@article {237, title = {Mutations in COL27A1 cause Steel syndrome and suggest a founder mutation effect in the Puerto Rican population.}, journal = {Eur J Hum Genet}, volume = {23}, year = {2015}, month = {2015 Mar}, pages = {342-6}, abstract = {

Osteochondrodysplasias represent a large group of developmental structural disorders that can be caused by mutations in a variety of genes responsible for chondrocyte development, differentiation, mineralization and early ossification. The application of whole-exome sequencing to disorders apparently segregating as Mendelian traits has proven to be an effective approach to disease gene identification for conditions with unknown molecular etiology. We identified a homozygous missense variant p.(Gly697Arg) in COL27A1, in a family with Steel syndrome and no consanguinity. Interestingly, the identified variant seems to have arisen as a founder mutation in the Puerto Rican population.

}, keywords = {Amino Acid Sequence, Child, Preschool, Comparative Genomic Hybridization, Exome, Female, Fibrillar Collagens, Follow-Up Studies, Founder Effect, Genotype, Hispanic Americans, Humans, Infant, Male, Molecular Sequence Data, Mutation, Osteochondrodysplasias, Pedigree, Polymorphism, Single Nucleotide, Prostaglandins F, Puerto Rico, Sequence Alignment}, issn = {1476-5438}, doi = {10.1038/ejhg.2014.107}, author = {Gonzaga-Jauregui, Claudia and Gamble, Candace N and Yuan, Bo and Penney, Samantha and Jhangiani, Shalini and Muzny, Donna M and Gibbs, Richard A and Lupski, James R and Hecht, Jacqueline T} } @article {216, title = {New mutations in the RAB28 gene in 2 Spanish families with cone-rod dystrophy.}, journal = {JAMA Ophthalmol}, volume = {133}, year = {2015}, month = {2015 Feb}, pages = {133-9}, abstract = {

IMPORTANCE: The families evaluated in this study represent the second report of cone-rod dystrophy (CRD) cases caused by mutations in RAB28, a recently discovered gene associated with CRD.

OBJECTIVE: To determine the disease-causing gene in 2 families of Spanish descent presenting with CRD who do not have ABCA4 mutations.

DESIGN, SETTING, AND PARTICIPANTS: Molecular genetics and observational case studies of 2 families, each with 1 affected proband with CRD and 3 or 5 unaffected family members. The affected individual from each family received a complete ophthalmic examination including assessment of refractive errors and best-corrected visual acuity, biomicroscopy, color fundus photography, electroretinography analysis, and visual-evoked potential analysis. After complete sequencing of the ABCA4 gene with negative results, the screening for disease-causing mutations was performed by whole-exome sequencing. Possible disease-associated variants were determined by filtering based on minor allele frequency, predicted pathogenicity, and segregation analysis in all family members.

MAIN OUTCOMES AND MEASURES: The appearance of the macula was evaluated by clinical examination, fundus photography, and fundus autofluorescence imaging, and visual function was assessed by electroretinography. Disease-causing mutations were assessed by sequence analyses.

RESULTS: Ophthalmologic findings included markedly reduced visual acuity, bull{\textquoteright}s eye maculopathy, foveal hyperpigmentation, peripapillary atrophy, dyschromatopsia, extinguished photopic responses, and reduced scotopic responses observed on electroretinography consistent with the CRD phenotype often associated with ABCA4 mutations. Although no ABCA4 mutations were detected in either patient, whole-exome sequencing analysis identified 2 new homozygous mutations in the recently described RAB28 gene, the c.172 + 1G>C splice site variant in IVS2 and the missense c.T651G:p.C217W substitution. Both variants were determined as deleterious by predictive programs and were segregated with the disease in both families. Sequencing of 107 additional patients of Spanish descent with CRD did not reveal other cases with RAB28 mutations.

CONCLUSIONS AND RELEVANCE: Deleterious mutations in RAB28 result in a classic CRD phenotype and are an infrequent cause of CRD in the Spanish population.

