Familial Primary Cutaneous Amyloidosis Research Articles

Mutation analysis of the OSMR gene in a family with familial primary cutaneous amyloidosis

Objective To identify mutations in the OSMR gene in a pedigree with familial primary cutaneous amyloidosis (FPCA).Methods Clinical data were collected from a pedigree with FPCA.Peripheral blood samples were obtained from the proband,his 19 relatives,and 50 unrelated healthy human controls.Genomic DNA was extracted from these blood samples,and subjected to PCR for the amplification of 18 encoding exons and their flanking sequences of the OSMR gene followed by DNA sequencing.Results A heterozygous missense mutation c.2081C ＞ T,which leads to the substitution of proline by threonine at position 694,was detected in the OSMR gene of the proband and his affected relatives,but not in unaffected relatives or healthy controls.Conclusion The heterozygous mutation p.P694L in the OSMR gene may cause the clinical phenotype of FPCA in this family. Key words: Amyloidosis, familial; Gene, OSMR; Mutation, missense

Identification of MCP-1 as a Key Effector of IL-31 Signaling in Familial Primary Cutaneous Amyloidosis

Identification of MCP-1 as a Key Effector of IL-31 Signaling in Familial Primary Cutaneous Amyloidosis

Novel IL31RA gene mutation and ancestral OSMR mutant allele in familial primary cutaneous amyloidosis

Primary cutaneous amyloidosis (PCA) is an itchy skin disorder associated with amyloid deposits in the superficial dermis. The disease is relatively common in Southeast Asia and South America. Autosomal dominant PCA has been mapped earlier to 5p13.1-q11.2 and two pathogenic missense mutations in the OSMR gene, which encodes the interleukin-6 family cytokine receptor oncostatin M receptor beta (OSMRbeta), were reported. Here, we investigated 29 Taiwanese pedigrees with PCA and found that 10 had heterozygous missense mutations in OSMR: p.D647V (one family), p.P694L (six families), and p.K697T (three families). The mutation p.P694L was associated with the same haplotype in five of six families and also detected in two sporadic cases of PCA. Of the other 19 pedigrees that lacked OSMR pathology, 8 mapped to the same locus on chromosome 5, which also contains the genes for 3 other interleukin-6 family cytokine receptors, including interleukin-31 receptor A (IL31RA), which can form a heterodimeric receptor with OSMRbeta through interleukin-31 signaling. In one family, we identified a point mutation in the IL31RA gene, c.1562C>T that results in a missense mutation, p.S521F, which is also sited within a fibronectin type III-like repeat domain as observed in the OSMR mutations. PCA is a genetically heterogeneous disorder but our study shows that it can be caused by mutations in two biologically associated cytokine receptor genes located on chromosome 5. The identification of OSMR and IL31RA gene pathology provides an explanation of the high prevalence of PCA in Taiwan as well as new insight into disease pathophysiology.

Identification of an oncostatin M receptor mutation associated with familial primary cutaneous amyloidosis

Identification of an oncostatin M receptor mutation associated with familial primary cutaneous amyloidosis

Genome-wide scan identifies a susceptibility locus for familial primary cutaneous amyloidosis on chromosome 5p13.1-q11.2

Primary cutaneous amyloidosis (PCA) is a relatively common skin disorder in South America and Southeast Asia. Most cases of PCA are sporadic but familial aggregation has been reported from South America and Taiwan. The different susceptibility among ethnic groups suggests that genetic factors may play an important role in its pathogenesis. We aimed to perform a genome-wide scan by linkage analysis across 15 families with familial primary cutaneous amyloidosis (FPCA) to map the disease gene(s) for FPCA. A total of 15 FPCA families including 50 individuals affected with PCA were recruited. Throughout the 22 autosomes, 369 polymorphic microsatellite markers were used initially. Regions showing a LOD score > 1 identified in the initial scan were further analysed with additional markers. Two-point and multipoint linkage analysis were performed by using the LINKAGE program. Nonparametric linkage (NPL) analysis and reconstruction of haplotypes were performed with the GENEHUNTER program. A maximum two-point LOD score of 4.76 for the marker D5S1490 (theta = 0.10, alpha = 0.60) and a multipoint LOD score of 4.50 between D5S822 and D5S623 (alpha = 0.60) were obtained under the assumption of heterogeneity. A peak NPL score of 5.23 (P value = 0.000007) was found from D5S1490 to D5S2076. Further analysis focusing on two major families identifies a common haplotype shared by all affected individuals between D5S1490 and D5S623. To our knowledge, this is the first report of genome-wide analysis of a large number of FPCA pedigrees. Our study provides evidence for significant linkage to chromosome 5p13.1-q11.2 in a subset of FPCA families.

