トクトミ　トモハル   Tomoharu Tokutomi   徳富　智明    所属   川崎医科大学  医学部 臨床医学　小児科学    職種   特任教授
論文種別	原著
言語種別	英語
査読の有無	査読あり
表題	De novo non-synonymous DPYSL2 (CRMP2) variants in two patients with intellectual disabilities and documentation of functional relevance through zebrafish rescue and cellular transfection experiments.
掲載誌名	正式名：Human molecular genetics
掲載区分	国外
巻・号・頁	31(24),pp.4173-4182
著者・共著者	Hisato Suzuki,Simo Li,Tomoharu Tokutomi,Chisen Takeuchi,Miyuki Takahashi,Mamiko Yamada,Hironobu Okuno,Fuyuki Miya,Toshiki Takenouchi,Hironao Numabe,Kenjiro Kosaki,Toshio Ohshima
発行年月	2022/12/16
概要	Collapsin response mediator protein 2 (Crmp2) is an evolutionarily well-conserved tubulin-binding cytosolic protein that plays critical roles in the formation of neural circuitry in model organisms including zebrafish and rodents. No clinical evidence that CRMP2 variants are responsible for monogenic neurogenic disorders in humans presently exists. Here, we describe two patients with de novo non-synonymous variants (S14R and R565C) of CRMP2 and intellectual disability associated with hypoplasia of the corpus callosum. We further performed various functional assays of CRMP2 variants using zebrafish and zebrafish Crmp2 (abbreviated as z-CRMP2 hereafter) and an antisense morpholino oligonucleotide [AMO]-based experimental system in which crmp2-morphant zebrafish exhibit the ectopic positioning of caudal primary (CaP) motor neurons. Whereas the co-injection of wild-type z-CRMP2 mRNA suppressed the ectopic positioning of CaP motor neurons in Crmp2-morphant zebrafish, the co-injection of R566C or S15R, z-CRMP2, which corresponds to R565C and S14R of human CRMP2, failed to rescue the ectopic positioning. Transfection experiments of zebrafish or rat Crmp2 using plasmid vectors in HeLa cells, with or without a proteasome inhibitor, demonstrated that the expression levels of mutant Crmp2 protein encoded by R565C and S14R CRMP2 variants were decreased, presumably because of increased degradation by proteasomes. When we compared CRMP2-tubulin interactions using co-immunoprecipitation and cellular localization studies, the R565C and S14R mutations weakened the interactions. These results collectively suggest that the CRMP2 variants detected in the present study consistently led to the loss-of-function of CRMP2 protein and support the notion that pathogenic variants in CRMP2 can cause intellectual disabilities in humans.
DOI	10.1093/hmg/ddac166
PMID	35861646