Optic Nerve Involvement in Farber Lipogranulomatosis: Expanding the Phenotypic Spectrum

Farber lipogranulomatosis (Farber disease [FD], MIM 228000) is a rare autosomal recessive lysosomal storage disorder caused by a deficiency of acid ceramidase (AC) and is linked to ASAH1 gene mutations. ASAH1 mutations can lead to severe reduction in AC activity that causes accumulation of ceramides in various body tissues including the retina. The onset of clinical manifestations usually occurs during infancy, and the severity depends on residual ceramidase activity. Classic clinical features of FD include painful joint swelling, progressive dysphonia, and subcutaneous nodules. We report 2 unrelated patients presenting with classic FD phenotype who shared the same homozygous pathogenic mutation in the ASAH1 gene and optic neuropathy, thereby expanding the FD phenotypic spectrum.