1q25.3-q32.1 deletion causing multisystem developmental delay: a case report and literature review.

Objective: This study provides a detailed report of a pediatric patient with a 1q25.3-q32.1 deletion, reports the results of a retrospective analysis of relevant literature, and examines relevant genotype-phenotype correlations. Its objectives are to enhance clinicians' awareness of this rare disorder and to provide clinical evidence for genotype-phenotype correlation analysis. Methods: We collected clinical data from one case of 1q25.3-q32.1 deletion, including perinatal history, clinical manifestations, auxiliary examinations, diagnosis and treatment, and follow-up information, and conducted analysis. Simultaneously, we searched literature databases, including PubMed, Embase, the China National Knowledge Infrastructure, and Wanfang, to collect domestic and international papers on 1q25-q32 deletions published up to January 2025. Clinical characteristics, genetic information, and prognostic data from these case reports were extracted and compiled to analyze genotype-phenotype associations. Results: A male newborn was born at 37 weeks' gestation with intrauterine growth restrictions. Neonatal presentation included feeding difficulties and decreased spontaneous activity. Karyotype analysis showed 46,XY,del(1)(q23.3q25.3). Chromosomal microarray analysis revealed a pathogenic 27.0-Mb deletion in the 1q25.3-q32.1 region. Follow-up revealed persistent postnatal growth and motor developmental delays, along with language development delays, in the patient. A literature review yielded 31 cases (including this case) of 1q25-q32-deletion syndrome. Primary common clinical features included intrauterine growth restriction, postnatal growth retardation, microcephaly, facial dysmorphism, neurological abnormalities, delayed motor and language development. The deleted segment ranged from 1.5 to 28.0 Mb in size. Key genes within the deleted region (e.g., Conclusion: Deletion of 1q25.3-q32.1 is a rare chromosomal rearrangement associated with corresponding phenotypic features. When children present with intellectual disability, intrauterine growth restriction, postnatal growth retardation, language developmental delays, motor developmental delays, microcephaly, facial dysmorphisms, small hands and feet, external genital anomalies, brachydactyly, and clinodactyly of the fifth finger, clinicians should highly suspect 1q intermediate chromosome deletion. It is recommended to perform chromosomal microarray analysis (CMA) as early as possible to establish a clear diagnosis, and implement individualized intervention and long-term follow-up so as to improve the prognosis. This report illustrates how molecular delineation associated with fine clinical characterization can improve the genotype-phenotype correlations of classical cytogenetic abnormalities.