Objective: To analyze the clinical phenotype and genetic variants of a child with X-linked mental retardation caused by IQSEC2 gene mutation, and provide reference for the diagnosis of the disease.
Methods: The child was subjected to next generation sequencing (NGS), and the diagnosis was made by taking consideration of her clinical characteristics.
Results: The child has presented with global developmental delay, particularly in fine motor skill and language development, in addition with intellectual disability. Genetic testing revealed that she has harbored a heterozygous c.1861dup variant of the IQSEC2 gene, which was not detected in either parent.
Conclusion: The de novo c.186ldup variant of the IQSEC2 gene probably underlay the X-linked mental retardation in this child. Above finding has, expanded the spectrum of IQSEC2 gene mutations and provide a basis for the diagnosis of similar cases.