A novel splice-acceptor site mutation in CDH3 gene in a consanguineous family exhibiting hypotrichosis with juvenile macular dystrophy

Mutations in CDH3 gene, encoding P-cadherin, are responsible for hypotrichosis with juvenile macular dystrophy (HJMD), which is a rare autosomal recessive disorder. The HJMD is characterized by congenital sparse hair on scalp and progressive severe degenerative changes of the retinal macula which leads to variable degrees of blindness. The present study reports a large consanguineous Pakistani family with six individuals affected with HJMD. Genotyping using polymorphic microsatellite markers showed linkage of the family to CDH3 gene on chromosome 16q22.1. Sequence analysis of the CDH3 gene revealed a novel splice site mutation (c.IVS10-1 G → A) in intron 10, which leads to skipping of exon 11 and probably synthesizing a non-functional premature truncated protein.

A novel splice site mutation in the EDAR gene underlies autosomal recessive hypohidrotic ectodermal dysplasia in a Pakistani family

Hypohidrotic ectodermal dysplasia is a rare congenital disorder that results in abnormalities in the structures of ectodermal origin: hair, teeth, and eccrine sweat glands. DNA sequence analysis of EDAR gene in a Pakistani family, demonstrating autosomal recessive form of hypohidrotic ectodermal dysplasia, identified a novel homozygous mutation affecting splice donor site of exon 5 [IVS5+1G > or = C] of the gene.

Noncoding mutations of HGF are associated with nonsyndromic hearing loss, DFNB39

A gene causing autosomal-recessive, nonsyndromic hearing loss, DFNB39, was previously mapped to an 18 Mb interval on chromosome 7q11.22-q21.12. We mapped an additional 40 consanguineous families segregating nonsyndromic hearing loss to the DFNB39 locus and refined the obligate interval to 1.2 Mb. The coding regions of all genes in this interval were sequenced, and no missense, nonsense, or frameshift mutations were found. We sequenced the noncoding sequences of genes, as well as noncoding genes, and found three mutations clustered in intron 4 and exon 5 in the hepatocyte growth factor gene (HGF). Two intron 4 deletions occur in a highly conserved sequence that is part of the 3' untranslated region of a previously undescribed short isoform of HGF. The third mutation is a silent substitution, and we demonstrate that it affects splicing in vitro. HGF is involved in a wide variety of signaling pathways in many different tissues, yet these putative regulatory mutations cause a surprisingly specific phenotype, which is nonsydromic hearing loss. Two mouse models of Hgf dysregulation, one in which an Hgf transgene is ubiquitously overexpressed and the other a conditional knockout that deletes Hgf from a limited number of tissues, including the cochlea, result in deafness. Overexpression of HGF is associated with progressive degeneration of outer hair cells in the cochlea, whereas cochlear deletion of Hgf is associated with more general dysplasia.

Mutations in the P2RY5 gene underlie autosomal recessive hypotrichosis in 13 Pakistani families

BACKGROUND

Autosomal recessive hypotrichosis is a rare genetic irreversible hair loss characterized by sparse scalp hair, sparse to absent eyebrows and eyelashes, and sparse axillary and body hair. Affected male individuals have normal beard hair.

OBJECTIVES

To search for pathogenic mutations in the human P2RY5 gene in Pakistani families with autosomal recessive hereditary hypotrichosis.

METHODS

In the present report, 16 unrelated consanguineous Pakistani families having multiple affected individuals with autosomal recessive hypotrichosis were investigated. Linkage in these families was searched by genotyping microsatellite markers linked to autosomal recessive hypotrichosis loci LAH1, LAH2 and LAH3. Thirteen of the families showed linkage to the LAH3 locus on chromosome 13q14.11-q21.32. These families were then subjected to direct sequencing of the P2RY5 gene, which encodes a G protein-coupled receptor.

RESULTS

Sequence analysis of the P2RY5 gene revealed two novel missense mutations (c.742A>T; p.N248Y and c.830C>T; p.L277P) in three families. Five previously described mutations including three missense (c.188A>T; p.D63V, c.436G>A; p.G146R, c.562A>T; p.I188F), one insertion (c.69insCATG; p.24insHfsX52) and one complex deletion (c.172-175delAACT; 177delG; p.N58-L59delinsCfsX88) were detected in the other 10 families.

CONCLUSIONS

Mutations revealed in the present study extend the body of evidence implicating the P2RY5 gene in the pathogenesis of human hereditary hair loss.

A novel insertion mutation in the cartilage-derived morphogenetic protein-1 (CDMP1) gene underlies Grebe-type chondrodysplasia in a consanguineous Pakistani family

Background

Grebe-type chondrodysplasia (GCD) is a rare autosomal recessive syndrome characterized by severe acromesomelic limb shortness with non-functional knob like fingers resembling toes. Mutations in the cartilage-derived morphogenetic protein 1 (CDMP1) gene cause Grebe-type chondrodysplasia.

Methods

Genotyping of six members of a Pakistani family with Grebe-type chondrodysplasia, including two affected and four unaffected individuals, was carried out by using polymorphic microsatellite markers, which are closely linked to CDMP1 locus on chromosome 20q11.22. To screen for a mutation in CDMP1 gene, all of its coding exons and splice junction sites were PCR amplified from genomic DNA of affected and unaffected individuals of the family and sequenced directly in an ABI Prism 310 automated DNA sequencer.

Results

Genotyping results showed linkage of the family to CDMP1 locus. Sequence analysis of the CDMP1 gene identified a novel four bases insertion mutation (1114insGAGT) in exon 2 of the gene causing frameshift and premature termination of the polypeptide.

Conclusion

We describe a 4 bp novel insertion mutation in CDMP1 gene in a Pakistani family with Grebe-type chondrodysplasia. Our findings extend the body of evidence that supports the importance of CDMP1 in the development of limbs.

Mutation in the HPGD gene encoding NAD+ dependent 15-hydroxyprostaglandin dehydrogenase underlies isolated congenital nail clubbing (ICNC)

BACKGROUND

Isolated congenital nail clubbing (ICNC) is a rare autosomal recessive disorder characterised by enlargement of the terminal segments of fingers and toes with thickened nails due to proliferation of the connective tissues and abnormal function of the nail matrix. In the present study, we investigated a large Pakistani family with 11 affected individuals having hereditary congenital nail clubbing as a single invariable clinical feature without any associated ectodermal, skeletal or systemic imperfection.

OBJECTIVE

To identify a gene underlying the ICNC phenotype.

METHODS

A genome wide homozygosity linkage mapping strategy was used to identify the gene causing ICNC. DNA sequencing was performed to screen 10 candidate genes located in the linkage interval.

RESULTS

We assigned the disease locus for the ICNC to a 13.25 cM region on chromosome 4q32.3-q34.1. This region corresponds to 12.27 Mbp according to the sequence based physical map (Build 36.1) and flanked by markers D4S2952 and D4S415. A maximum two point LOD score of 2.98 ( theta= 0.00) was obtained at marker D4S2368 while a maximum multipoint LOD score of 3.62 was obtained with several markers along the disease interval. Sequence analysis of the candidate genes, in the ICNC linkage interval, revealed a homozygous missense mutation (c.577T>C; p.S193P) in exon 6 of the human HPGD gene encoding NAD(+) dependent 15-hydroxyprostaglandin dehydrogenase (15-PGDH).

CONCLUSIONS

The involvement of 15-PGDH in the pathogenesis of ICNC may open up interesting perspectives into the function of this enzyme in nail morphogenesis/development.

Novel mutations in G protein-coupled receptor gene (P2RY5) in families with autosomal recessive hypotrichosis (LAH3)

Autosomal recessive hypotrichosis (LAH3) is a rare hair disorder characterized by sparse hair on scalp and the rest of the body of affected individuals. Recently mutations in a G protein-coupled receptor gene, P2RY5, located at LAH3 locus, have been reported in several families with autosomal recessive hypotrichosis simplex and woolly hair. For the present study, 22 Pakistani families with autosomal recessive hypotrichosis were enrolled. Genotyping using microsatellite markers linked to three autosomal recessive forms of hypotrichosis (LAH1, LAH2, LAH3) showed the linkage of 2 families to the LAH2 locus and 14 to the LAH3 locus. The remaining 6 families were not linked to any of the three loci. Families linked to LAH3 locus were further subjected to screening of the P2RY5 gene with direct DNA sequencing. Three previously reported variants, c.69insCATG (p.24insHfs52), c.188A > T (p.D63V) and c.565G > A (p.E189K) were observed in eight families. Four novel nonsynonymous sequence variants, c.8G > C (p.S3T), c.36insA (p.D13RfsX16), c.160insA (p.N54TfsX58) and c.436G > A (p.G146R) were found to segregate within six families.

A novel deletion mutation in LIPH gene causes autosomal recessive hypotrichosis (LAH2)

Autosomal recessive hypotrichosis is a rare hereditary disorder characterized by sparse hair on scalp and rest of the body of affected subjects. Recently, three clinically similar autosomal recessive forms of hypotrichosis [localized autosomal recessive hypotrichosis (LAH)1], LAH2 and LAH3 have been mapped on chromosomes 18q12.1, 3q27.3, and 13q14.11-q21.32, respectively. For these three loci, two genes DSG4 for LAH1 and LIPH for LAH2 have been identified. To date, only five mutations in DSG4 and two in LIPH genes have been reported. In this study, we have ascertained two large unrelated consanguineous Pakistani families with autosomal recessive form of hypotrichosis. Affected individuals showed homozygosity to the microsatellite markers tightly linked to LIPH gene on chromosome 3q27. Sequence analysis of the gene in the affected subjects from both the families revealed a novel deletion mutation in exon 5 (c.659-660delTA) causing frameshift and downstream premature termination codon. All the three mutations identified in the LIPH gene, including the one in this study, are deletion mutations.

Intragenic deletions in the dystrophin gene in 211 Pakistani Duchenne muscular dystrophy patients

BACKGROUND

Deletions of single or multiple exonic regions within the dystrophin gene can be detected using current molecular methods in approximately 65% of the patients with X-linked recessive neuromuscular disorder, Duchenne/Becker muscular dystrophy (DMD/BMD). Population-based variations in frequency and distribution of dystrophin gene deletions have been reported in DMD/BMD patients. In the present study, the first in the Pakistani population, frequency and distribution of deletions of 18 exons clustered in two hot spots within the dystrophin gene in 211 unrelated DMD patients were analyzed.

METHODS

A total of 211 patients suffering from DMD were ascertained, and intragenic deletions within the dystrophin gene were detected on polymerase chain reaction amplification of the genomic DNA using 18 primer sets clustered within two major deletion hot spots. lovd v.1.1.0 software from the Leiden Muscular Dystrophy website has been used to predict in-frame and out-of-frame deletions.

RESULTS

Intragenic deletions were detected in 86 patients (40.75%): 35 patients (40.69%) had deletions within the proximal hot spot, and 51 patients (59.30%) had deletions confined to the distal deletion hot spot of the dystrophin gene. The most frequently deleted exons were 50, 6, 47, 13 and 52 with deletion frequencies of 15.11%, 12.79%, 10.46%, 8.13%, and 4.65%, respectively. lovd v.1.1.0 predicted out-of-frame deletions in 67 DMD patients and in-frame deletions in 19 DMD patients.

CONCLUSIONS

The observed proportion of intragenic deletions in the Pakistani population is relatively low, which is comparable with most of the Asian data. Also, deletions in 67 patients (77.9%) are in agreement with the frame-shift rule.

