Mutations in BICD2, which Encodes a Golgin and Important Motor Adaptor, Cause Congenital Autosomal-Dominant Spinal Muscular Atrophy

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• 作者：Kornelia Neveling¹ ; ² ; ¹³ ; Lilian A. Martinez-Carrera³ ; ¹³ ; Irmgard Hö ; lker³ ; Angelien Heister¹ ; Aad Verrips⁴ ; Seyyed Mohsen Hosseini-Barkooie³ ; Christian Gilissen¹ ; ² ; ⁵ ; ⁶ ; Sascha Vermeer¹ ; ² ; Maartje Pennings¹ ; Rowdy Meijer¹ ; Margot te Riele⁷ ; Catharina J.M. Frijns⁸ ; Oksana Suchowersky⁹ ; Linda MacLaren¹⁰ ; Sabine Rudnik-Schö ; neborn¹¹ ; Richard J. Sinke¹² ; Klaus Zerres¹¹ ; R. Brian Lowry¹⁰ ; Henny H. Lemmink¹² ; Lutz Garbes³ ; Joris A. Veltman¹ ; ² ; ⁵ ; Helenius J. Schelhaas⁷ ; Hans Scheffer¹ ; ² ; ¹⁴ ; ^{h.scheffer@gen.umcn.nl} ; Brunhilde Wirth³ ; ¹⁴ ; ^{brunhilde.wirth@uk-koeln.de}
• 刊名：The American Journal of Human Genetics
• 出版年：2013
• 出版时间：6 June, 2013
• 年：2013
• 卷：92
• 期：6
• 页码：946-954
• 全文大小：1433 K

文摘

Spinal muscular atrophy (SMA) is a heterogeneous group of neuromuscular disorders caused by degeneration of lower motor neurons. Although functional loss of SMN1 is associated with autosomal-recessive childhood SMA, the genetic cause for most families affected by dominantly inherited SMA is unknown. Here, we identified pathogenic variants in bicaudal D homolog 2 (Drosophila) (BICD2) in three?families afflicted with autosomal-dominant SMA. Affected individuals displayed congenital slowly progressive muscle weakness mainly of the lower limbs and congenital contractures. In a large Dutch family, linkage analysis identified a 9q22.3 locus in which exome sequencing uncovered c.320C>T (p.Ser107Leu) in BICD2. Sequencing of 23 additional families affected by dominant SMA led to the identification of pathogenic variants in one family from Canada (c.2108C>T [p.Thr703Met]) and one from the Netherlands (c.563A>C [p.Asn188Thr]). BICD2 is a golgin and motor-adaptor protein involved in Golgi dynamics and vesicular and mRNA transport. Transient transfection of HeLa cells with all three mutant BICD2 cDNAs caused massive Golgi fragmentation. This observation was even more prominent in primary fibroblasts from an individual harboring c.2108C>T (p.Thr703Met) (affecting the C-terminal coiled-coil domain) and slightly less evident in individuals with c.563A>C (p.Asn188Thr) (affecting the N-terminal coiled-coil domain). Furthermore, BICD2 levels were reduced in affected individuals and trapped within the fragmented Golgi. Previous studies have shown that Drosophila mutant BicD causes reduced larvae locomotion by impaired clathrin-mediated synaptic endocytosis in neuromuscular junctions. These data emphasize the relevance of BICD2 in synaptic-vesicle recycling and support the conclusion that BICD2 mutations cause congenital slowly progressive dominant SMA.