Autosomal dominant neurodevelopmental disorders associated with KIF1A gene variants in 6 pediatric patients / 浙江大学学报·医学版

OBJECTIVES@#To analyze the clinical and genetic characteristics of children with autosomal dominant neurodevelopmental disorders caused by kinesin family member 1A (KIF1A) gene variation.@*METHODS@#Clinical and genetic testing data of 6 children with KIF1A gene de novo heterozygous variation diagnosed in Shanghai Children's Medical Center Affiliated to Shanghai Jiao Tong University School of Medicine from the year 2018 to 2020 were retrospectively analyzed. Pathogenic variants were identified based on whole exome sequencing, and verified by Sanger sequencing. Moreover, the effect of variants on three-dimensional structure and stability of protein was analyzed by bioinformatics.@*RESULTS@#Among 6 patients there were 4 males and 2 females, and the age of consultation varied from 7 months to 18 years. All cases had varying degrees of motor developmental delay since childhood, and 4 of them had gait abnormalities or fell easily. In addition, 2 children were accompanied by delayed mental development, epilepsy and abnormal eye development. Genetic tests showed that all 6 cases had heterozygous de novo variations of KIF1A gene, including 4 missense mutations c.296C>T (p.T99M), c.761G>A (p.R254Q), c.326G>T (p.G109V), c.745C>G (p.L249V) and one splicing mutation c.798+1G>A, among which the last three variants have not been previously reported. Bioinformatics analysis showed that G109V and L249V may impair their interaction with the neighboring amino acid residues, thereby impacting protein function and reducing protein stability, and were assessed as "likely pathogenic". Meanwhile, c.798+1G>A may damage an alpha helix in the motor domain of the KIF1A protein, and was assessed as "likely pathogenic".@*CONCLUSIONS@#KIF1A-associated neurological diseases are clinically heterogeneous, with motor developmental delay and abnormal gait often being the most common clinical features. The clinical symptoms in T99M carriers are more severe, while those in R254Q carriers are relatively mild.

Hereditary spastic paraplegia with SPG30 mutation: A report from North East China

Hereditary spastic paraplegia is a heterogeneous group of genetic neurodegenerative disorders of the nervous system. It is classified into four subtypes based on the mode of inheritance; and among them, most autosomal recessive hereditary spastic paraplegia cases are due to type SPG11 and SPG15 gene mutations. Autosomal recessive hereditary spastic paraplegia cases with SPG30 gene mutation have never been reported in China. Herein, we present our experience with a case of hereditary spastic paraplegia with SPG30 gene mutation in our hospital from North East China. In this patient we detected a missense mutation of c.499 C>T (p.Arg167Cys) in gene KIF1A, a causative gene of type SPG30.