DOORS syndrome

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Reviewed December 2015

What is DOORS syndrome?

DOORS syndrome is a disorder involving multiple abnormalities that are present from birth (congenital). "DOORS" is an abbreviation for the major features of the disorder including deafness; short or absent nails (onychodystrophy); short fingers and toes (osteodystrophy); developmental delay and intellectual disability (previously called mental retardation); and seizures. Some people with DOORS syndrome do not have all of these features.

Most people with DOORS syndrome have profound hearing loss caused by changes in the inner ears (sensorineural deafness). Developmental delay and intellectual disability are also often severe in this disorder.

The nail abnormalities affect both the hands and the feet in DOORS syndrome. Impaired growth of the bones at the tips of the fingers and toes (hypoplastic terminal phalanges) account for the short fingers and toes characteristic of this disorder. Some affected individuals also have an extra bone and joint in their thumbs, causing the thumbs to look more like the other fingers (triphalangeal thumbs).

The seizures that occur in people with DOORS syndrome usually start in infancy. The most common seizures in people with this condition are generalized tonic-clonic seizures (also known as grand mal seizures), which cause muscle rigidity, convulsions, and loss of consciousness. Affected individuals may also have other types of seizures, including partial seizures, which affect only one area of the brain and do not cause a loss of consciousness; absence seizures, which cause loss of consciousness for a short period that appears as a staring spell; or myoclonic seizures, which cause rapid, uncontrolled muscle jerks. In some affected individuals the seizures increase in frequency and become more severe and difficult to control, and a potentially life-threatening prolonged seizure (status epilepticus) can occur.

Other features that can occur in people with DOORS syndrome include an unusually small head size (microcephaly) and facial differences, most commonly a wide, bulbous nose. A narrow or high arched roof of the mouth (palate), broadening of the ridges in the upper and lower jaw that contain the sockets of the teeth (alveolar ridges), or shortening of the membrane between the floor of the mouth and the tongue (frenulum) have also been observed in some affected individuals. People with DOORS syndrome may also have dental abnormalities, structural abnormalities of the heart or urinary tract, and abnormally low levels of thyroid hormones (hypothyroidism). Most affected individuals also have higher-than-normal levels of a substance called 2-oxoglutaric acid in their urine; these levels can fluctuate between normal and elevated.

How common is DOORS syndrome?

DOORS syndrome is a rare disorder; its prevalence is unknown. Approximately 50 affected individuals have been described in the medical literature.

What genes are related to DOORS syndrome?

DOORS syndrome can be caused by mutations in the TBC1D24 gene. This gene provides instructions for making a protein whose specific function in the cell is unclear. Studies suggest the protein may have several roles in cells. The TBC1D24 protein belongs to a group of proteins that are involved in the movement (transport) of vesicles, which are small sac-like structures that transport proteins and other materials within cells. Research suggests that the TBC1D24 protein may also help cells respond to oxidative stress. Oxidative stress occurs when unstable molecules called free radicals accumulate to levels that can damage or kill cells. Studies indicate that the TBC1D24 protein is active in a variety of organs and tissues; it is particularly active in the brain and likely plays an important role in normal brain development. The TBC1D24 protein is also active in specialized structures called stereocilia. In the inner ear, stereocilia project from certain cells called hair cells. The stereocilia bend in response to sound waves, which is critical for converting sound waves to nerve impulses.

TBC1D24 gene mutations that cause DOORS syndrome are thought to reduce or eliminate the function of the TBC1D24 protein, but the specific mechanism by which loss of TBC1D24 function leads to the signs and symptoms of DOORS syndrome is not well understood.

In about half of affected individuals, no TBC1D24 gene mutation has been identified. The cause of DOORS syndrome in these individuals is unknown.

How do people inherit DOORS syndrome?

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Where can I find information about diagnosis or management of DOORS syndrome?

These resources address the diagnosis or management of DOORS syndrome and may include treatment providers.

Gene Review: TBC1D24-Related Disorders

You might also find information on the diagnosis or management of DOORS syndrome inEducational resources and Patient support.

General information about the diagnosis and management of genetic conditions is available in the Handbook.

To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.

Where can I find additional information about DOORS syndrome?

You may find the following resources about DOORS syndrome helpful. These materials are written for the general public.

MedlinePlus - Health information (7 links)
Additional NIH Resources - National Institutes of Health
National Institute of Neurological Disorders and Stroke: Epilepsy Information Page
Educational resources - Information pages (2 links)
Patient support - For patients and families (6 links)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

Gene Reviews - Clinical summary
PubMed - Recent literature
OMIM - Genetic disorder catalog

What other names do people use for DOORS syndrome?

autosomal recessive deafness-onychodystrophy syndrome
deafness-oncychodystrophy-osteodystrophy-intellectual disability syndrome
deafness, onychodystrophy, osteodystrophy, and mental retardation syndrome
deafness-onychoosteodystrophy-intellectual disability syndrome
digitorenocerebral syndrome
DOOR syndrome
DRC syndrome
Eronen syndrome

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines and How are genetic conditions and genes named? in the Handbook.

What if I still have specific questions about DOORS syndrome?

Ask the Genetic and Rare Diseases Information Center

Where can I find general information about genetic conditions?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding DOORS syndrome?

autosomal ; autosomal recessive ; cell ; congenital ; developmental delay ; disability ; free radicals ;frenulum ; gene ; hair cells ; hypothyroidism ; inherited ; joint ; lower jaw ; mental retardation ;microcephaly ; mutation ; oxidative stress ; palate ; prevalence ; protein ; recessive ; seizure ;sensorineural ; status epilepticus ; stress ; syndrome ; thyroid ; thyroid hormones

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

References (4 links)

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook