Erythrokeratodermia Variabilis-like Phenotype in Patients Carrying ABCA12 Mutations.

Erythrokeratodermia variabilis (EKV) is a rare genodermatosis characterized by well-demarcated erythematous patches and hyperkeratotic plaques. EKV is most often transmitted in an autosomal dominant manner. Until recently, only mutations in connexins such as GJB3 (connexin 31), GJB4 (connexin 30.3), and occasionally GJA1 (connexin 43) were known to cause EKV. In recent years, mutations in other genes have been described as rare causes of EKV, including the genes KDSR, KRT83, and TRPM4. Features of the EKV phenotype can also appear with other genodermatoses: for example, in Netherton syndrome, which hampers correct diagnosis. However, in autosomal recessive congenital ichthyosis (ARCI), an EKV phenotype has rarely been described. Here, we report on seven patients who clinically show a clear EKV phenotype, but in whom molecular genetic analysis revealed biallelic mutations in ABCA12, which is why the patients are classified in the ARCI group. Our study indicates that ARCI should be considered as a differential diagnosis in EKV.

Pustular psoriasis of pregnancy: Clinical and genetic characteristics in a series of eight patients and review of the literature.

Pustular psoriasis of pregnancy (PPP) can lead to life-threatening complications. The objective of this study is to report clinical and genetic spectrum, prognostic factors and management options. A retrospective study was designed including eight PPP patients. Clinical data were collected, and performed genetic and statistical analysis to identify factors associated with fetal complications, resistance to treatment and post-partum flare extension. A systematic review of the literature was also carried out. Eight Tunisian patients, with a mean age of 23 ± 3.3 years, were included. They presented 14 flares (F) during pregnancies and one flare after delivery. Additional GPP flares outside pregnancy periods were noted in 2/8 of patients. The mean duration of PPP flares was 16.66 ± 7.8 weeks. The first flare occurred at a gestational age of 26 ± 5 weeks. Only 2/8 studied patients presented a homozygous mutation c.80 T > C (p.L27P) in IL36RN gene. Used treatments were topical steroids (n = 12F), systemic steroids (n = 5F), ciclosporin (n = 1F), UVB (n = 1F) and acitretin (in post-partum n = 6F). Complications were oligoamnios (n = 2), intra-uterine growth retardation (n = 1), fetal death in utero (n = 1), prematurity (n = 3), low weight at birth (n = 2). A significant association was found between (i) occurrence of fetal complications and early gestational age at the onset (p = 0.036), (ii) resistance to topical steroids and body surface affected area (p = 0.008), (iii) presence of mutation c.80 T > C in PPP flares and low serum levels of calcium (p = 0.01). Our systematic review of the literature identified 39 patients with 41 flares of PPP. Only 7/39 patients presented a causative mutation in IL36RN and CARD14 genes. PPP is characterized by a phenotypic heterogeneity and can be associated to IL36RN mutations. Its early onset can be associated with fetal complications. Systemic steroids and cyclosporine remain the most used therapies.

Clinical and genetic investigation of ichthyosis in familial and sporadic cases in south of Tunisia: genotype-phenotype correlation.

BACKGROUND: Ichthyosis is a heterogeneous group of Mendelian cornification disorders that includes syndromic and non-syndromic forms. Autosomal Recessive Congenital Ichthyosis (ARCI) and Ichthyosis Linearis Circumflexa (ILC) belong to non-syndromic forms. Syndromic ichthyosis is rather a large group of heterogeneous diseases. Overlapping phenotypes and genotypes between these disorders is a major characteristic. Therefore, determining the specific genetic background for each form would be necessary. METHODS: A total of 11 Tunisian patients with non-syndromic (8 with ARCI and 2 with ILC) and autosomal syndromic ichthyosis (1 patient) were screened by a custom Agilent HaloPlex multi-gene panel and the segregation of causative mutations were analyzed in available family members. RESULTS: Clinical and molecular characterization, leading to genotype-phenotype correlation in 11 Tunisian patients was carried out. Overall, we identified 8 mutations in 5 genes. Thus, in patients with ARCI, we identified a novel (c.118T > C in NIPAL4) and 4 already reported mutations (c.534A > C in NIPAL4; c.788G > A and c.1042C > T in TGM1 and c.844C > T in CYP4F22). Yellowish severe keratoderma was found to be associated with NIPAL4 variations and brachydactyly to TGM1 mutations. Two novel variations (c.5898G > C and c.2855A > G in ABCA12) seemed to be features of ILC. Delexon13 in CERS3 was reported in a patient with syndromic ichthyosis. CONCLUSIONS: Our study further extends the spectrum of mutations involved in ichthyosis as well as clinical features that could help directing genetic investigation.

Identification of a novel missense mutation in NIPAL4 gene: First 3D model construction predicted its pathogenicity.

BACKGROUND: The NIPAL4 gene is described to be implicated of Congenital Ichthyosiform Erythroderma (CIE). It encodes a magnesium transporter membrane-associated protein, hypothetically involved in epidermal lipid processing and in lamellar body formation. The aim of this work is to investigate the causative mutation in a consanguineous Tunisian family with a clinical feature of CIE with a yellowish severe palmoplantar keratoderma. METHODS: Four patients were dignosed with CIE. The blood samples were collected from patients and all members of their nuclear family for mutation analysis. The novel mutation of NIPAL4 gene was analysed with several software tools to predict its pathogenicity. Then, the secondary structure and the 3D model of ichthyn was generated in silico. RESULTS: The sequencing analysis of the NIPAL4 gene in patients revealed a novel homozygous missense mutation c.534A>C (p.E178D) in the exon 4. Bioinformatic tools predicted its pathogenicity. The secondary structure prediction and the 3D model construction expected the presence of 9 transmembrane helices and revealed that mutation p.E178D was located in the middle of the second transmembrane helices. Besides, the 3D model construction revealed that the p.E178D mutation is inducing a shrinking in the transport channel containing the mutated NIPA4 protein. CONCLUSION: We found a homozygous mutation in exon 4 of NIPAL4 c.534A>C (p.E178D), which was identified for the first time in our study. Bioinformatic investigations supported its involvement in the phenotype of patients with CIE. Interestingly, this mutation was located in the hypothetical transport channel cavity and leads to changes in the channel architecture, which would probably affect its transport function.