Familial dysautonomia is one example of a group of disorders known as hereditary sensory and autonomic neuropathies, which are characterized by widespread sensory dysfunction and which have been found only in individuals of Ashkenazi Jewish descent.

Familial dysautonomia is associated with irregularities in breathing and sleep structure, such as breath-holding, hypoxia (low oxygen), shortened period of active sleep and increased time to get to active sleep. Some of the symptoms found in babies with the disorder include:

• High prevalence of breech presentation births
• Poor muscle tone
• Weak or absent suck
• Respiratory congestion due to misdirected swallowing
• Blotching of skin
• Difficulty in maintaining temperature

Older children with the disorder might experience:

• Breath holding in early years to the point of fainting
• 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 in blood pressure
• Sudden death

Rush investigators are anticipating that the normal interrelationship of breathing, heart rate and oxygenation will be altered in familial dysautonomia. This altered interrelationship may be a factor in the cause of sudden death among children with familial dysautonomia.

The purpose of this research is to determine the relationship between heart rate, breathing and oxygenation in children with familial dysautonomia, as compared with healthy children without the disorder. The results of this study will provide a more clear description of the phenotype of the autonomic nervous system deficit in familial dysautonomia. If our hypothesis is correct, familial dysautonomia will provide a logical segue to a growing number of diseases that reflect a general dysfunction of the autonomic nervous system (such as, sudden infant death syndrome, congenital central hypoventilation syndrome, and Rett syndrome). Taken together, the results generated by this study will facilitate study into the control of the autonomic nervous system and potential intervention strategies for children with familial dysautonomia, with the long-term goal to decrease the incidence of sudden death.

Children ages 2-18 with a diagnosis of familial dysautonomia with the documented genetic mutation may be eligible to participate in the study. 

Healthy children ages 2-18 with no family history (three generations) of familial dysautonomia, SIDS, Rett syndrome, Hirschsprung disease, apparent life-threatening events in infancy or other disorder of autonomic dysregulation may be eligible as controls. The healthy control subjects will be matched by age, gender and ethnicity to the study subjects with familial dysautonomia.