Suggestive linkage of familial primary cutaneous amyloidosis to a locus on chromosome 1q23

There is a high incidence of primary cutaneous amyloidosis (PCA) in South America, South-east Asia and Taiwan. To date, the aetiology of PCA remains unknown, but it is believed to be multifactorial. Although most cases are sporadic, some patients have a family history. Familial aggregation and different susceptibility to PCA among ethnic groups suggest that genetic factors may play an important role in its pathogenesis. However, no genetic loci for familial PCA (FPCA) have been identified so far. In order to identify the susceptibility gene of FPCA, we took a candidate gene approach and performed linkage analysis on chromosome 1q21.3-24.2, including the 1q23.2 region where the gene encoding serum amyloid P component (APCS) is located. Nine FPCA families including 29 individuals affected with PCA were recruited for this linkage study. Initially, 11 highly polymorphic microsatellite markers spanning the region from 1q21.3 to 1q24.2 were genotyped and revealed a suggestive linkage region. This region was further fine-mapped with seven additional markers. We also re-sequenced the 2.5-kb genomic region of the APCS gene in 29 affected and 42 control individuals. Two-point and multipoint linkage analyses were performed using the LINKAGE program. Nonparametric linkage (NPL) analysis and reconstruction of haplotypes were performed with the GENEHUNTER program. Both two-point and multipoint linkage analysis for all 11 markers generated negative or small positive total lod scores for all nine families. However, when we considered only three families, a maximum two-point total lod score of 2.09 was obtained for the marker D1S2844 at theta = 0.01. A plateau of multipoint total lod score between D1S2768 and D1S2878 with a maximum of 2.48 at the marker D1S2844 was observed. A maximum NPL score of 3.11 (P = 0.008) was also obtained for the marker D1S2878. However, re-sequencing of the APCS gene identified no functional mutation. Both parametric and nonparametric linkage evidence suggested that a possible susceptibility locus for a subset of FPCA might exist on chromosome 1q23. This is the first report demonstrating suggestive evidence of linkage of FPCA to a locus in this candidate region. No functional sequence variations of the APCS gene were found to be associated with this disease among the study families. Our data imply the existence of at least one additional locus responsible for FPCA in these families, confirming genetic heterogeneity of this skin disorder.

Genetic Heterogeneity of Familial Primary Cutaneous Amyloidosis: Lack of Evidence for Linkage with the Chromosome 10 Pericentromeric Region in Chinese Families

Primary cutaneous amyloidosis is a relatively common skin disease in Southeast Asia, South America, and the Republic of China. Although most cases are sporadic, some patients have a family history, suggesting that genetic factors may play a role in its pathogenesis. Some patients with multiple endocrine neoplasia type 2A also have a clinical picture of primary cutaneous amyloidosis. It is thus suggested that the gene of familial primary cutaneous amyloidosis is linked to the pericentromeric region of chromosome 10, the location of the RET proto-oncogene. We have carried out linkage analysis in seven families with cutaneous amyloidosis using four dinucleotide repeat markers from the RET region. Negative lod scores at all recombination frequencies were obtained. We thus conclude that there is no evidence for linkage between Chinese families with primary cutaneous amyloidosis and the pericentromeric region of chromosome 10. The distinct genetic basis, plus their apparent phenotypic differences in sex ratio, age of onset, and sites of cutaneous lesions, suggests that familial primary cutaneous amyloidosis includes clinical subtypes attributable to genetic heterogeneity.

Familial primary cutaneous amyloidosis. Clinical, genetic, and immunofluorescent studies

Familial primary cutaneous amyloidosis. Clinical, genetic, and immunofluorescent studies

Familial Primary Cutaneous Amyloidosis

Familial primary cutaneous amyloidosis, a rare, autosomal dominant genodermatosis, affected 16 of 46 family members of German descent. Previous case reports involved families of Russian, Spanish, or Chinese descent. The finding of IgG, IgM, C3 in the amyloid deposits confirms recent reports of immunofluorescent dermal amyloid deposits.