Case Report: Non-ossifying fibromas with pathologic fractures in a patient with NONO-associated X-linked syndromic intellectual developmental disorder

The NONO gene encodes a nuclear protein involved in transcriptional regulation, RNA synthesis and DNA repair. Hemizygous loss-of function, de novo or maternally inherited variants have been associated with an X-linked syndromic intellectual developmental disorder-34 (OMIM # 300967), characterized by delay, disability, hypotonia, macrocephaly, elongated face, structural abnormalities of corpus callosum and/or cerebellum, congenital heart defect left ventricular non-compaction cardiomyopathy. Few patients described the literature phenotype data are limited. We report 17-year-old boy dolihocephaly, strabismus, speech motor (ASD, VSD Ebstein’s anomaly), cardiomyopathy, bilateral inguinal hernia cryptorchidism. Additional features included recurrent fractures due to multiple non-ossifying fibromas, thrombocytopenia, renal anomalies. Exome sequencing revealed pathogenic variant (NM_001145408.2: c.348+2_ 348+15del) intron 5 gene. Renal anomalies thrombocytopenia rarely reported —X-linked disability syndrome, while fibromas not previously this syndrome. phenotypic spectrum syndrome may be broader than currently known.