Abstract
BACKGROUND: MOMO syndrome is a rare disorder with variable presentation and unknown etiology belonging to the overgrowth syndromes group. CASE PRESENTATION: The authors describe a patient presenting with severe developmental delay, absent speech, autism spectrum disorder, central nervous system malformations, bilateral optic atrophy, and postnatal overgrowth, besides a dysmorphic and progressive coarse face. A clinical diagnosis of MOMO syndrome was proposed, but he developed megaesophagus, megacolon, paraparesis, and severe acne during the clinical follow-up, which are not described in this condition. Whole-genome sequencing detected a deletion of 11.9 Mb at 3q13.2q21.2 comprising 80 genes, including the ZBTB20 gene associated with Primrose syndrome. CONCLUSION: Despite the atypical manifestations in this patient, the overlapping features between MOMO syndrome, Primrose syndrome, and 3q13.31 deletion led the authors to propose that MOMO syndrome could be part of the Primrose/3q13.31 microdeletion syndrome spectrum.