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A Novel C-Terminal CIB2 (Calcium and Integrin Binding Protein 2) Mutation Associated with Non-Syndromic Hearing Loss in a Hispanic Family.

Patel K, Giese AP, Grossheim JM, Hegde RS, Hegde RS, Delio M, Samanich J, Riazuddin S, Frolenkov GI, Cai J, Ahmed ZM, Morrow BE - PLoS ONE (2015)

Bottom Line: The carboxy-termini of CIB proteins are associated with calcium binding and intracellular signaling.Our ex vivo studies revealed that the mutation did not alter the interactions of CIB2 with Whirlin, nor its targeting to the tips of hair cell stereocilia.However, we found that the mutation disrupts inhibition of ATP-induced Ca2+ responses by CIB2 in a heterologous expression system.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Avenue, Bronx, New York, United States of America.

ABSTRACT
Hearing loss is a complex disorder caused by both genetic and environmental factors. Previously, mutations in CIB2 have been identified as a common cause of genetic hearing loss in Pakistani and Turkish populations. Here we report a novel (c.556C>T; p.(Arg186Trp)) transition mutation in the CIB2 gene identified through whole exome sequencing (WES) in a Caribbean Hispanic family with non-syndromic hearing loss. CIB2 belongs to the family of calcium-and integrin-binding (CIB) proteins. The carboxy-termini of CIB proteins are associated with calcium binding and intracellular signaling. The p.(Arg186Trp) mutation is localized within predicted type II PDZ binding ligand at the carboxy terminus. Our ex vivo studies revealed that the mutation did not alter the interactions of CIB2 with Whirlin, nor its targeting to the tips of hair cell stereocilia. However, we found that the mutation disrupts inhibition of ATP-induced Ca2+ responses by CIB2 in a heterologous expression system. Our findings support p.(Arg186Trp) mutation as a cause for hearing loss in this Hispanic family. In addition, it further highlights the necessity of the calcium binding property of CIB2 for normal hearing.

No MeSH data available.


Related in: MedlinePlus

Restriction enzyme digestion to validate the CIB2 mutation.Lanes 2 and 3 on the agarose gel represent the restriction digest of a PCR product that was performed on both affected children. The presence of the c.556C>T mutation abolishes the restriction site and results in a single product of 206bp (Lanes 2 and 3, depict the proband and sibling, respectively). Lanes 4 and 5 contain both parental samples and as a result the there is a PCR product of 206bp representing the mutant allele as well as two additional digested fragments at 124bp and 82bp, which represent the normal allele. Lanes 6 and 7 are restriction enzyme digests from two normal, unrelated individuals, with no PCR product corresponding to the mutant allele of 206bp and only two digested PCR products corresponding to the normal allele. Lane 1 contains the DNA size standard ladder.
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pone.0133082.g003: Restriction enzyme digestion to validate the CIB2 mutation.Lanes 2 and 3 on the agarose gel represent the restriction digest of a PCR product that was performed on both affected children. The presence of the c.556C>T mutation abolishes the restriction site and results in a single product of 206bp (Lanes 2 and 3, depict the proband and sibling, respectively). Lanes 4 and 5 contain both parental samples and as a result the there is a PCR product of 206bp representing the mutant allele as well as two additional digested fragments at 124bp and 82bp, which represent the normal allele. Lanes 6 and 7 are restriction enzyme digests from two normal, unrelated individuals, with no PCR product corresponding to the mutant allele of 206bp and only two digested PCR products corresponding to the normal allele. Lane 1 contains the DNA size standard ladder.

Mentions: Through this initial search, we identified a homozygous mutation in CIB2 (c.556C>T; p.(Arg186Trp)) in both affected siblings, whereas the healthy parents are unaffected carriers (Fig 2). The c.556C>T (p.Arg186Trp) mutation is located in exon 6 of CIB2, which encodes the carboxy-terminal end of the resulting polypeptide. The mutation in the female proband found by WES was validated by Sanger sequence analysis (Fig 2A). This nucleotide change was not observed in the normal population (1000 Genomes Project; NHLBI ESP6500). We performed a mutation specific restriction enzyme digest (Fig 3) in 94 ethnically matched (Hispanic) and a 100 African American unrelated healthy individuals and did not identify the mutation in any of the subjects, suggesting this mutation is truly rare in both populations (data not shown). This nucleotide change has been observed as a rare heterozygous variant in an African American control samples and was absent in a further 8586 European controls samples studied, as part of the NHLBI Exome Sequencing Project (ESP; S1 Table).


