From the Research
Yes, Refsum disease can present first at 50 years of age, although this is uncommon as it is typically diagnosed in childhood or early adulthood. Refsum disease is a rare genetic disorder characterized by the body's inability to properly break down phytanic acid due to a deficiency in the enzyme phytanoyl-CoA hydroxylase. Late-onset cases may present with milder symptoms or a slower progression of the disease. The classic symptoms include retinitis pigmentosa (night blindness and visual field constriction), peripheral neuropathy, cerebellar ataxia, and elevated cerebrospinal fluid protein levels. In adults presenting at age 50, the initial symptoms might be subtle, such as progressive vision problems or unexplained numbness and weakness in the extremities.
Diagnosis and Treatment
Diagnosis involves measuring phytanic acid levels in blood and genetic testing for mutations in the PHYH or PEX7 genes.
- Treatment focuses on dietary restriction of phytanic acid by avoiding foods like dairy products, ruminant animal fats, and certain fish.
- Plasmapheresis may be used in severe cases to rapidly reduce phytanic acid levels.
- Early diagnosis and treatment, even in late-onset cases, can help slow disease progression and manage symptoms effectively, as seen in a case where a 51-year-old patient with Refsum disease showed improved electroretinographic responses following dietary intervention 1.
Key Considerations
- The disease can present with a range of symptoms, including cardiac manifestations, such as arrhythmias or conduction defects, and hypertrophic or dilated cardiomyopathy, leading to heart failure and sudden death 2.
- Current interventions for individuals with Refsum disease consist of dietary phytanic acid restriction and lipid apheresis to control symptoms and enhance quality of life 2.
- The use of the intestinal lipase inhibitor, Orlistat, has been reported as a novel therapeutic approach to reduce phytanic acid levels and retard the progression of symptoms in patients with Refsum disease 3.