title: Delineation of the clinical, molecular and cellular aspects of novel JAM3 mutations underlying the autosomal recessive hemorrhagic destruction of the brain, subependymal calcification, and congenital cataracts.
abstract: We have recently shown that the hemorrhagic destruction of the brain, subependymal, calcification, and congenital cataracts is caused by biallelic mutations in the gene encoding junctional adhesion molecule 3 (JAM3) protein. Affected members from three new families underwent detailed clinical examination including imaging of the brain. Affected individuals presented with a distinctive phenotype comprising hemorrhagic destruction of the brain, subependymal calcification, and congenital cataracts. All patients had a catastrophic clinical course resulting in death. Sequencing the coding exons of JAM3 revealed three novel homozygous mutations: c.2T>G (p.M1R), c.346G>A (p.E116K), and c.656G>A (p.C219Y). The p.M1R mutation affects the start codon and therefore is predicted to impair protein synthesis. Cellular studies showed that the p.C219Y mutation resulted in a significant retention of the mutated protein in the endoplasmic reticulum, suggesting a trafficking defect. The p.E116K mutant traffics normally to the plasma membrane as the wild-type and may have lost its function due to the lack of interaction with an interacting partner. Our data further support the importance of JAM3 in the development and function of the vascular system and the brain.
authors.affiliation: Department of Pathology, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates.
authors.forename: Nadia A
authors.initials: NA
authors.lastname: Akawi
authors.forename: Fuat E
authors.initials: FE
authors.lastname: Canpolat
authors.forename: Susan M
authors.initials: SM
authors.lastname: White
authors.forename: Josep
authors.initials: J
authors.lastname: Quilis-Esquerra
authors.forename: Martin
authors.initials: M
authors.lastname: Morales Sanchez
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Gamundi
authors.forename: Ganeshwaran H
authors.initials: GH
authors.lastname: Mochida
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Walsh
authors.forename: Bassam R
authors.initials: BR
authors.lastname: Ali
authors.forename: Lihadh
authors.initials: L
authors.lastname: Al-Gazali
mesh_terms: D001315:Australia; D001921:Brain / Q000473:pathology*; D002114:Calcinosis / Q000235:genetics*; D002386:Cataract / Q000151:congenital* / Q000235:genetics*; D015815:Cell Adhesion Molecules / Q000172:deficiency / Q000235:genetics*; D002543:Cerebral Hemorrhage / Q000235:genetics*; D005091:Exons; D005260:Female; D006367:HeLa Cells; D006720:Homozygote; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D008297:Male; D018613:Microscopy, Confocal; D020125:Mutation, Missense; D010375:Pedigree; D010641:Phenotype; D017422:Sequence Analysis, DNA; D013030:Spain; D014421:Turkey; D014479:United Arab Emirates
chemical_list: D015815:Cell Adhesion Molecules; C448000:JAM3 protein, human