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Challenges and solutions for gene identification in the presence of familial locus heterogeneity
Journal article   Open access   Peer reviewed

Challenges and solutions for gene identification in the presence of familial locus heterogeneity

Atteeq U Rehman, Regie Lyn P Santos-Cortez, Meghan C Drummond, Mohsin Shahzad, Kwanghyuk Lee, Robert J Morell, Muhammad Ansar, Abid Jan, Xin Wang, Abdul Aziz, …
European journal of human genetics : EJHG, Vol.23(9), pp.1207-1215
09/2015
DOI: 10.1038/ejhg.2014.266
PMCID: PMC4538203
PMID: 25491636
url
https://doi.org/10.1038/ejhg.2014.266View
Published (Version of record) Open Access

Abstract

Next-generation sequencing (NGS) of exomes and genomes has accelerated the identification of genes involved in Mendelian phenotypes. However, many NGS studies fall short of identifying causal variants, with estimates for success rates as low as 25% for uncovering the pathological variant underlying disease etiology. An important reason for such failures is familial locus heterogeneity, where within a single pedigree causal variants in two or more genes underlie Mendelian trait etiology. As examples of intra- and inter-sibship familial locus heterogeneity, we present 10 consanguineous Pakistani families segregating hearing impairment due to homozygous variants in two different hearing impairment genes and a European-American pedigree in which hearing impairment is caused by four variants in three different genes. We have identified 41 additional pedigrees with syndromic and nonsyndromic hearing impairment for which a single previously reported hearing impairment gene has been identified but only segregates with the phenotype in a subset of affected pedigree members. We estimate that locus heterogeneity occurs in 15.3% (95% confidence interval: 11.9%, 19.9%) of the families in our collection. We demonstrate novel approaches to apply linkage analysis and homozygosity mapping (for autosomal recessive consanguineous pedigrees), which can be used to detect locus heterogeneity using either NGS or SNP array data. Results from linkage analysis and homozygosity mapping can also be used to group sibships or individuals most likely to be segregating the same causal variants and thereby increase the success rate of gene identification.
Mutation Phenotype Hearing Loss - diagnosis Humans Male Genetic Loci Sulfate Transporters Membrane Transport Proteins - genetics Hepatocyte Growth Factor - genetics Female Genetic Linkage Genetic Predisposition to Disease Hearing Loss - ethnology Connexins - genetics European Continental Ancestry Group Genotype Chromosome Mapping Hearing Loss - pathology Genes, Recessive Genetic Heterogeneity Connexin 26 Hearing Loss - genetics Homozygote Asian Continental Ancestry Group Pedigree Consanguinity High-Throughput Nucleotide Sequencing Genome, Human Calcium-Binding Proteins - genetics

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