}, keywords = {Adolescent, Adult, Child, Diagnosis, Differential, DNA Mutational Analysis, Female, Follow-Up Studies, Genetic Predisposition to Disease, Hispanic Americans, Humans, Male, Microscopy, Acoustic, Mutation, Pedigree, Phenotype, rab GTP-Binding Proteins, Retinitis Pigmentosa, Retrospective Studies, Young Adult}, issn = {2168-6173}, doi = {10.1001/jamaophthalmol.2014.4266}, author = {Riveiro-{\'A}lvarez, Rosa and Xie, Yajing Angela and L{\'o}pez-Mart{\'\i}nez, Miguel-{\'A}ngel and Gambin, Tomasz and P{\'e}rez-Carro, Raquel and {\'A}vila-Fern{\'a}ndez, Almudena and L{\'o}pez-Molina, Mar{\'\i}a-Isabel and Zernant, Jana and Jhangiani, Shalini and Muzny, Donna and Yuan, Bo and Boerwinkle, Eric and Gibbs, Richard and Lupski, James R and Ayuso, Carmen and Allikmets, Rando} } @article {120, title = {Nonrecurrent 17p11.2p12 Rearrangement Events that Result in Two Concomitant Genomic Disorders: The PMP22-RAI1 Contiguous Gene Duplication Syndrome.}, journal = {Am J Hum Genet}, volume = {97}, year = {2015}, month = {2015 Nov 05}, pages = {691-707}, abstract = {

The genomic duplication associated with Potocki-Lupski syndrome (PTLS) maps in close proximity to the duplication associated with Charcot-Marie-Tooth disease type 1A (CMT1A). PTLS is characterized by hypotonia, failure to thrive, reduced body weight, intellectual disability, and autistic features. CMT1A is a common autosomal dominant distal symmetric peripheral polyneuropathy. The key dosage-sensitive genes RAI1 and PMP22 are respectively associated with PTLS and CMT1A. Recurrent duplications accounting for the majority of subjects with these conditions are mediated by nonallelic homologous recombination between distinct low-copy repeat (LCR) substrates. The LCRs flanking a contiguous genomic interval encompassing both RAI1 and PMP22 do not share extensive homology; thus, duplications encompassing both loci are rare and potentially generated by a different mutational mechanism. We characterized genomic rearrangements that simultaneously duplicate PMP22 and RAI1, including nine potential complex genomic rearrangements, in 23 subjects by high-resolution array comparative genomic hybridization and breakpoint junction sequencing. Insertions and microhomologies were found at the breakpoint junctions, suggesting potential replicative mechanisms for rearrangement formation. At the breakpoint junctions of these nonrecurrent rearrangements, enrichment of repetitive DNA sequences was observed, indicating that they might predispose to genomic instability and rearrangement. Clinical evaluation revealed blended PTLS and CMT1A phenotypes with a potential earlier onset of neuropathy. Moreover, additional clinical findings might be observed due to the extra duplicated material included in the rearrangements. Our genomic analysis suggests replicative mechanisms as a predominant mechanism underlying PMP22-RAI1 contiguous gene duplications and provides further evidence supporting the role of complex genomic architecture in genomic instability.

}, keywords = {Abnormalities, Multiple, Charcot-Marie-Tooth Disease, Child, Child, Preschool, Chromosome Disorders, Chromosome Duplication, Chromosomes, Human, Pair 17, Comparative Genomic Hybridization, Female, Follow-Up Studies, Gene Duplication, Gene Rearrangement, Genome, Human, Genomics, Humans, Infant, Male, Models, Genetic, Myelin Proteins, Phenotype, Prognosis, Recombination, Genetic, Transcription Factors}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2015.10.003}, author = {Yuan, Bo and Harel, Tamar and Gu, Shen and Liu, Pengfei and Burglen, Lydie and Chantot-Bastaraud, Sandra and Gelowani, Violet and Beck, Christine R and Carvalho, Claudia M B and Cheung, Sau Wai and Coe, Andrew and Malan, Val{\'e}rie and Munnich, Arnold and Magoulas, Pilar L and Potocki, Lorraine and Lupski, James R} }