All five patients had developmental delay, postaxial polydactyly, subtle cleft of the upper lip, hypotonia, and MTS, but notably without renal and retinal anomalies or significant obesity, and they shared the same mutation c.535C>G(p.Q179E) in <i>IFT74</i>, and c.853G>T(p.E285<sup>*</sup>) that we found was a new mutation in <i>IFT74</i> that related with Joubert syndrome. The gene discussed is IFT74; the disease is obesity due to melanocortin 4 receptor deficiency.