| Subject | Contents |
| Definition | An inherited disorder that affects sensory and autonomic nerve function in many body parts/systems. |
| Alternative Names | Familial dysautonomia; Hereditary sensory and autonomic neuropathy - type III |
| Causes, incidence, and risk factors | Riley-Day syndrome is inherited as an autosomal recessive trait that is found predominantly in the European Jewish population (Ashkenazi Jews). The disease is caused by mutation of the IKBKAP gene on chromosome 9. It is not rare in Ashkenazi Jews where the incidence is estimated to be 1 in 3700 people. Infants with this condition have feeding problems and develop pneumonia caused by inhalation of their formula and food. Episodic vomiting and sweating spells begin following infancy. Young children also have breath-holding spells that produce unconsciousness . Insensitivity to pain is a hallmark of Riley-Day syndrome and leads to unnoticed injuries or injuries that might not have occurred had the child sensed discomfort. Children do not feel the normal sensations that generally warn of impending injury such as drying of the eyes, pressure over pressure points, and chronic rubbing and chaffing. Seizures may occur in almost 50% of affected children. They have postural hypotension or hypertensive crises. Temperature regulation may be deficient. |
| Symptoms | a family history of Riley-Day syndrome Ashkenazi Jewish heritage feeding difficulties -- poor sucking and poor ability to swallow, drooling breath holding sweating while eating protracted episodes of vomiting lack of response to painful stimuliseizureshypotonia , low muscle tone abnormal body temperature (high or low) abnormally high blood pressure that is intermittent incoordination, unsteady gait an unusually smooth tongue surface (due to absence of fungiform papillae) |
| Signs and tests | repeat aspiration pneumonia cyclic vomitingunsteady gait delayed puberty speech abnormalities corneal damage due to lack of tearing and blink reflex, gentle touching cornea with 'Q-Tip' won't produce a blink absent or decreased deep tendon reflexes insensitivity to pain normal intellect Tests: X-ray of the chest showing signs of recurrent aspiration pneumonia VMA - decreased HVA - elevated absence of flare response to histamine (Normally when histamine is injected just under the skin there will be swelling and redness. If there is a lack of this flair response or swelling/redness, the test is positive i.e., indicates Riley-Day syndrome.) abnormal heart rhythm on ECG DNA testing can be done by linkage analysis or direct mutation testing |
| Treatment | Protection from injury is critical. Problems are treated as they occur, including treatment of aspiration pneumonia , anticonvulsant therapy if seizures are present, and liquid tears and bethanechol to prevent drying of eyes. Antiemetics may be used to control vomiting |
| Support Groups | Familial Dysautonomia Hope, Inc. 847-913-9377 |
| Expectations (prognosis) | Most people with this syndrome do not live to normal life expectancy. A person who lives into their 40s is old for a Riley-Day syndrome patient. Half of patients do not survive past 20 years of age. |
| Complications | Charcot joints from repeated injury increased incidence of diabetes mellitus phobias and emotional disorders |
| Calling your health care provider | Call your health care provider if you have a family history of Riley-Day syndrome and are planning to have a child or expecting a child. If you are unsure of your family history but belong to a high risk population it may be helpful to consult a genetic counselor. |
| Prevention | Genetic counseling is recommended for prospective parents if there is a family history of Riley-Day syndrome. |
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