Background: IFIH1 is a protein-coding gene. Disorders associated with IFIH1 include Aicardi-Goutières syndrome (AGS) type 7 and Singleton-Merten syndrome type 1. Related pathways include RIG-I/MDA5-mediated induction of the interferon (IFN)-α/β pathway and the innate immune system. AGS type 7 is an autosomal dominant inflammatory disorder characterized by severe neurological impairment. In infancy, most patients present with psychomotor retardation, axial hypotonia, spasticity, and brain imaging changes Laboratory assessments showed increased IFN-α activity with upregulation of IFN signaling and IFN-stimulated gene expression. Some patients develop normally in the early stage, and then have episodic neurological deficits.
Case summary: The 5-year-old girl presented with postpartum height and weight growth retardation, language retardation, brain atrophy, convulsions, and growth hormone deficiency. DNA samples were obtained from peripheral blood from the child and her parents for whole-exome sequencing and test of genome-wide copy number variation. Heterozygous mutations in the IFIH1 gene were found. Physical examination at admission found that language development was delayed, the reaction to name calling was average, there was no communication with people, but there was eye contact, no social smile, and no autonomous language. However, the child had rich gesture language and body language, could understand instructions, had bad temper. When she wants to achieve something, she starts crying or shouting. Cardiopulmonary examination showed no obvious abnormality, and abdominal examination was normal. Bilateral muscle strength and muscle tone were symmetrical and slightly decreased. Physiological reflexes exist, but pathological reflexes were not elicited.
Conclusion: We reported the clinical characteristics of a Chinese child with a clinical diagnosis of AGS type 7, which expanded the mutational spectrum of the IFIH1 gene.
Keywords: Aicardi-Goutières syndrome type 7; Case report; Children; IFIH1 gene.
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