49,XYYYY syndrome http://purl.bioontology.org/ontology/SNOMEDCT/734028007 A rare Y chromosome number anomaly with a variable phenotype. The main characteristics of this disorder are moderate to severe intellectual disability, speech delay, hypotonia and mild dysmorphic features, including facial asymmetry, hypertelorism, bilateral low set 'lop' ears, and micrognathia. Skeletal abnormalities (such as skull deformities, radioulnar synostosis, elbow flexion, clinodactyly, brachydactyly) have also been associated with this condition. Genitalia are normal at birth, although hypogonadism and azoospermia has been reported in adults. XYYYY syndrome chromosomal gain syndrome 49,XYYYY allosomal chromosomal syndrome