IMPORTANCE Retinal detachment with avascularity of the peripheral retina, typically associated with familial exudative vitreoretinopathy (FEVR), can result from mutations in KIF11, a gene recently identified to cause microcephaly, lymphedema, and chorioretinal dysplasia (MLCRD) as well as chorioretinal dysplasia, microcephaly, and mental retardation (CDMMR). Ophthalmologists should be aware of the range of presentations for mutations in KIF11 because the phenotypic distinction between FEVR and MLCRD/CDMMR portends management implications in patients with these conditions. OBJECTIVE To identify gene mutations in patients who present with a FEVR phenotype and explore the spectrum of ocular and systemic abnormalities caused by KIF11 mutations in a cohort of patients with FEVR or microcephaly in conjunction with chorioretinopathy or FEVR. DESIGN, SETTING, AND PARTICIPANTS Clinical data and DNA were collected from each participant between 1998 and 2013 from the clinical practices of ophthalmologists and clinical geneticists internationally. Twenty-eight FEVR probands with diagnoses made by the referring physician and without a known FEVR gene mutation, and 3 with microcephaly and chorioretinopathy, were included. At least 1 patient in each pedigree manifested 1 or more of the following: macular dragging, partial retinal detachment, falciform folds, or total retinal detachment.EXPOSURES Whole-exome sequencing was conducted on affected members in multiplex pedigrees, and Sanger sequencing of the 22 exons of the KIF11 gene was performed on singletons. Clinical data and history were collected and reviewed. MAIN OUTCOMES AND MEASURES Identification of mutations in KIF11.RESULTS Four novel heterozygous KIF11 mutations and 1 previously published mutation were identified in probands with FEVR: p.A218Gfs*15, p.E470X, p.R221G, c.790-1G>T, and the previously described heterozygous p.R47X. Documentation of peripheral avascular areas on intravenous fluorescein angiography was possible in 2 probands with fibrovascular proliferation demonstrating phenotypic overlap with FEVR. CONCLUSIONS AND RELEVANCEMutations in KIF11 cause a broader spectrum of ocular disease than previously reported, including retinal detachment. The KIF11 gene likely plays a role in retinal vascular development and mutations in this gene can lead to clinical overlap with FEVR. Cases of FEVR should be carefully inspected for the presence of microcephaly as a marker for KIF11-related disease to enhance the accuracy of the prognosis and genetic counseling.

This large, multicentre study identifies contemporary challenges related to the diagnosis and prognostication of CPVT patients. Structural modelling of RyR2 can improve our understanding severe CPVT phenotypes. Wakeful rest, rather than exertion, often precipitated life-threatening cardiac events.

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