At birth, individuals with Refsum disease generally appear normal although they may show shorter bones in the hands and feet (metacarpals and metatarsals, respectively). Between 10 and 20 years old, individuals may show their first symptom which is most frequently the loss of night vision (retinitis pigmentosa). Some people may not show any symptoms until up to 50 years of age. Retinitis pigmentosa occurs because light-sensing cells in the retina, a layer in the back of the eye, gradually deteriorate. The initial loss of night vision usually occurs during childhood, and the progression toward loss of peripheral vision and full blindness may occur over the course of years.
Individuals with Refsum disease often present with retinitis pigmentosa and a combination of other symptoms. Other possible issues in the eye include abnormally small pupils, rapid, involuntary eye movement (nystagmus) and cloudiness in the eye that causes individuals to see starburst-type haloes around bright objects (cataracts). Individuals may experience a loss of their sense of smell and taste (anosmia) and after many years, deafness. Affected individuals also may experience numbness, Weakness, a tingling sensation or loss of reflexes in their hands and feet (peripheral polyneuropathy) associated with an unsteady gait (cerebellar ataxia) as they deteriorate. Additionally, individuals with Refsum disease may have rough, scaly patches of skin (ichthyosis) and general Weakness throughout the body. Shortening of bones in the hands and feet and abnormal growth plate formation affecting the knees, shoulders and elbows (skeletal dysplasia) may be seen. Although it is rare, if phytanic acid levels become very high in people with Refsum disease, then a cardiac arrhythmia (irregular heartbeat) can occur which could be life threatening.
The type and number of symptoms present in individuals with Refsum disease varies greatly from person to person and the severity depends on the level of phytanic acid in the body. If a person has a greater build-up of phytanic acid, they are expected to show more severe symptoms. The number and severity of symptoms also may increase with age.