Severe neurodevelopmental impairment in a child with PAX2-related renal Coloboma syndrome: A case report and literature review

PAX2 -related disorders, also known as renal coloboma syndrome, are typically characterized by renal and ocular abnormalities. Although PAX2 expression in the developing central nervous system has been reported, severe neurodevelopmental complications remain rare. We report the case of a male infant referred at 17 months for evaluation of psychomotor developmental delay. He exhibited impaired social interaction, poor eye contact, limited verbal communication, irritability, and feeding difficulties. Renal ultrasonography revealed mild structural abnormalities, and ophthalmological evaluation showed optic nerve anomalies. Genetic analysis identified a novel heterozygous two-base-pair deletion in exon 2 of PAX2 (c.193_194del, p.Val65GlnfsTer36), inherited from his father, who had renal hypoplasia and subtle optic nerve findings. Over time, the patient developed persistent features of autism spectrum disorder and severe developmental delay, although renal function remained stable. This case expands the phenotypic spectrum of PAX2 -related disorders and suggests a potential link to severe neurodevelopmental involvement. Further research is needed to clarify the mechanisms underlying PAX2 -associated neurodevelopmental phenotypes.