Multilocus pathogenic variants in MCM4, RYR1, and G6PD identified by trio-based whole-exome sequencing in a neonate with multisystem symptoms: a case report

Background: Multilocus pathogenic variants are increasingly recognized in neonates with complex phenotypes and have important implications for diagnosis and clinical management. Reporting such cases helps expand the phenotypic spectrum and improve clinical understanding of blended genetic disorders. Case Description: (c.482G>T, p.Gly161Val), each inherited from one parent. To our knowledge, this combination of variants has not been previously reported. At 18-month follow-up, the infant exhibited delayed motor and language development, unsteady gait, and had 14 hospital visits due to recurrent respiratory infections. Conclusions: This case highlights the potential for blended phenotypes caused by multilocus variation and underscores the diagnostic value of trio-WES in neonates with unexplained multisystem involvement. Long-term follow-up and multidisciplinary management remain essential for such patients.