MTTP and retinitis pigmentosa: Deficiencies in fat-soluble vitamins lead to hematological (anemia, acanthocytosis, and increased risk of bleeding), neurological (neuropathy, myopathy, and spinocerebellar ataxia), and ophthalmological manifestations (retinitis pigmentosa) [40], but milder forms of abetalipoproteinemia with fatty liver disease with no neurological, hematological, or ophthalmological manifestations have been reported in the literature, most probably explained by low residual functions of the MTTP protein [41,42].