VPS35L and Ritscher-Schinzel syndrome: Although this patient was recently diagnosed with VPS35L-associated Ritscher–Schinzel syndrome (OMIM: #618981) based on a previously unrecognized homozygous VPS35L variant74, the patient presents on the severe end of the spectrum of VPS35L-associated phenotypes75 and other genetic factors such as the hypomorphic KLHL4 (p.I287V) variant characterized in this manuscript might therefore contribute to the severity of the phenotype.