According with our results, the presence of the high-risk haplotypes (homozygous for MTHFR) should be considered in diagnosing the severity of LCPD, as up to 50% (two out of four) of the patients had Stulberg IV–V outcomes (three out of four in children under 6 years old). Here, MTHFR is linked to Legg-Calve-Perthes disease.