Novel protein-truncating mutations in the ASPM gene in families with autosomal recessive primary microcephaly

Autosomal recessive primary microcephaly (MCPH) is a neurodevelopmental disorder that causes reduction in brain size. Individuals affected with the disorder show a small but architecturally normal cerebral cortex and are associated with mental retardation of mild-to severe form. MCPH is genetically heterogeneous with six loci, and four genes have been identified so far. Homozygous mutations in the ASPM gene, located at MCPH5 locus on chromosome 1q31, are the most common cause of MCPH particularly in the Pakistani population. In the present study, we have ascertained ten Pakistani and one Kashmiri family with primary microcephaly. We screened for potential mutations of the ASPM gene in seven consanguineous families (six Pakistani and one Kashmiri) linked to MCPH5 locus. Two previously reported (8508delGA, W1326X) and four novel sequence variants (Y1712X, I1717X, Y3353X, R3244X) were detected and all were predicted to be protein truncating. The degree of mental retardation in the affected individuals of the seven families varied from mild to moderate, and was not dependent on the location of mutations in the ASPM gene.

A novel locus for ectodermal dysplasia of hairs, nails and teeth type maps to chromosome 18q22.1-22.3

Ectodermal dysplasias (EDs) are developmental disorders affecting tissues of ectodermal origin including hair, nails, teeth and sweat glands. Ectodermal dysplasia of hair, nails and teeth is a rare type of congenital disorder characterized by sparse and thin hair, dystrophic finger-and toenails and missing and abnormal teeth. In an effort to understand the molecular basis of this form of ED a family of Pakistani origin with an autosomal recessive pattern of inheritance was ascertained from a remote region in Pakistan. The clinical features of the affected individuals included thin and fine hair on the scalp, dystrophic and flat nails, absent or sparse eyebrows and eyelashes, missing and abnormal teeth, and thin body hair. A human genome scan carried out using microsatellite markers mapped the disease locus in this family to chromosome 18q22.1-18q22.3. A maximum two-point LOD score of 2.73 (theta= 0.0) was obtained at marker D18S541. Multipoint linkage analysis resulted in a maximum LOD score of 3.42 obtained with several markers, including D18S1125, ATA82B02, D18S848, D18S488, D18S1091, and D18S485, which supported the linkage. The linkage interval is flanked by markers D18S857 and D18S815, which corresponds to a region of 17.32 cM according to Rutgers combined linkage and physical map (build 36). This region covers 8.63 Mb according to the sequence-based physical map. Three candidate genes, CDH7, CDH19 and ZNF407, from the linkage interval were sequenced and found to be negative for functional sequence variants. This study is the first step towards the identification of a gene involved in hair, nails and teeth type ED.

Previously described sequence variant in CDK5RAP2 gene in a Pakistani family with autosomal recessive primary microcephaly

Background

Autosomal Recessive Primary Microcephaly (MCPH) is a disorder of neurogenic mitosis. MCPH leads to reduced cerebral cortical volume and hence, reduced head circumference associated with mental retardation of variable degree. Genetic heterogeneity is well documented in patients with MCPH with six loci known, while pathogenic sequence variants in four respective genes have been identified so far. Mutations in CDK5RAP2 gene at MCPH3 locus have been least involved in causing MCPH phenotype.

Methods

All coding exons and exon/intron splice junctions of CDK5RAP2 gene were sequenced in affected and normal individuals of Pakistani MCPH family of Kashmiri origin, which showed linkage to MCPH3 locus on chromosome 9q33.2.

Results

A previously described nonsense mutation [243 T>A (S81X)] in exon 4 of CDK5RAP2 gene has been identified in the Pakistani family, presented here, with MCPH Phenotype. Genomic and cDNA sequence comparison revealed that the exact nomenclature for this mutation is 246 T>A (Y82X).

Conclusion

Recurrent observation of Y82X mutation in CDK5RAP2 gene in this Pakistani family may be a sign of confinement of a rare ancestral haplotype carrying this pathogenic variant within Northern Pakistani population, as this has not been reported in any other population.

