Identification of a novel and a recurrent CDC45 variant in a Chinese family with Meier-Gorlin syndrome 7 and a literature review

Abstract

Meier-Gorlin syndrome 7 (MGORS7) is a rare autosomal recessive disorder characterized by primordial dwarfism, craniosynostosis, and patellar aplasia, caused by pathogenic variants of CDC45 . Here, we report a Chinese patient presenting with classic hallmarks of MGORS7 alongside atypical clinical features, including hearing and visual impairments. Clinical and radiological data were collected. Whole-genome sequencing and Sanger sequencing were performed to identify and validate the causative variants. Their functional effects were investigated using an exon-trapping assay, and a literature review of previously reported MGORS7 cases was conducted. Genetic analysis identified two compound heterozygous CDC45 variants: c.1416C>T (p.H472=) and c.1559+2T>A, which are a recurrent variant in the East Asian population and a novel variant, respectively. Our exon-trapping assay indicated that c.1559+2T>A induced aberrant splicing, generating transcripts predicted to undergo nonsense-mediated mRNA decay. Additionally, growth hormone therapy was initiated in our patient, with a noted improvement in growth parameters in the initial assessment and without immediate complications. The literature review identified a total of 32 CDC45 variants in 29 patients with MGORS7, who showed high heterogeneity in clinical phenotypes. Our study further expanded the mutational spectrum of CDC45 and provided a preliminary clinical observation suggesting that growth hormone therapy may be beneficial for growth retardation in patients with MGORS7.