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Phenotypic and molecular assessment of seven patients with 6p25 deletion syndrome: relevance to ocular dysgenesis and hearing impairment.

Gould DB, Jaafar MS, Addison MK, Munier F, Ritch R, MacDonald IM, Walter MA - BMC Med. Genet. (2004)

Bottom Line: Thirty-nine patients have been described with deletions involving chromosome 6p25.However, relatively few of these deletions have had molecular characterization.Molecular characterization of deletions can identify genes that are responsible for these phenotypes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Ophthalmology, University of Alberta, Edmonton, Alberta, Canada. dbg@jax.org

ABSTRACT

Background: Thirty-nine patients have been described with deletions involving chromosome 6p25. However, relatively few of these deletions have had molecular characterization. Common phenotypes of 6p25 deletion syndrome patients include hydrocephalus, hearing loss, and ocular, craniofacial, skeletal, cardiac, and renal malformations. Molecular characterization of deletions can identify genes that are responsible for these phenotypes.

Methods: We report the clinical phenotype of seven patients with terminal deletions of chromosome 6p25 and compare them to previously reported patients. Molecular characterization of the deletions was performed using polymorphic marker analysis to determine the extents of the deletions in these seven 6p25 deletion syndrome patients.

Results: Our results, and previous data, show that ocular dysgenesis and hearing impairment are the two most highly penetrant phenotypes of the 6p25 deletion syndrome. While deletion of the forkhead box C1 gene (FOXC1) probably underlies the ocular dysgenesis, no gene in this region is known to be involved in hearing impairment.

Conclusions: Ocular dysgenesis and hearing impairment are the two most common phenotypes of 6p25 deletion syndrome. We conclude that a locus for dominant hearing loss is present at 6p25 and that this locus is restricted to a region distal to D6S1617. Molecular characterization of more 6p25 deletion patients will aid in refinement of this locus and the identification of a gene involved in dominant hearing loss.

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Related in: MedlinePlus

Schematic of extent of deletions for 12 patients in the literature with deletions characterized at a molecular level. The black boxes indicate regions where the patients are not deleted. White boxes indicate the minimum extent of the deletion. Grey boxes indicate markers that may or may not be deleted. Genes in this region are listed in bold print. The genetic distance of markers, in Mb (megabases) from the telomere, are also indicated. The source of the information is as follows: Patient A [19], Patient B [28], Patient C is case 2 from [25] and CA from 1, Patients D-G [18], Patient H [10] and SG from [1], Patient I is case 1 from [25] and BD from [1], Patient J is HH from [1], Patient K is JW from [1], Patient L is case 2 from [5].
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Figure 2: Schematic of extent of deletions for 12 patients in the literature with deletions characterized at a molecular level. The black boxes indicate regions where the patients are not deleted. White boxes indicate the minimum extent of the deletion. Grey boxes indicate markers that may or may not be deleted. Genes in this region are listed in bold print. The genetic distance of markers, in Mb (megabases) from the telomere, are also indicated. The source of the information is as follows: Patient A [19], Patient B [28], Patient C is case 2 from [25] and CA from 1, Patients D-G [18], Patient H [10] and SG from [1], Patient I is case 1 from [25] and BD from [1], Patient J is HH from [1], Patient K is JW from [1], Patient L is case 2 from [5].


Phenotypic and molecular assessment of seven patients with 6p25 deletion syndrome: relevance to ocular dysgenesis and hearing impairment.

Gould DB, Jaafar MS, Addison MK, Munier F, Ritch R, MacDonald IM, Walter MA - BMC Med. Genet. (2004)

Schematic of extent of deletions for 12 patients in the literature with deletions characterized at a molecular level. The black boxes indicate regions where the patients are not deleted. White boxes indicate the minimum extent of the deletion. Grey boxes indicate markers that may or may not be deleted. Genes in this region are listed in bold print. The genetic distance of markers, in Mb (megabases) from the telomere, are also indicated. The source of the information is as follows: Patient A [19], Patient B [28], Patient C is case 2 from [25] and CA from 1, Patients D-G [18], Patient H [10] and SG from [1], Patient I is case 1 from [25] and BD from [1], Patient J is HH from [1], Patient K is JW from [1], Patient L is case 2 from [5].
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC455682&req=5

Figure 2: Schematic of extent of deletions for 12 patients in the literature with deletions characterized at a molecular level. The black boxes indicate regions where the patients are not deleted. White boxes indicate the minimum extent of the deletion. Grey boxes indicate markers that may or may not be deleted. Genes in this region are listed in bold print. The genetic distance of markers, in Mb (megabases) from the telomere, are also indicated. The source of the information is as follows: Patient A [19], Patient B [28], Patient C is case 2 from [25] and CA from 1, Patients D-G [18], Patient H [10] and SG from [1], Patient I is case 1 from [25] and BD from [1], Patient J is HH from [1], Patient K is JW from [1], Patient L is case 2 from [5].
Bottom Line: Thirty-nine patients have been described with deletions involving chromosome 6p25.However, relatively few of these deletions have had molecular characterization.Molecular characterization of deletions can identify genes that are responsible for these phenotypes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Ophthalmology, University of Alberta, Edmonton, Alberta, Canada. dbg@jax.org

ABSTRACT

Background: Thirty-nine patients have been described with deletions involving chromosome 6p25. However, relatively few of these deletions have had molecular characterization. Common phenotypes of 6p25 deletion syndrome patients include hydrocephalus, hearing loss, and ocular, craniofacial, skeletal, cardiac, and renal malformations. Molecular characterization of deletions can identify genes that are responsible for these phenotypes.

Methods: We report the clinical phenotype of seven patients with terminal deletions of chromosome 6p25 and compare them to previously reported patients. Molecular characterization of the deletions was performed using polymorphic marker analysis to determine the extents of the deletions in these seven 6p25 deletion syndrome patients.

Results: Our results, and previous data, show that ocular dysgenesis and hearing impairment are the two most highly penetrant phenotypes of the 6p25 deletion syndrome. While deletion of the forkhead box C1 gene (FOXC1) probably underlies the ocular dysgenesis, no gene in this region is known to be involved in hearing impairment.

Conclusions: Ocular dysgenesis and hearing impairment are the two most common phenotypes of 6p25 deletion syndrome. We conclude that a locus for dominant hearing loss is present at 6p25 and that this locus is restricted to a region distal to D6S1617. Molecular characterization of more 6p25 deletion patients will aid in refinement of this locus and the identification of a gene involved in dominant hearing loss.

Show MeSH
Related in: MedlinePlus