Confirmation of genetic heterogeneity in familial psoriasis.

Abstract

Psoriasis affects approximately 2% of the European population and is often familial. Linkage of a subset of psoriasis families to loci on chromosome 17q has recently been reported. We have studied members of a large multiply affected family from the north east of England and analysed genotypes for markers from 17q, including the polymorphic microsateilite markers AFM210xa5, AFM163ygl, AFMO44xg3, AFMa353ygl, and AFM217yd19. Two point and multipoint analysis clearly show exclusion of linkage between the telomeric region of 17q and psoriasis in this family. This confirms the genetic heterogeneity of psoriasis and the existence of at least one other major psoriasis locus. (JMed Genet 1995;32:546-

Analysis of Three Suggested Psoriasis Susceptibility Loci in a Large Swedish Set of Families: Confirmation of Linkage to Chromosome 6p (HLA Region), and to 17q, but not to 4q

“…Twin studies give a heritability factor of similar degree: 60-80% [10,11]. Psoriasis is a heterogeneous disease [12][13][14] and several modes of inheritance have been proposed [1,15]. We have shown that population genetic data for first-degree relatives are compatible with an autosomal recessive mode of inheritance with a gene frequency of 0.25 for a major gene [3,16].…”

“…Replicate studies failed to show linkage to the chromosome 4q region [18,19]. The region on chromosome 17 has been confirmed by one group [19] while other studies have failed to replicate the reported linkage [13,18]. Trembath et al [18] reported a genome scan on 66 affected sib pairs through which the authors had identified four potential psoriasis susceptibility loci, on chromosome 2p, chromosome 6p, chromosome 8q and chromosome 20p.…”

Familial Psoriasis and HLA-B: Unambiguous Support for Linkage in 97 Published Families

“…However, in recent years, there has been evidence – some of it conflicting – concerning possible linkage between psoriasis and other loci, notably, loci on chromosomes 4q and 17q. Concerning 17q, some studies [7, 8, 12] have reported positive evidence, whereas others [3, 9, 10] have reported negative evidence. Concerning 4q, Matthews et al [11] have reported positive, and Trembath et al [3] negative evidence.…”

“…The strongest candidate for location of a psoriasis susceptibility gene has been a region on chromosome 6p, near the HLA complex, because of the strong, consistent associations reported between psoriasis and certain HLA alleles, particularly B17 and Cw6 [4, 5, 6]. Other possible locations have been reported, particularly on chromosomes 17q and 4q, but follow-up reports have been conflicting [3, 7, 8, 9, 10, 11, 12]. Two recent studies have highlighted still other possible candidate regions [3, 12], but these remain to be confirmed or refuted.…”

Psoriasis susceptibility locus in chromosome region 3q21 identified in patients from southwest Sweden

“…Replication studies have been reported supporting the locus on 17q, 13,14 whereas other studies fail to confirm it. 15, 16 Matthews et al 17 reported a second psoriasis gene location on chromosome 4q using a dominant model with reduced penetrance. No other study has been able to confirm this locus.…”