Associations of a novel IL4RA polymorphism, Ala57Thr, in Greenlander Inuit

BACKGROUND

A novel IL4RA polymorphism, Ala57Thr, was identified in Greenlander Inuit.

OBJECTIVE

We sought to determine whether the novel Thr57 allele is population specific and to assess the associations of Ala57Thr and Ile50Val with atopy in 2 Inuit populations.

METHODS

Ala57Thr and Ile50Val were genotyped in 651 Inuit living in Denmark, 1295 Inuit living in Greenland, and 1329 individuals from 7 populations from widely differing global locations. In Inuit the polymorphisms were evaluated for associations with atopy, rhinitis, asthma, and pulmonary function.

RESULTS

Thr57 was in linkage disequilibrium with Ile50 (D' = 1, r(2) = 0.13) and was common (33%) in the Inuit but rare (<0.6%) in all other populations. In Inuit living in Denmark, the Thr57 allele (in a dose-dependent manner) and the Ile50/Thr57 haplotype were associated with lower risk of atopy (P(linear) = .003 and P = .034, respectively), with similar trends observed for atopic rhinitis and atopic asthma. In Inuit living in Greenland, Thr57 was not associated with atopy or atopic diseases, but Ile50 was weakly associated with lower risk of atopy.

CONCLUSION

The novel IL4RA Ala57Thr was common in and population specific to Greenlander Inuit, with Thr57 associated with a lower risk of atopy in those living in Denmark. Hence a full investigation of genotype-phenotype relationships in a given population can only be achieved if each gene is screened for novel polymorphisms in that population.

CLINICAL IMPLICATIONS

Clinical risk attributable to variations in a gene in an ethnic group requires that all variations of the gene are known for that group.

Deletion Mutations in an Australian Series of HNPCC Patients

Hereditary non polyposis colorectal cancer (HNPCC) is characterized by the presence of early onset colorectal cancer and other epithelial malignancies. The genetic basis of HNPCC is a deficiency in DNA mismatch repair, which manifests itself as DNA microsatellite instability in tumours. There are four genes involved in DNA mismatch repair that have been linked to HNPCC; these include hMSH2, hMLH1, hMSH6 and hPMS2. Of these four genes hMLH1 and hMSH2 account for the majority of families diagnosed with the disease. Notwithstanding, up to 40 percent of families do not appear to harbour a change in either hMSH2 or hMLH1 that can be detected using standard screening procedures such as direct DNA sequencing or a variety of methods all based on a heteroduplex analysis.In this report we have screened a series of 118 probands that all have the clinical diagnosis of HNPCC for medium to large deletions by the Multiplex Ligation-Dependent Probe Amplification assay (MLPA) to determine the frequency of this type of mutation. The results indicate that a significant proportion of Australian HNPCC patients harbour deletion or duplication mutations primarily in hMSH2 but also in hMLH1.

Nursing as a career choice: perceptions of school students speaking Arabic, Serbo-Croatian, Spanish, Turkish or Vietnamese at home

Australia is a multicultural society and nowhere is this more evident than in Sydney where 25% of the population speaks a language other than English. In one of the largest area health services in New South Wales, the five most frequently spoken languages at home are Arabic, Serbo-Croatian, Spanish, Turkish or Vietnamese, with these language groups comprising 12% of Sydney's population. Yet nurses speaking one of these five languages comprise less than 1% of the nursing workforce. A cost-effective method of addressing the shortage of nurses speaking languages other than English is to recruit students who already speak another language into the profession. This study examined high school students' perceptions of nursing in order to determine appropriate methods of recruiting students speaking one of these languages. Implications for the design of recruitment campaigns are also discussed.

Predictors of intention to study nursing among school students speaking a language other than English at home

There is currently a shortage of bilingual nurses in New South Wales. It is important to include bilingual nurses in the workforce to meet not only the cultural and social needs of people speaking a language other than English at home, but also to facilitate the achievement of appropriate health outcomes for a multicultural population. The purpose of this study was to identify demographic and social factors which explain students' intention to study nursing. Respondents were 789 year 11 or 12 students speaking Arabic, Serbo-Croatian, Spanish, Turkish or Vietnamese from twenty-five schools in South Eastern, South Western and Western Sydney. Data were collected through a self-completed questionnaire. Chi square, t-test and logistic regression analysis were used for data analysis. Logistic regression analysis concluded that perceived parental income, years of settlement in Australia and father's occupation were significant factors. Bivariate analysis also revealed that significant differences were found in the intention to study nursing between male and female students and between students with a higher and lower Tertiary Entrance Rank (TER). Parental influence also affects students' intention. However, gender and TER were found to be insignificant after adjustment for other variables in the logistic regression model.

Genetic counselling and gene mutation analysis in familial adenomatous polyposis in Western Australia

OBJECTIVE

To assess the provision of accurate pre-symptomatic genetic testing with DNA analysis and appropriate counselling for individuals and families known to be at high risk of developing familial adenomatous polyposis coli (FAP).

PATIENTS AND METHODS

Thirty-one families with clinically and pathologically documented FAP were ascertained from the Western Australian Polyposis Registry. DNA was collected from over 200 individuals in these families to establish their genetic risk status for FAP, either by direct mutation analysis, or by linkage analysis. Individuals undergoing DNA testing were given intensive psychosocial support and counselling.

RESULTS

In 19 families DNA-based counselling could not be offered because either the adenomatous polyposis coli (APC) gene mutation could not be detected or there were insufficient family members for linkage analysis. Gene testing yielded mutations of the APC gene in 87 individuals from 12 families; by gene tracking (or linkage analysis) in three families and by mutation analysis in the remaining nine (four of which had only one affected individual). DNA results conformed with a definite clinicopathological diagnosis in 27 FAP patients and, of the remaining 60 high-risk subjects tested, 14 had inherited the mutated APC gene.

CONCLUSIONS

DNA analysis allowed accurate genetic counselling for 12 of 31 families affected by FAP, thus improving the medical and personal management in asymptomatic people who would otherwise be subjected to the uncertainty of long term surveillance and repeated colonic examinations. In future a superior biomolecular approach to gene mutation analysis, such as the protein truncation test, will facilitate management for most FAP individuals and families.

Mutation analysis of Western Australian families affected by cystic fibrosis

OBJECTIVE

To document the results of mutation analysis on 160 individuals with cystic fibrosis and 31 obligate carriers of the cystic fibrosis gene in 191 Western Australian families to facilitate accurate genetic counselling.

METHODS

We tested for 17 mutations of the cystic fibrosis gene by either a variation of the polymerase chain reaction amplification refractory mutation system (PCR-ARMS) or with a series of restriction enzyme cuts and dot blots using chemiluminescent probes.

RESULTS

At least one of the two intragenic mutations causing cystic fibrosis was identified in 98% of affected individuals and both were detected in 68%. The delta F508 deletion occurred in 89.8% of patients: 51% were homozygous for this defect. In carriers, 85% of the mutations were detected with a panel of 16 probes, identifying 17 intragenic defects: the delta F508 deletion occurred in 72.4%. Both cystic fibrosis mutations were detected in 68% of cystic fibrosis families.

CONCLUSIONS

By analysis with 16 intragenic cystic fibrosis genomic probes, we have documented the frequencies of various mutations in the Western Australian population. These data will be useful in accurate genetic counselling for affected families and carrier screening for the general population.