Familial Dysautonomia (FD) is one example of a group of disorders known as hereditary sensory and autonomic neuropathies (HSAN). The various HSAN disorders are believed to be genetically distinct from each other. Unlike other HSAN, Familial Dysautonomia has been only noted in individuals of Ashkenazi Jewish extraction causing dysfunction of the autonomic and sensory nervous systems. Dysfunction is a result of an incomplete development of the neurons (nerve fibres) of these systems.

For information on Riley-Day syndrome and related dysautonomias see Metabolic diseases.

The most distinctive feature of FD is the absence of overflow tears with emotional crying although it can be normal for a child not to produce tears until seven months of age.

In babies with FD there is a high prevalence of breech presentation births and poor muscle tone (floppy babies).

Other features include:

• a weak or absent suck.
• respiratory congestion due to misdirected swallowing.
• blotching of skin.
• difficulty in maintaining temperature.

Difficulty in feeding is observed in sixty per cent of infants in the neo-natal period. Poor sucking and misdirected swallowing often persist and put the child at risk from aspiration pneumonia which is even more likely to occur if the child also has gastro-oesophageal reflux.

In older children symptoms may include:

• Delay in developmental milestones such as walking and speech.
• Poor balance and unsteady gait.
• Scoliosis (spinal curvature) eighty-five per cent before ten years of age.
• Orthostatic hypotension-extreme drop in blood pressure with change in posture.
• Breath holding until fainting in early years.
• Episodic vomiting.
• Excessive drooling and sweating.
• A smooth tongue and decrease in sense of taste.
• Inappropriate temperature control with very high to very low temperatures.
• Poor weight gain and growth.
• Frequent lung infections.
• Decreased reaction to pain or no reaction at all.
• Cold puffy hands and feet.
• Extremes of blood pressure.
• Corneal abrasions and dry eyes.
• Gastric dysmotility.
• Dysautonomic 'crisis.'

Dysautonomia crisis is a constellation of symptoms that include nausea, high blood pressure, fast heart rate and a change in personality. It is usually caused by stress and that stress can be either physical, such as an infection, or emotional, such as an upcoming exam. Whatever the catalyst, the child will become nauseated, and may start to retch or vomit. In addition there are usually other symptoms including a marked increase in blood pressure and heart rate, sweating, drooling and blotching of the skin. Irritability and a negative personality change also may accompany these symptoms. Episodes can occur as frequently as daily or some patients will never experience a 'crisis.'

The number and severity of symptoms in children are extremely variable. Patients with FD can be expected to function independently if treatment is begun early and major disabilities avoided. Children with FD are usually of normal intelligence. There has been an increased frequency of learning disabilities however. Early intervention and aggressive therapy in areas of language and learning have been extremely successful in prevention and treatment.

Treatment of the condition is symptomatic with emphasis on special therapies (feeding, occupational, physical and speech). The absence of overflow tears requires frequent use of topical lubrication. To cope with the labile blood pressures, periodic gastrointestinal problems and dysautonomic crises, special drug management is required. Surgical interventions may be required to protect the child from respiratory problems that result from misdirecting their swallows. As there is a high incidence of spine curvature, surgery may also be needed for this problem. Due to the decreased taste, temperature and pain perception, the child will need particular protection from injury.

Inheritance patterns
Autosomal recessive. FD has been localised to a gene (IKBKAP) on the long arm of chromosome 9 (9q31).

Prenatal diagnosis
Prenatal diagnosis is available for any couple who are aware that both of them are carriers.

Medical text written January 2002 by Contact a Family. Approved January 2002 by Professor F Axelrod. Last updated September 2006 by Professor F Axelrod, Professor of Dysautonomia Treatment and Research and Professor of Neurology, New York University School of Medicine, New York, USA.

Further Online Resources
Medical texts in The Contact a Family Directory are designed to give a short, clear description of specific conditions and rare disorders. More extensive information on this condition can be found on a range of reliable, validated web sites and links to them are included in the CD-ROM version of this Directory. Further information on these resources can be found in our Medical Information on the Internet article.

US Dysautonomia Foundation:
http://www.familialdysautonomia.org
All medical information on the websiteis approved by Professor F Axelrod, Professor of Dysautonomia Treatment and Research and Professor of Neurology, New York University School of Medicine, New York, USA.

US Familial Dysautonomia Hope Foundation:
http://www.fdhope.org
Funds relevant research programmes, provides a support network aimed at addressing the needs of patients and families, and promotes familial dysautonomia education and awareness programmes.

DYSAUTONOMIA SOCIETY OF GREAT BRITAIN

Dysautonomia Society of Great Britain
PO Box 17679
London
NW4 1WS
Tel: 020 8357 0038
Fax: 020 8958 8760
Web: http://www.dsgb.org

The Society is a National Registered Charity No. 285399, established in 1984. It is mainly a fundraising body but it also offers support by telephone and letter. It has information available, details on request. The families of 12 affected children and adults are in membership.

Group details last updated February 2008.