Clinical and genetic analysis of a creatine transporter deficiency family / 中华神经科杂志

ABSTRACT

Objective:To report the clinical and genetic characteristics of a family of creatine transporter deficiency (CRTR-D) caused by SLC6A8 gene mutation.Methods:A patient, who came from Department of Neurology, Shanxi Children′s Hospital in September 2018, with epilepsy and unexplained general developmental retardation, was clinically examined. The medical history of his family was also collected. Genetic detection was performed to analyze their genetic causes.Results:The proband, a three years and three months old boy, was walking unsteadily, unable to speak and having frequent seizures, with increased urine creatine/creatinine ratio and decreased peak of cerebral creatine indicated by magnetic resonance spectrum. The proband′s uncle had the similar symptoms with him. The mother of the proband only showed some learning difficulties, while the father, sister and grandparents of the proband had no symptoms. The proband was found to have TTC deletion mutation of SLC6A8 gene (NM_005629), c. 1222_1224del (p.Phe408del), suggestting the diagnosis of X-linked CRTR-D. The proband′s mother and grandmother had heterozygous mutations. The proband′s uncle carried the same hemizygous mutation, which was not detected in the proband′s father, sister or grandfather.Conclusion:In this family of CRTR-D caused by SLC6A8 gene mutation, two female carriers with the same mutation presented different clinical features, suggesting phenotypic variation, which has a great significance in studying the correlation between genotype and phenotype.