Filaggrin-2 variation is associated with more persistent atopic dermatitis in African American subjects.

BACKGROUND: Atopic dermatitis (AD) is a common skin disease characterized by recurrent episodes of itching. Genetic variation associated with the persistence of AD has not been described for African American subjects. OBJECTIVE: We sought to evaluate genetic variation of filaggrin-2 (FLG2) in African American subjects with AD. METHODS: We evaluated a multiyear prospective cohort study of African American children with AD with respect to FLG2 variation based on whole-exome sequencing, followed by a targeted analysis. We ultimately evaluated the association of rs12568784 and rs16833974 with respect to the persistence of AD symptoms over time. RESULTS: Whole-exome analysis was conducted on 60 subjects, revealing a premature stop codon in exon 3 at S2377X (rs12568784) and X2392S (rs150529054) and a large exon 3 deletion mutation, Q2053del224. On the basis of a priori criteria, we then studied rs12568784, rs16833974 (H1249R), and Q2053del224. We noted that patients with S2377X (odds ratio [OR], 0.44; 95% CI, 0.25-0.46) and H1249R (OR, 0.23; 05% CI, 0.12-0.46) were significantly less likely to be free of symptoms of AD, and Q2053del224 (OR, 0.54; 95% CI, 0.16-1.80) trended toward this outcome. S2377X and H1249R were in high linkage disequilibrium (D' = 0.95). CONCLUSIONS: In an African American cohort with AD, FLG2 mutations were associated with more persistent AD. This is the first finding of genetic variation of a skin barrier protein in subjects of African ancestry with AD.

A genome-wide association study of breast cancer in women of African ancestry.

Genome-wide association studies (GWAS) in diverse populations are needed to reveal variants that are more common and/or limited to defined populations. We conducted a GWAS of breast cancer in women of African ancestry, with genotyping of >1,000,000 SNPs in 3,153 African American cases and 2,831 controls, and replication testing of the top 66 associations in an additional 3,607 breast cancer cases and 11,330 controls of African ancestry. Two of the 66 SNPs replicated (p < 0.05) in stage 2, which reached statistical significance levels of 10(-6) and 10(-5) in the stage 1 and 2 combined analysis (rs4322600 at chromosome 14q31: OR = 1.18, p = 4.3 × 10(-6); rs10510333 at chromosome 3p26: OR = 1.15, p = 1.5 × 10(-5)). These suggestive risk loci have not been identified in previous GWAS in other populations and will need to be examined in additional samples. Identification of novel risk variants for breast cancer in women of African ancestry will demand testing of a substantially larger set of markers from stage 1 in a larger replication sample.

The persistence of atopic dermatitis and filaggrin (FLG) mutations in a US longitudinal cohort.

BACKGROUND: Atopic dermatitis (AD) is a common skin disease that is characterized by recurrent episodes of itching. Filaggrin (FLG) loss-of-function (FLG null) mutations have been associated with an increased risk of AD. OBJECTIVE: We sought to evaluate the effect of individual FLG null mutations on the persistence of AD over time. METHODS: We evaluated a multiyear prospective cohort study of children with AD with respect to FLG null mutations (R501X, 2282del4, R2447X, and S3247X). We evaluated the association of these mutations with the persistence of AD symptoms over time with respect to reports of no symptoms of AD and whether topical medication was needed for symptom resolution. RESULTS: Eight hundred fifty-seven subjects were followed for 3684 person-years. One or more FLG null mutations were noted in 16.3% of subjects and specifically in 27.5% of white subjects and 5.8% of African American subjects. Subjects with an FLG null mutation were less likely (odds ratio [OR], 0.54; 95% CI, 0.41-0.71) to report that their skin was symptom free at any time compared with those without an FLG null mutation. The effect of these mutations was similar in white subjects (OR, 0.42; 95% CI, 0.31-0.57) and African-American subjects (OR, 0.53; 95% CI, 0.25-1.12; P = .62). Children with the R501X mutation (OR, 0.44; 95% CI, 0.22-0.88) were the least responsive to therapy. CONCLUSIONS: In a US cohort with AD, FLG null mutations were common. Children with FLG null mutations were more likely to have persistent AD. Although these mutations were more common in those of European ancestry, their effect on persistence was similar in those of African ancestry. Response to therapy was not uniform among children with FLG null mutations.

Pooled analysis indicates that the GSTT1 deletion, GSTM1 deletion, and GSTP1 Ile105Val polymorphisms do not modify breast cancer risk in BRCA1 and BRCA2 mutation carriers.

The GSTP1, GSTM1, and GSTT1 detoxification genes all have functional polymorphisms that are common in the general population. A single study of 320 BRCA1/2 carriers previously assessed their effect in BRCA1 or BRCA2 mutation carriers. This study showed no evidence for altered risk of breast cancer for individuals with the GSTT1 and GSTM1 deletion variants, but did report that the GSTP1 Ile105Val (rs1695) variant was associated with increased breast cancer risk in carriers. We investigated the association between these three GST polymorphisms and breast cancer risk using existing data from 718 women BRCA1 and BRCA2 mutation carriers from Australia, the UK, Canada, and the USA. Data were analyzed within a proportional hazards framework using Cox regression. There was no evidence to show that any of the polymorphisms modified disease risk for BRCA1 or BRCA2 carriers, and there was no evidence for heterogeneity between sites. These results support the need for replication studies to confirm or refute hypothesis-generating studies.