CARD14 alterations in Tunisian patients with psoriasis and further characterization in European cohorts.

BACKGROUND: Rare highly penetrant gain-of-function mutations in caspase recruitment domain family, member 14 (CARD14) can lead to psoriasis, a chronic inflammatory disease of the skin and other organs. OBJECTIVES: To investigate the contribution of rare CARD14 variants to psoriasis in the Tunisian population and to expand knowledge of CARD14 variants in the European population. METHODS: CARD14 coding exons were resequenced in patients with psoriasis and controls from Tunisia and Europe, including 16 European cases with generalized pustular psoriasis (GPP). Novel variants were evaluated for their effect on nuclear factor (NF)-κB signalling. RESULTS: Rare variants in CARD14 were significantly enriched in Tunisian cases compared with controls. Three were collectively found in 5% of Tunisian cases, and all affected the N-terminal region of the protein harbouring its caspase recruitment domain or coiled-coil domain. These variants were c.349G>A (p.Gly117Ser), c.205C>T (p.Arg69Trp) and c.589G>A (p.Glu197Lys). c.589G>A (p.Glu197Lys) led to upregulation of NF-κB activity in a similar manner to that of previously described psoriasis-associated mutations. p.Arg69Trp led to sevenfold downregulation of NF-κB activity. One Tunisian case harboured a c.1356+5G>A splice alteration that is predicted to lead to loss of exon 9, which encodes part of the coiled-coil domain. No cases of GPP harboured an interleukin-36RN mutation, but one of 16 cases of GPP with a family history of psoriasis vulgaris harboured a c.1805C>T (p.Ser602Leu) mutation in CARD14. CONCLUSIONS: These observations provide further insights into the genetic basis of psoriasis in the Tunisian population and provide functional information on novel CARD14 variants seen in cases from Tunisia and other populations.

Polymorphisms in VDR gene in Tunisian postmenopausal women are associated with osteopenia phenotype.

OBJECTIVES: Osteopenia is characterized by intermediate values of bone mineral density (BMD) as compared to normal and osteoporotic subjects. BMD, a surrogate phenotype for osteoporosis, is influenced in part by genetic factors. Among the genes associated with BMD, the vitamin D receptor (VDR) was the first gene studied as a potential candidate associated with BMD in adult and postmenopausal bone loss. However, results are controversial. METHODS: To determine whether VDR polymorphisms ApaI and TaqI are associated with BMD, osteopenia, osteoporosis and low-impact fracture risk in North Africans, these genotypes were analyzed in 566 postmenopausal Tunisian women. RESULTS: In postmenopausal Tunisian women, the GT ApaI genotype seems to be protective against osteoporosis development (p = 0.02; odds ratio = 0.54). Moreover, the presence of the combined GT/TT genotype of ApaI and TaqI polymorphisms is more frequent in normal BMD women than in osteoporotic women (p = 0.00; odds ratio = 0.41). Interestingly, the GG ApaI genotype is associated with osteopenia development (p = 0.02; odds ratio = 1.86) and also the TT TaqI polymorphism (p = 0.02; odds ratio = 1.53). The GG ApaI genotype is associated with a three times risk of vertebral fracture. CONCLUSIONS: The ApaI polymorphism showed an association with osteopenia and low-impact vertebral fracture incidence but not with osteoporosis. The TaqI polymorphism is associated specifically with the osteopenia phenotype. The presence of the two polymorphisms increases the risk to develop osteopenia in postmenopausal Tunisian women. Osteopenia seems to be genetically determined. However, osteoporosis is the result of interaction between genetic and environmental factors.

Failure to find evidence for deletion of LCE3C and LCE3B genes at PSORS4 contributing to psoriasis susceptibility in Tunisian families.

BACKGROUND: Recently, it has been shown that a deletion in the late cornified envelope (LCE) gene cluster (LCE3C_LCE3B-del) is associated with susceptibility to psoriasis in European and Asian populations. However, no study of this deletion has been performed in the North African population. The aim of the present study was to investigate whether this deletion is associated with familial psoriasis in Tunisian population. METHODS: A total of 34 patients and 55 healthy individuals were recruited from 7 multiplex families and a PCR assay was used to determine the association of this deletion. Its effect on susceptibility to psoriasis was assessed using the PDT program. RESULTS: We failed to detect any evidence of association between LCE3C_LCE3B-del and psoriasis in Tunisian families. No epistasic effect was found between the deletion and PSORS1 locus. CONCLUSIONS: These findings indicate that the LCE3C_LCE3B-del does not contribute in a major way to psoriasis susceptibility in Tunisian families.

