typically emerge in individuals in their 30s and 40s[4], although it can develop during childhood or late adulthood[2]. Diabetes in MIDD is caused by a shortage of insulin, and individuals with MIDD typically have a low or normal body mass index (BMI)[3]. Hearing loss is progressive, usually precedes the diagnosis of diabetes, and is often more severe in men with MIDD[2].

Current interventions for MIDD can address its symptoms and help affected individuals enjoy a good quality of life.

What causes MIDD?

The most common cause of MIDD is the m.A3243G mutation (located within the MT-TL1 mitochondrial gene). This mutation accounts for approximately 85% of MIDD cases[3].

MIDD can also be caused by mutations in one of the following mitochondrial genes[4]:

The mutations that cause MIDD are inherited from the affected individual’s mother, although de novo cases could occur.

What are the symptoms of MIDD?

Diabetes is the principal symptom of MIDD; most individuals with MIDD also experience hearing loss[2,3].

Some individuals with MIDD may also have[2,3]:

  • muscle cramps or weakness (especially during exercise)
  • heart problems
  • kidney disease
  • constipation
  • short stature
  • potential risk of vision loss due to macular retinal dystrophy*

* = Vision is usually good in individuals with MIDD who have macular retinal dystrophy[4].



How do I know if my loved one has MIDD?

If your loved one has diabetes, a family history of diabetes in maternal relatives, and symptoms associated with other systems of the body (especially hearing), their healthcare provider should consider performing  genetic testing for a MIDD mutation to establish a diagnosis[3].

What are the treatments for MIDD?

Options for managing MIDD include[2,3]:

  • insulin, oral hypoglycemic agents (OHA), and/or diet modification for diabetes
  • angiotensin-converting enzyme inhibitors (ACE-I) and tight blood pressure control for kidney disease
  • cochlear implants for hearing loss

Genetic counseling for the family of the affected individual may also be recommended since MIDD is an inherited disorder.


Are there any clinical trials for MIDD?

To see what trials you may qualify for, visit our Clinical Trials page – which also includes a Clinical Trials Finder Tool. We also highly encourage you to join our patient registry, mitoSHARE, where we are actively recruiting MIDD families.

How can my family cope with MIDD?

We are here to help. UMDF serves many families coping with MIDD. We suggest you reach out to our Support & Education Team – online, via email at support@umdf.org, or phone at (888) 900-6486 – who can suggest a host of resources, including doctors, disease specific support meetings, and more. They’ll also connect you with a UMDF ambassador, likely a fellow MIDD patient or family member, who can help support and guide you through your questions.


What are the next steps if my loved one has MIDD?

  • Get Support
    Connect with our Support & Education Team online, via email at support@umdf.org or phone at (888) 900-6486.
  • Check our Clinical Trials Finder
    Use our Clinical Trials Finder to see if you qualify for any clinical trials.
  • Join our patient registry, mitoSHARE
    We are actively recruiting MIDD families to participate in our patient registry, mitoSHARE. Patient registries like mitoSHARE are an integral part in charting a course toward treatments and cures for MIDD and other mitochondrial diseases. There are currently over 30 active mitochondrial disease clinical trials. Next generation patient registries like mitoSHARE are an integral part of expanding that number.
  • Become an advocate
    Ask your representatives to prioritize mitochondrial disease research and support via the UMDF Advocacy Center. We’ll send regular action items so you – and your friends and family – can let Congress know where we need their support. Click here to sign up.

What is UMDF doing about MIDD?

UMDF is helping chart a path toward treatments and eventual cure of mitochondrial diseases like MIDD through:

  • Research & Funding: UMDF has provided more than $15 million in research funding to find treatments for diseases like MIDD. UMDF advocacy has helped secure an additional $55 million in federal funding via the Department of Defense and National Institutes of Health.
  • Data: Over two decades ago, UMDF pioneered patient registries for the mitochondrial disease community. Today, our next generation patient registry, mitoSHARE, is helping chart a path toward the treatment and eventual cure of mitochondrial diseases.
  • Patient Support: Thousands of families just like you depend upon UMDF for support and education on diseases like MIDD. Attendance at our support meetings annually tops 7,000, including disease specific support meetings for families.
  • Clinician Support: To help educate clinicians on diseases like MIDD, we feature monthly Bench to Bedside clinician seminars, host the annual Mitochondrial Medicine Symposium, support the Mitochondrial Care Network, and educate clinicians on our Mito U platform.

Where can I find more information on MIDD?

I didn’t find what I’m looking for here. What should I do?

UMDF Is here to help. Contact the Support Line at (888) 900-6486 weekdays from 8:00am to 5:00pm EST to connect with our Patient Concierge. Or, via email contact support@umdf.org.


  1. van den Ouweland JM, Lemkes HH, Ruitenbeek W, et al. Mutation in mitochondrial tRNA(Leu)(UUR) gene in a large pedigree with maternally transmitted type II diabetes mellitus and deafness. Nat Genet. 1992;1(5):368-371. doi:10.1038/ng0892-368
  1. Murphy R, Turnbull DM, Walker M, Hattersley AT. Clinical features, diagnosis and management of maternally inherited diabetes and deafness (MIDD) associated with the 3243A>G mitochondrial point mutation. Diabet Med. 2008;25(4):383-399. doi:10.1111/j.1464-5491.2008.02359.x
  1. Yang M, Xu L, Xu C, et al. The Mutations and Clinical Variability in Maternally Inherited Diabetes and Deafness: An Analysis of 161 Patients. Front Endocrinol (Lausanne). 2021;12:728043. Published 2021 Nov 25. doi:10.3389/fendo.2021.728043
  1. Tsang SH, Aycinena ARP, Sharma T. Mitochondrial Disorder: Maternally Inherited Diabetes and Deafness. Adv Exp Med Biol. 2018;1085:163-165. doi:10.1007/978-3-319-95046-4_31