Localization of a novel autosomal recessive hypotrichosis locus (LAH3) to chromosome 13q14.11-q21.32

Autosomal recessive hypotrichosis is a rare form of alopecia characterized by sparse hair on scalp, sparse to absent eyebrows and eyelashes, and sparse auxiliary and body hair. Previously, for this form of hypotrichosis, two loci LAH (localized hereditary hypotrichosis) and AH (autosomal recessive hereditary hypotrichosis) have been mapped on chromosome 18q12.1 and 3q27.2, respectively. In the study presented here, we report the localization of a third locus for autosomal recessive form of hypotrichosis in two large Pakistani families. The patients in the two families exhibited typical features of the hereditary hypotrichosis. Genome scan using polymorphic microsatellite markers mapped the gene on chromosome 13q14.11-q21.32. A maximum combined two-point logarithm of odds (LOD) score of 4.79 at theta= 0.0 was obtained for several markers. Multipoint linkage analysis resulted in a maximum LOD score of 5.9, which further supports the linkage. Haplotype analysis defined the linkage interval of 17.35 cM flanked by markers D13S325 and D13S1231 according to the Rutgers combined linkage-physical map. This region contains 24.41 Mb according to the build 36 of the human genome sequence-based physical map.

Pure hair-nail ectodermal dysplasia maps to chromosome 12p11.1-q21.1 in a consanguineous Pakistani family

Ectodermal dysplasias (ED) are developmental disorders affecting tissues of ectodermal origin including hair, nail, teeth and sweat glands. To date, four different types of ectodermal dysplasias involving only hair and nails have been described. In an effort to understand the molecular basis of ED of hair and nails, a Pakistani family with multiple affected individuals was studied. Linkage analysis was carried out by genotyping eight members of the family (five normal and three affected) using microsatellite markers linked to the related phenotype. The diseased phenotype was mapped to chromosome 12p11.1-q21.1 (Zmax=3.1). DNA sequence analysis of the coding exons and splice sites of six hair keratin genes, located in the linkage interval, failed to detect any pathogenic mutation in the affected individuals of the family. Failure to detect a mutation in the epithelial keratin genes suggests that the mutation lies either in the regulatory region of one of the keratin genes or in another unknown gene, located in the linkage interval, with a possible role in the development of ectodermal appendages.

Ectodermal dysplasia of hair and nail type: mapping of a novel locus to chromosome 17p12-q21.2

BACKGROUND

Ectodermal dysplasias (EDs) describe a large and complex group of disorders characterized by abnormal development of the skin and appendages (hair, nails, teeth and sweat glands). Of the approximately 200 different EDs, about 30 have been studied at the molecular level. In an effort to understand the molecular bases of ED of hair and nail type, we studied a Pakistani consanguineous family with multiple affected individuals.

OBJECTIVES

To localize the gene responsible for the autosomal recessive form of ED of hair and nail type.

METHODS

Genotyping of nine members of the family, including five affected and four normal individuals was performed using microsatellite markers mapping to candidate regions, harbouring genes involved in related phenotypes. Five epithelial keratin genes located in the candidate region were sequenced to identify the pathogenic mutation.

RESULTS

We mapped the disease locus to a 24.2-cM interval flanked by markers D17S839 and D17S1299 on chromosome 17p12-q21.2 (Z(max) = 4.4). DNA sequencing of five epithelial keratin candidate genes, present in the disease locus, did not reveal any pathogenic mutation in the affected individuals.

CONCLUSIONS

The gene for ED of hair and nail type has been mapped to chromosome 17p12-q21.2 in a Pakistani consanguineous family. Failure to detect mutations in epithelial keratin genes suggests that the mutation may lie either in regulatory regions of one of the epithelial keratin genes or in another unknown gene, located in the linkage interval, with a possible role in the development of ectodermal appendages.

