USMLE Step 1 Year: 2024 Number: 1291

Doctors diagnosed a 13-year-old child with retinitis pigmentosa, peripheral polyneuropathy, cerebellar ataxia. Analysis of cerebrospinal fluid showed a high protein content, but not an increase in the number of cells. A significant clinical finding was the high level of serum phytanic acid. These findings indicate which of the following disorders?
carnitine palmitoyltransferase I deficiency
fragile X syndrome
MCAD deficiency
Refsum disease
rhizomelic chondrodysplasia punctata