Under-recognition of acral peeling skin syndrome: 59 new cases with 15 novel mutations.

BACKGROUND: Acral peeling skin syndrome (APSS) is a rare skin fragility disorder usually caused by mutations in the transglutaminase 5 gene (TGM5). METHODS: We investigated the mutation spectrum of APSS in the U.K., Germany and Poland. RESULTS: We identified 59 children with APSS from 52 families. The phenotype was readily recognizable, with some variation in severity both within and between families. Most cases had been misdiagnosed as the localized form of epidermolysis bullosa simplex (EBS-loc). Eighteen different TGM5 mutations were identified, 15 of which were novel. Eight mutations were unique to a single family, nine each occurred in two families, while the common p.Gly113Cys mutation linked to a second missense variant p.Thr109Met occurred in 47 of the 52 families and was homozygous in 28. Most patients were of nonconsanguineous white European origin. CONCLUSIONS: We propose that APSS is under-reported and widely misdiagnosed as EBS-loc, with significant counselling implications as APSS is autosomal recessive while EBS-loc is dominant. We recommend screening for TGM5 mutations when EBS-loc is suspected but not confirmed by mutations in KRT5 or KRT14. Our report trebles the number of known TGM5 mutations. It provides further evidence that p.Gly113Cys is a founder mutation in the European population. This is consistent with the striking ethnic distribution of APSS in U.K., where the majority of patients are of nonconsanguineous white European origin, in contrast to the pattern of other recessive skin disorders.

Racial differences in mycosis fungoides: a retrospective study with a focus on eosinophilia.

BACKGROUND: Mycosis fungoides (MF) is often associated with eosinophilia and portends a poorer prognosis. MF is more common in blacks and follows a more aggressive course compared with whites. OBJECTIVE: We further elucidate racial differences between blacks and whites with MF, focusing on blood eosinophilia. METHODS: The records of 345 patients with MF were reviewed for demographic, clinical, and pathologic data and evaluated by analysis of variance. RESULTS: The average age at diagnosis for blacks was 45 years and was 55 years for white patients (P < .001). In the cohorts of patients with and without blood eosinophilia, the average maximum blood eosinophil count had a greater range in blacks. Independent of race, blood eosinophilia was predictive of more advanced disease (P < .0001), increased number of treatment types (P < .002), and less responsiveness to treatment (P < .0006). LIMITATIONS: This was a retrospective study at a single institution. CONCLUSIONS: These differences observed in eosinophil values may highlight disparities in MF diagnosis or a difference in pathophysiology between races.

Strong founder effect for a transglutaminase 1 gene mutation in lamellar ichthyosis and congenital ichthyosiform erythroderma from Norway.

Autosomal recessive congenital ichthyosis (ARCI) is a clinically heterogeneous disorder of keratinisation. It was recently shown that mutations in the transglutaminase 1 (TGM1) gene may be associated with the clinical subtypes lamellar ichthyosis (LI) and non-bullous congenital ichthyosiform erythroderma (CIE). Thirty-six Norwegian families with LI and seven with non-bullous CIE were studied with microsatellite markers linked to the TGMI gene. One common haplotype for two markers was found on 74% of disease associated chromosomes. Three individuals homozygous for the common haplotype, two affected by LI and one affected by CIE, were analysed for mutations in the TGM1 gene. All three patients were found homozygous for a single A to G transition located in the canonical splice acceptor site of intron 5. Probands from the remaining 40 families with LI and CIE were screened for this mutation and the A to G transition was found on 61 out of 72 alleles associated with LI and on 9 out of 15 alleles associated with CIE. These findings suggest a single founder mutation for the majority of patients with LI and CIE in Norway. The 2526A-->G mutation results in the insertion of a guanosine at position 877 (876insG) in the mature cDNA and the frame shift creates a premature termination at codon 293. The mutation was previously observed in one family with a resulting cDNA that included the entire intron 5. These results suggest that the mutation can result in variant transcripts in different individuals.