Hereditary Sensory and Autonomic Neuropathy Type III (HSAN III), also known as Familial Dysautonomia (FD) or Riley-Day Syndrome, is a rare genetic disorder that affects the nervous system. It is characterized by a range of symptoms, primarily involving the sensory and autonomic functions of the body.
HSAN III is an autosomal recessive disorder, meaning that an individual must inherit two copies of the defective gene, one from each parent, in order to develop the condition. The condition primarily affects individuals of Ashkenazi Jewish descent.
This neuropathy results in impaired development and functioning of the sensory and autonomic nerves throughout the body. Sensory symptoms include decreased sensitivity to pain and temperature, as well as diminished reflexes. Autonomic symptoms include abnormal regulation of body temperature, blood pressure, and heart rate, resulting in problems with sweating, blood pressure control, and the ability to swallow.
Infants and children with HSAN III may experience difficulty with feeding and failure to thrive. They may also display poor muscle tone, delayed motor skills, and coordination problems. Other possible features of this condition include scoliosis, lung infections, gastrointestinal dysfunction, and impaired intellectual development.
Treatment for HSAN III is mainly symptomatic and supportive, as there is no cure for the condition. Medical management includes monitoring and treating associated complications, such as respiratory infections or feeding difficulties. Physical and occupational therapy may help improve muscle tone, coordination, and mobility. Genetic counseling is also recommended to assist families in understanding the mode of inheritance and options for future pregnancies.
