Syndromal causes of deafness

The table below summarises some syndromal causes of deafness: not all people who inherit the gene will have all the features and the level of deafness can vary from none at all to profound deafness. Individually, all these syndromes are very rare.

Although the way in which these conditions can be inherited is summarised in the table, the condition can quite often happen for the first time in one person without either parent having the condition themselves. There are many other syndromic causes of deafness, but most are extremely rare.

Many of the investigations that are offered are to rule out these syndromal causes as far as possible. This is to make sure that there are no other health concerns that someone would need to be aware of for the future.

Some of the genes that cause these syndromes are known and, if a genetic test is possible, a genetics doctor might offer this to try and confirm if someone has the condition. The information about genes is not included here because it will become outdated very fast. The genetic counselling clinic will have the most up to date information about genetic testing.

Name	Main features apart from deafness	How it is inherited	Notes
Alport	Kidney problems (blood or protein in urine) which can sometimes progress to kidney failure Harmless changes to back of eye and lens shape	Usually X-linked dominant, but can be autosomal recessive/dominant	X-linked form affects men more than women
Brachio-oto-renal	Abnormal kidney development (small or different shape) that may cause no health problems Outer ear changes: small holes (‘pits’), skin tags or neck cysts	Dominant	As with many dominant conditions, this is very variable
Jervell and Lange-Neilson	One part of heart trace (ECG) known as the ‘QT interval’ is longer than usual. This can cause arhythymia (abnormal rhythm) of the heart which should be monitored and, if necessary, treated	Recessive, but it is important to check the parents’ heart rhythm as well	Pendred Recessive, but it is important to check the parents’ heart rhythm as well
Neurofibromatosis type 2 (NF2)	Hearing loss usually develops as young adults (during 20s and 30s) due to growths on hearing nerve. There is a risk of other benign tumours in the spine or brain which should be monitored	Dominant	This is a very different condition from the more common NF1, which is not a cause of deafness
Pendred	Enlargement of the thyroid gland (goitre). The deafness may progress over time and there can be problems with balance. Part of the inner ear is wider than usual (widened vestibular aqueduct (WVA)) which can be picked up on an MRI or CT scan.	Recessive
Stickler	Severe myopia (short-sightedness) which causes a risk of detached retina. Cataracts. Joint hyperextensibility (double-jointedness). Cleft palate, small chin	Dominant	A very variable condition – not everyone with it has all the features
Treacher Collins	Under-development of the outer ear. Down-slanting eyes. Small jaw	Dominant	A very variable condition
Usher	Progressive visual loss caused by retinitis pigmentosa (literally: developing pigment on the retina). Balance problems	Recessive	Different types vary greatly in the age when visual problems develop and in the level of hearing loss
Waardenburg	Eyes different colour from each other. White patch of hair. Early greying of hair. Eyes can appear widely-spaced	Dominant	A very variable condition

Related articles:

• What can genetics referral offer my family?
• Understanding genetic inheritance
• Genetics of hearing loss
  

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Reproduced with permission.
Date reviewed: 12.11.2008