Analysis of a family with early-onset dementia caused by a new mutation in the triggerring receptor expressing on myeloid cells 2 gene / 中华神经科杂志

ABSTRACT

Objective:To analyze the clinical phenotype, imaging characteristics and genetic characteristics of a family of early-onset dementia caused by a new mutation in the triggerring receptor expressing on myeloid cells 2 gene (TREM2).Methods:Clinical data were collected from a patient with early-onset dementia. Then whole exome sequencing was performed for the proband, followed by Sanger sequencing for the family members.Results:The clinical manifestations of the proband (a 49-year-old female) was personality changes, mental and behavioral abnormalities, memory loss, ataxia, and seizures. Whole-exon sequencing revealed a novel homozygous mutation in exon 2 of TREM2, namely c.154C>T (p.R52C) heterozygosity in four family members, and one patient with similar clinical manifestations was deceased. The proband′s brain magnetic resonance imaging showed bilateral frontotemporal atrophy, bilateral white matter hyperintensity, thin corpus callosum. No bone cysts of the hands and feet were found by digital radiographic imaging.Conclusions:A homozygous mutation in TREM2 gene was detected in a patient with frontotemporal dementia-like dementia, epilepsy, but without bone cysts. This mutation is probably pathogenic. This research highlights the importance of TREM2 gene mutation screening in early-onset dementia, especially in those with atypical presentations.