YIF1B and Kaya-Barakat-Masson syndrome: Two pathogenic homozygous mutations of 2 different neurodevelopmental diseases were reported in two unrelated patients; the first one is a novel mutation c.626A > C (p.Tyr209Ser) in gene YIF1B in one patient of 6 years old with suspected symptoms: developmental regression, hypotonia, spasticity, central hypoventilation, poor eye contact, absence of speech, seizures, and brain abnormalities of Kaya-Barakat-Masson syndrome.