A Novel C-Terminal CIB2 (Calcium and Integrin Binding Protein 2) Mutation Associated with Non-Syndromic Hearing Loss in a Hispanic Family.

Patel K, Giese AP, Grossheim JM, Hegde RS, Hegde RS, Delio M, Samanich J, Riazuddin S, Frolenkov GI, Cai J, Ahmed ZM, Morrow BE - PLoS ONE (2015)

Restriction enzyme digestion to validate the CIB2 mutation.Lanes 2 and 3 on the agarose gel represent the restriction digest of a PCR product that was performed on both affected children. The presence of the c.556C>T mutation abolishes the restriction site and results in a single product of 206bp (Lanes 2 and 3, depict the proband and sibling, respectively). Lanes 4 and 5 contain both parental samples and as a result the there is a PCR product of 206bp representing the mutant allele as well as two additional digested fragments at 124bp and 82bp, which represent the normal allele. Lanes 6 and 7 are restriction enzyme digests from two normal, unrelated individuals, with no PCR product corresponding to the mutant allele of 206bp and only two digested PCR products corresponding to the normal allele. Lane 1 contains the DNA size standard ladder.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591343&req=5

pone.0133082.g003: Restriction enzyme digestion to validate the CIB2 mutation.Lanes 2 and 3 on the agarose gel represent the restriction digest of a PCR product that was performed on both affected children. The presence of the c.556C>T mutation abolishes the restriction site and results in a single product of 206bp (Lanes 2 and 3, depict the proband and sibling, respectively). Lanes 4 and 5 contain both parental samples and as a result the there is a PCR product of 206bp representing the mutant allele as well as two additional digested fragments at 124bp and 82bp, which represent the normal allele. Lanes 6 and 7 are restriction enzyme digests from two normal, unrelated individuals, with no PCR product corresponding to the mutant allele of 206bp and only two digested PCR products corresponding to the normal allele. Lane 1 contains the DNA size standard ladder.
Mentions: Through this initial search, we identified a homozygous mutation in CIB2 (c.556C>T; p.(Arg186Trp)) in both affected siblings, whereas the healthy parents are unaffected carriers (Fig 2). The c.556C>T (p.Arg186Trp) mutation is located in exon 6 of CIB2, which encodes the carboxy-terminal end of the resulting polypeptide. The mutation in the female proband found by WES was validated by Sanger sequence analysis (Fig 2A). This nucleotide change was not observed in the normal population (1000 Genomes Project; NHLBI ESP6500). We performed a mutation specific restriction enzyme digest (Fig 3) in 94 ethnically matched (Hispanic) and a 100 African American unrelated healthy individuals and did not identify the mutation in any of the subjects, suggesting this mutation is truly rare in both populations (data not shown). This nucleotide change has been observed as a rare heterozygous variant in an African American control samples and was absent in a further 8586 European controls samples studied, as part of the NHLBI Exome Sequencing Project (ESP; S1 Table).

Bottom Line: The carboxy-termini of CIB proteins are associated with calcium binding and intracellular signaling.Our ex vivo studies revealed that the mutation did not alter the interactions of CIB2 with Whirlin, nor its targeting to the tips of hair cell stereocilia.However, we found that the mutation disrupts inhibition of ATP-induced Ca2+ responses by CIB2 in a heterologous expression system.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Avenue, Bronx, New York, United States of America.

ABSTRACT
Hearing loss is a complex disorder caused by both genetic and environmental factors. Previously, mutations in CIB2 have been identified as a common cause of genetic hearing loss in Pakistani and Turkish populations. Here we report a novel (c.556C>T; p.(Arg186Trp)) transition mutation in the CIB2 gene identified through whole exome sequencing (WES) in a Caribbean Hispanic family with non-syndromic hearing loss. CIB2 belongs to the family of calcium-and integrin-binding (CIB) proteins. The carboxy-termini of CIB proteins are associated with calcium binding and intracellular signaling. The p.(Arg186Trp) mutation is localized within predicted type II PDZ binding ligand at the carboxy terminus. Our ex vivo studies revealed that the mutation did not alter the interactions of CIB2 with Whirlin, nor its targeting to the tips of hair cell stereocilia. However, we found that the mutation disrupts inhibition of ATP-induced Ca2+ responses by CIB2 in a heterologous expression system. Our findings support p.(Arg186Trp) mutation as a cause for hearing loss in this Hispanic family. In addition, it further highlights the necessity of the calcium binding property of CIB2 for normal hearing.

No MeSH data available.


Related in: MedlinePlus