HSD17B10 and Menkes disease: Here, we report a novel variant of the HSD17B10 gene (c.59 C > T) in a boy 2 months and 12 days old with a newly described aspect of the clinical phenotype of HSD10 MD, which manifested as mild developmental delay, metabolic disorders, hyperlactatemia, cholestatic hepatitis, elevated myocardial enzymes and 2M3HBA levels and early death.