Mapping of a gene for alopecia with mental retardation syndrome (APMR3) on chromosome 18q11.2-q12.2

Alopecia with mental retardation syndrome (APMR) is a rare autosomal recessive disorder characterized by total or partial absence of hair from the scalp and other parts of the body and associated with mental retardation. Previously, we have reported the mapping of two alopecia and mental retardation genes (APMR1 and APMR2) on human chromosome 3. In the present study, after excluding both of these loci through linkage analysis, a whole genome scan was performed by genotyping 396 polymorphic microsatellite markers located on 22 autosomes and the X and Y chromosomes. A disease locus was mapped to a 10.9 cM region, flanked by markers D18S866 and D18S811, on chromosome 18q11.2-q12.2. A maximum two-point LOD score of 3.03 at theta= 0.0 was obtained with marker D18S1102. Multipoint linkage analysis resulted in maximum LOD scores of 4.03 with several markers in the candidate region. According to the Rutgers combined linkage-physical map of the human genome (build 36) this region covers 12.17 Mb. DNA sequence analysis of nine candidate genes including DSC3, DSC1, DSG1, DSG4, DSG3, ZNF397, ZNF271, ZNF24 and ZNF396 did not reveal any sequence variants in the affected individuals of the family presented here.

A mutation in the lipase H (LIPH) gene underlie autosomal recessive hypotrichosis

Hereditary hypotrichosis is a rare autosomal recessive disorder characterized by sparse hair on scalp and rest of the body of affected individuals. Two forms of such hypotrichosis LAH and AH have been mapped on chromosome 18q12.1 and 3q27, respectively. Mutations in desmogelin 4 (DSG4) gene have been reported to underlie LAH. Recently, a deletion mutation in Lipase H (LIPH) gene, located at AH locus, has been identified in two ethnic groups of Russian population. In the present study, a four generation Pakistani family with AH phenotype has been mapped to chromosome 3q27. Sequence analysis of candidate gene LIPH revealed a novel five base pair deletion mutation (c.346-350delATATA) in exon 2 of the gene leading to frameshift and downstream premature termination codon. The mutation reported in the family, presented here, is the second mutation identified in LIPH gene. The identification of a genetic defect in LIPH suggests that this enzyme regulates hair growth.

Prevalence of coronary heart disease in Kashmiris

Coronary Heart Disease (CHD) is one of the major causes of mortality and morbidity in the general population of both the developing and developed countries. Prevalence of CHD in the Indian subcontinent is presently one of the highest and is further on an increase. In the state of Jammu and Kashmir the population like any other developing community, is undergoing lifestyle changes but the unusual stress and strain for the last 15 years of the disturbed situation in the state apparently has contributed to increase the prevalence of CHD. Therefore an epidemiological study was conducted to assess the prevalence of CHD in both rural and urban areas of the valley. This study was carried out in the rural and urban areas of the twin districts of Anantnag and Srinagar by random sampling. The total population of the study area comprised of 44,305 persons out of which the target population was 13,893. The study was carried out on 3128 (23%) subjects (2284 males and 844 females) aged 40 years and above. In rural areas the study was conducted in a cluster of 3 villages in each district on 1552 persons (1088 males and 464 females) and in urban areas it was carried out in 3 mohallas (closed locality) in each district on 1576 persons (1196 males and 380 females). A complete history and clinical examination was done and Rose Questionnaire was recorded for angina. ECG was done in all subjects. Chi square test was used for statistical analysis. The overall prevalence of CHD in the population studied by all diagnostic measures was 7.54%. The overall rural prevalence was 6.70% and urban prevalence was 8.37%. Prevalence of CHD was higher in males, 7.88% and slightly lower in females, 6.63%.

A novel locus for alopecia with mental retardation syndrome (APMR2) maps to chromosome 3q26.2-q26.31

Congenital alopecia may occur either alone or in association with ectodermal and other abnormalities. On the bases of such associations, several different syndromes featuring congenital alopecia can be distinguished. Alopecia with mental retardation syndrome (APMR) is a rare autosomal recessive disorder, clinically characterized by total or partial hair loss and mental retardation. In the present study, a five-generation Pakistani family with multiple affected individuals with APMR was ascertained. Patients in this family exhibited typical features of APMR syndrome. The disease locus was mapped to chromosome 3q26.2-q26.31 by carrying out a genome scan followed by fine mapping. A maximum two-point logarithm of odds (LOD) score of 2.93 at theta=0.0 was obtained at markers D3S3053 and D3S2309. Multipoint linkage analysis resulted in a maximum LOD score of 4.57 with several markers, which supports the linkage. The disease locus was flanked by markers D3S1564 and D3S2427, which corresponds to 9.6-cM region according to the Rutgers combined linkage-physical map of the human genome (build 35) and contains 5.6 Mb. The linkage interval of the APMR locus identified here does not overlap with the one described previously; therefore, this locus has been designated as APMR2.

