There is also wider significance to our observations: HCCS mutation in humans causes microphthalmia with linear skin lesions (MLS) (22, 23), but insight into HCCS catalysis, and thus the mechanistic consequence(s) of HCCS mutation, are in their infancy (13, 24, –, 26). Here, HCCS is linked to McLeod neuroacanthocytosis syndrome.