PROMM and deafness: exclusion of ZNF9 as the disease gene in DFNA18 suggests a polygenic origin of the PROMM/DM2 phenotype

[A new gene locus for an autosomal-dominant non-syndromic hearing impairment (DFNA 33) is situated on chromosome 13q34-qter]

By investigation of a German family pedigree with non-syndromic hearing impairment of early onset and autosomal-dominant mode of inheritance, linkage to known DFNA loci was excluded, and the existence of a new locus (DFNA33) was revealed. In a subsequent genomic scan the phenotype was mapped to a 6 cM interval on chromosome 13q34-qter. A maximum two-point lod score of 2.96 was obtained for the marker D13S285 with a maximum lod score in the multipoint analysis of 3.28 at 124.56 cM.

[A new locus for an autosomal dominant, non-syndromic hearing impairment (DFNA57) located on chromosome 19p13.2 and overlapping with DFNB15]

BACKGROUND

Non-syndromic hearing loss is the most genetically heterogeneous trait known in humans. To date, 54 loci for autosomal dominant non-syndromic sensorineural hearing loss (NSSHL) have been identified by linkage analysis.

METHODS

In this study a German pedigree has been identified segregating a progressive bilateral loss of lower and middle frequencies.

RESULTS

A genome-wide screening and linkage analysis revealed the existence of a new NSSHL locus (DFNA57). The phenotype was mapped to a 10 degrees Mbp interval on chromosome 19p13.2 from 7.8 to 18.2 degrees Mbp, a maximum 2-point LOD score of 3.08 was obtained for the marker D19S586. The region overlaps with the recessive locus DFNB15.

CONCLUSION

The results underline the heterogeneity of hereditary hearing disorders. Identification of genes can help to reach a better understanding of the molecular mechanism of hearing.

A novel autosomal recessive nonsyndromic hearing impairment locus (DFNB42) maps to chromosome 3q13.31-q22.3

A consanguineous family with autosomal recessive nonsyndromic hearing impairment (NSHI) was ascertained in Pakistan and displayed significant evidence of linkage to 3q13.31-q22.3. The novel locus (DFNB42) segregating in this kindred, maps to a 21.6 cM region according to a genetic map constructed using data from both the deCode and Marshfield genetic maps. This region of homozygosity is flanked by markers D3S1278 and D3S2453. A maximum multipoint LOD score of 3.72 was obtained at marker D3S4523. DFNB42 represents the third autosomal recessive NSHI locus to map to chromosome 3.