FD results in variable symptoms, including insensitivity to pain, inability to produce tears, poor growth, and labile blood pressure (episodic hypertension and postural hypotension).

People with FD have frequent vomiting crises, pneumonia, problems with speech and movement, difficulty swallowing, and inappropriate perception of heat, pain, and taste, as well as unstable blood pressure and gastrointestinal dysmotility.

Conrad Milton Riley and Richard Lawrence Day in 1949,[4] FD is one example of a group of disorders known as hereditary sensory and autonomic neuropathies (HSANs).

Signs and symptoms of familial dysautonomia usually commence during infancy and worsen with age, and may include gastrointestinal dysmotility (including erratic gastric emptying, gastroesophageal reflux, abnormal esophageal peristalsis, oropharyngeal incoordination),[3] dysphagia (as poor suckling in infancy) and frequent choking/gagging, recurrent vomiting, poor weight gain[6]/growth,[7] delayed development (especially walking) and puberty (especially in girls), recurrent aspiration pneumonia (due to inhalation of food or vomitus)[6] with possible secondary chronic lung disease,[3] absence of overflow tears during crying, corneal ulcers, red skin blotches and excessive sweating (often during eating or excitement), breath-holding spells, slurred speech/nasal voice, tongue ulcers (from accidental self-injuries), hyporeflexia (variable absence of deep tendon reflexes[8]), hypotonia, enuresis, arrhythmias, hypertension (including episodic hypertension in response to emotional stress or visceral pain[3]), hypotension (including orthostatic hypertension[7] with compensatory tachycardia (invariably present)[3]),[6] impaired (but not absent[3]) temperature and pain perception (leading to frequent accidental injury),[2][6] impaired proprioception, a smooth glossy tongue,[6] scoliosis (with possibly secondary restrictive lung disease[3]),[7] abnormal gait,[9] short stature, chronic renal failure (common), visual impairment, variable cognitive ability, characteristic facial features that develop with time, impaired vibration perception, lack of fungiform papilla of the tongue,[3] and impaired taste perception (especially for sweetness).

During the neonatal period, hypotonia, respiratory insufficiency, poor feeding with difficulty swallowing and aspiration, developmental delay, short stature, scoliosis, and corneal disease may occur.

[7] In school-age children, bed wetting, vomiting episodes, impaired pain, and temperature perception, impaired blood pressure control (including orthostatic hypotension, hypertension during periods of psychological excitement or vomiting), learning disabilities (e.g. short attention span; learning disabilities are present in about a third of those with FD, and may require special education), scoliosis, poor bone quality and bone fractures, and kidney and heart issues may be seen.

Conversion of T→C in intron 20 of the donor gene resulted in shift splicing that generates an IKAP transcript lacking exon 20.

[13] Familial dysautonomia is inherited in an autosomal recessive pattern, which means two copies of the gene in each cell are altered.

[citation needed] Other issues that can be treated include FD crises, scoliosis, and various eye conditions due to limited or no tears.

Common management strategies include artificial tears, appropriate feeding strategy (maintenance of adequate nutrition, avoidance of aspiration (thickened formula and differently shaped nipples[further explanation needed] for infants)), daily chest physiotherapy (nebulization, bronchodilators, and postural drainage) for chronic pulmonary disease, pharmaceutical management of autonomic features (e.g. intravenous or rectal diazepam, or rectal chloral hydrate), preventing accidental injury, prevention of orthostatic hypotension (hydration, leg exercise, frequent small meals, a high-salt diet, and medication (e.g. with fludrocortisone)), treatment of orthopedic problems, compensating labile blood pressure.

[citation needed] Parents and patients should be informed regarding daily eye care and early signs of corneal problems, as well as punctal cautery.

[citation needed] The survival rate and quality of life have increased since the mid-1980s, mostly due to a greater understanding of the most dangerous symptoms.

At present, FD patients can be expected to function independently if treatment is begun early and if major disabilities are avoided.

[17] In January 2001, researchers at Fordham University and Massachusetts General Hospital simultaneously reported finding the genetic mutation that causes FD, a discovery that opens the door to many diagnostic and treatment possibilities.