Received: 12 May 2017 Revised: 20 June 2017 Accepted: 28 June 2017 DOI: 10.1002/humu.23286 BRIEF REPORT BOC is a modifier gene in holoprosencephaly Mingi Hong1∗ Kshitij Srivastava2∗ Sungjin Kim1 Benjamin L. Allen3 Daniel J. Leahy4 Ping Hu2 Erich Roessler2 Robert S. Krauss1† Maximilian Muenke2† 1Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York 2Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 3Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 4Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas Correspondence Robert S. Krauss (for editorial communication), Abstract Department of Cell, Developmental and Regen- Holoprosencephaly (HPE), a common developmental defect of the forebrain and midface, has a erative Biology, Icahn School of Medicine at complex etiology. Heterozygous, loss-of-function mutations in the sonic hedgehog (SHH) pathway Mount Sinai, New York, New York 10029. Email:
[email protected] are associated with HPE. However, mutation carriers display highly variable clinical presentation, Maximilian Muenke, Medical Genetics Branch, leading to an “autosomal dominant with modifier” model, in which the penetrance and expressiv- National Human Genome Research Institute, ity of a predisposing mutation is graded by genetic or environmental modifiers. Such modifiers National Institutes of Health, Bethesda, Mary- land 20892. have not been identified. Boc encodes a SHH coreceptor and is a silent HPE modifier gene in mice. Email:
[email protected] Here, we report the identification of missense BOC variants in HPE patients. Consistent with these ∗Mingi Hong and Kshitij Srivastava contributed alleles functioning as HPE modifiers, individual variant BOC proteins had either loss- or gain-of- equally to this work.