A patient with Refsum disease may show a number of clinical and laboratory findings associated with accumulation of phytanic acid, a 3-methyl fatty acid.


Onset: may be subtle, ranging from childhood to mid-adult


Ocular and cranial nerve findings:

(1) retinitis pigmentosa

(2) neurogenic hearing loss

(3) anosmia

(4) abnormal pupillary response

(5) miosis

(6) night blindness

(7) decrease in visual acuity and contraction in visual fields progressing to blindness

(8) cataract


Findings in the extremities:

(1) peripheral polyneuropathy, mixed motor and sensory (loss of deep tendon reflexes, paresthesias, anesthesias, dysesthesias, weakness)

(2) marked muscular atrophy

(3) skeletal abnormalities (involving metacarpals, metatarsals, knees, elbows, shoulders)

(4) cerebellar findings which may include ataxic gait or intention tremor


Other findings:

(1) cardiomyopathy with risk of sudden death

(2) ichthyosis


Laboratory findings:

(1) increased concentration of plasma phytanic acid

(2) CSF protein concentration elevated without pleocytosis (albuminocytologic dissociation, total protein >= 100 mg/dL)


Diagnostic tetrad:

(1) retinitis pigmentosa

(2) peripheral polyneuropathy

(3) cerebellar ataxia

(4) high CSF protein


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