Genome-wide linkage scan for psoriasis susceptibility loci in multiplex Tunisian families.

BACKGROUND: Psoriasis is a relapsing chronic inflammatory skin disease affecting all population groups, with a peak prevalence of 3% in northern European and Scandinavian caucasians. Epidemiological studies have implicated a genetic component to psoriasis. In the past 12 years multiple genome-wide linkage analyses have identified putative susceptibility loci on several chromosomes, with a major locus in the major histocompatibility complex region. OBJECTIVES: To investigate the genetic basis of familial psoriasis in the Tunisian population using a genome-wide linkage scan in seven ultiplex psoriatic families from Tunisia. METHODS: Following single nucleotide polymorphism (SNP) genotyping on the Affymetrix 10K SNP array, we performed nonparametric linkage (NPL) multipoint analyses to identify genotypes and obtain evidence for linkage with psoriasis across the genome. RESULTS: No chromosomal region gave consistent evidence for linkage, providing evidence for genetic heterogeneity in Tunisian psoriasis families. Significant evidence for linkage of psoriasis to chromosome 2p12 was seen in one family. We also identified several regions of tentative psoriasis linkage on chromosomes 2q, 4q, 6p, 11q, 12q, 9q and 13q. One family exhibiting suggestive evidence for linkage to 17q25 (PSORS2) was identified and all affected members harboured a p.Gly117Ser mutation in CARD14 (caspase recruitment domain family, member 14), recently reported to lead to psoriasis in a large family from the U.S.A. CONCLUSIONS: Our results support the genetic heterogeneity of psoriasis in the Tunisian population, provide confirmatory evidence for a novel psoriasis locus at chromosome 2p12 and reveal a psoriasis family with a mutation at PSORS2.

[Familial psoriasis: descriptive report of 9 families]. / Le psoriasis familial: etude descriptive à propos de 9 familles.

BACKGROUND: Psoriasis is a chronic inflammatory skin disease. The familial nature of psoriasis has long been recognized. Aim of our study was to describe the epidemiological, clinical and genetic features of familial psoriasis. METHODS: Through a prospective study we investigated during a study period of lyear (2006-2007) 9 Tunisian unrelated multiplex families. Patients with psoriasis and their available family members were examined by the same dermatologist. RESULTS: Thirty nine individual presented psoriasis (25 men and 4 women), with a mean age at onset about 19.8 years. With the systematic exam of member's family we discover 11 cases of unknown psoriasis. The common form of psoriasis was the preponderant one (37 cases). The nails, the scalp, the mucous membranes were involved respectively in 21, 12 and 13 cases. The psoriasis was severe in 11 cases. CONCLUSION: Through this study we find similar epidemiological and clinical features of those reported previously. The intra and inter-familial variability was evident in our patients.

Contribution of the BRCA1 and BRCA2 mutations to breast cancer in Tunisia.

Hereditary breast cancer accounts for 3-8% of all breast cancers, with mutations in the BRCA1 and BRCA2 genes responsible for up to 30% of these. To investigate the prevalence of BRCA1 and BRCA2 gene mutations in breast cancer patients with affected relatives in Tunisia, we studied 36 patients who had at least one first degree relative with breast and/or ovarian cancer Thirty-four 34 patients were suggestive of the BRCA1 mutation and two were suggestive of the BRCA2 mutation, based on the presence of male breast cancer detected in their corresponding pedigrees. Four mutations in BRCA1 were detected, including a novel frame-shift mutation (c.211dupA) in two unrelated patients and three other frameshift mutations--c.4041delAG, c.2551delG and c.5266dupC. Our study is the first to describe the c.5266dupC mutation in a non-Jewish Ashkenazi population. Two frameshift mutations (c.1309del4 and c.5682insA) were observed in BRCA2. Nineteen percent (7/36) of the familial cases had deleterious mutations of the BRCA1 or BRCA2 genes. Almost all patients with deleterious mutations of BRCA1 reported a family history of breast and/or ovarian cancer in the index case or in their relatives. Our data are the first to contribute to information on the mutation spectrum of BRCA genes in Tunisia, and we give a recommendation for improving clinical genetic testing policy.