Refsum disease, an autosomal recessive disorder that results from the accumulation of large stores of phytanic acid in tissues, frequently manifests peripheral polyneuropathy, cerebellar ataxia, retinitis pigmentosa, anosmia, and hearing loss.
The first book introduces Vicki Nelson, a former police officer with failing eyesight due to Retinitis Pigmentosa and Henry Fitzroy, a vampire and writer of historical romances—which is natural for him as he was Henry FitzRoy, 1st Duke of Richmond and Somerset, illegitimate son of Henry VIII before he was seduced by a vampire.
Mutations in the MT-ATP6 gene cause neuropathy, ataxia, and retinitis pigmentosa.