Telomerase activity and hTERT mRNA expression in glial tumors

Human telomerase is a structurally complex ribonucleoprotein that is responsible for the maintenance of telomeric DNA at the ends of the chromosomes. The enzyme is proposed as having an important role in cell immortalization and oncogenesis. A limited number of studies have been performed on the telomerase system in brain tumors, and these studies are somewhat conflicting. The relative ineffectiveness of current therapies for malignant gliomas led to the need for novel targets for more promising approaches. In order to clarify the prognostic significance of telomerase expression in gliomas and to speculate on therapeutic implications, we examined telomerase activity by the telomeric repeat amplification protocol (TRAP) assay in 42 gliomas, (32 multiform glioblastomas, 4 anaplastic astrocytomas, 4 differentiated astrocytomas, 1 oligoastrocytoma and 1 oligosarcoma). Telomerase messenger expression (hTERT mRNA) was evaluated by reverse transcription-PCR analysis in the same group of tumors. High telomerase activity was detected in 21/42 gliomas (50%). The levels of telomerase in terms of its messenger level expression overlapped the activity; in fact, a significant association between telomerase activity and hTERT mRNA expression was found (chi2 test; p<0.0001). At univariate analysis, advanced age as well as high telomerase activity and hTERT mRNA levels were seen to be significant predictors of worse prognosis regarding both overall survival (p=0.007, p=0.007, p=0.04, respectively) and disease-free interval (p=0.008, p=0.008, p=0.04, respectively). All these variables maintained a significant independent prognostic role in multivariate analysis. Telomerase may represent an indicator of progression and poor prognosis in this type of cancer, with interesting therapeutic implications.

The mapping of DFNB62, a new locus for autosomal recessive non-syndromic hearing impairment, to chromosome 12p13.2-p11.23

Autosomal recessive non-syndromic hearing impairment (ARNSHI) is the most common form of prelingual inherited hearing impairment (HI). Here is described the mapping of a novel ARNSHI locus in a consanguineous Pakistani family with profound congenital HI. Two-point and multipoint linkage analyses were performed for the genome scan and fine mapping markers. Haplotypes were constructed to determine the region of homozygosity. At theta = 0, the maximum two-point LOD score of 4.0 was obtained at marker AAC040. A maximum multipoint LOD score of 5.3 was derived at marker D12S320, with the three-unit support interval demarcated by D12S89 and D12S1042. The region of homozygosity is flanked by markers D12S358 and D12S1042, which corresponds to 22.4 cM according to the Rutgers combined linkage-physical map of the human genome and spans 15.0 Mb on the sequence-based physical map. A novel ARNSHI locus DFNB62 was mapped to chromosome 12p13.2-p11.23. DFNB62 represents the second ARNSHI locus to map to chromosome 12.

DFNB68, a novel autosomal recessive non-syndromic hearing impairment locus at chromosomal region 19p13.2

From a large collection of families with autosomal recessive non-syndromic hearing impairment (NSHI) from Pakistan, linkage has been established for two unrelated consanguineous families to 19p13.2. This new locus was assigned the name DFNB68. A 10 cM genome scan and additional fine mapping were carried out using microsatellite marker loci. Linkage was established for both families to DFNB68 with maximum multipoint LOD scores of 4.8 and 4.6. The overlap of the homozygous regions between the two families was bounded by D19S586 and D19S584, which limits the locus interval to 1.9 cM and contains 1.4 Mb. The genes CTL2, KEAP1 and CDKN2D were screened but were negative for functional sequence variants.