Clinical report and genetic analysis of a novel variant in ZMIZ1 causing neurodevelopmental disorder with dysmorphic factors and distal skeletal anomalies in a Chinese family.

Background: Neurodevelopmental disorder with dysmorphic factors and distal skeletal anomalies (NEDDFSA) is a rare and phenotypically variable disorder. The zinc finger MIZ-type containing 1 gene (ZMIZ1) is a causative gene of NEDDFSA that encodes a protein inhibitor of the activated STAT-like family transcriptional regulator. Given the rarity of reported NEDDFSA cases, new phenotypes and genotypes of this disorder are still being discovered.

Objective: This study describes the phenotype characteristics of a Chinese NEDDFSA family caused by a novel ZMIZ1 variant.

Methods: We reviewed the clinical phenotype of a Chinese patient with NEDDFSA and performed whole-exome sequencing (WES) of the patient's family. We simulated the potential biological harmfulness of the mutant protein. Plasmids were constructed and used for western blot and immunofluorescence assays to analyze protein expression levels.

Results: The patient was a 6-month-old male infant who exhibited dysmorphic facial features, neurodevelopmental abnormalities, congenital heart disease, and previously unreported genitourinary system anomalies. WES revealed a non-frameshift deletion variant in ZMIZ1 (NM_020338.4: c.858_875del, p.Val288_Ala293del), resulting in a structural alteration in the protein's alanine-rich domain. Western blot and immunofluorescence assays indicated a significant decrease in the expression level of the mutant ZMIZ1 protein compared to the wild-type protein.

Conclusion: The clinical manifestations of this patient may be associated with the ZMIZ1 variant, and the structural alteration in the alanine-rich domain of the ZMIZ1 protein may contribute to a more complex disease phenotype. These results expand the genotype-phenotype correlation of ZMIZ1.