Mutation analysis and prenatal diagnosis of keratin 9 gene in a large Chinese family with epidermolytic palmoplantar keratoderma / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze potential mutation in keration 9 (KRT9) gene in a large Chinese family with epidermolytic palmoplantar keratoderma (EPPK) and to perform prenatal diagnosis on the fetus at 10th gestational week.</p><p><b>METHODS</b>Peripheral venous blood samples were obtained from 5 affected and 8 unaffected individuals of the family. Fifty unrelated healthy individuals were also recruited as controls. PCR was used to amplify exons 1 and 6 of KRT9 gene, and the products were sequenced directly. After the mutation was confirmed, prenatal diagnosis was performed on the fetus during the first trimester of pregnancy.</p><p><b>RESULTS</b>A heterozygous missense mutation c.482A to G in the KRT9 gene, which has led to substitution of Asparaginate by Serine at codon 161 (p.N161S), was detected in all patients but not in other individuals of the family and the 50 healthy controls. The fetus was found to have carried the p.N161S mutation too. Following selected abortion, analysis of fetal tissue was consistent with prenatal diagnosis.</p><p><b>CONCLUSION</b>The missense mutation c.482A to G (p.N161S), which has been shown previously to cause EPPK, is found in the KRT9 gene of patients in this family. Gene mutation analysis for prenatal diagnosis is efficient to facilitate detection of affected fetus in time.</p>

Mutation analysis of keratin 9 gene in a family with epidermolytic palmoplantar keratoderma / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze potential mutation of keration 9 gene (KRT9) in a Chinese family affected with epidermolytic palmoplantar keratoderma (EPPK) and to correlate genotype with the phenotype.</p><p><b>METHODS</b>Genomic DNA was extracted from peripheral blood samples of 12 patients and 13 healthy individuals from the family and 100 unrelated individuals. Polymerase chain reaction (PCR) was used to amplify exons 1 and 6 of KRT9 gene. PCR products were sequenced bidirectionally in order to identify potential mutations.</p><p><b>RESULTS</b>A heterozygous transversional mutation, 488G→A, was identified in exon 1 of KRT9 gene in all patients, which has resulted in substitution of a glutamine residue for arginine acid at position 163 (R163Q) of the KRT9 protein. The same mutation was not found in the 13 healthy members from the family and 100 unrelated individuals.</p><p><b>CONCLUSION</b>The 488G→A mutation of KRT9 gene is probably the cause of EPPK in this Chinese family.</p>

Bullous congenital ichthyosiform erythroderma: a case report

We report the case of a 16 year old male patient who presented to the dermatology clinic with spiny hyperkeratosis in flexural areas and palmoplantar keratoderma. The patient gave history of occasional localized blisters formation. Clinical findings and the histopathological picture fit the diagnosis of Bullous Congenital Ichthyosiform Erythroderma. Family history is also positive for the same disease

Mutation analysis of a Uighur family with epidermolytic palmoplantar keratoderma / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To map and identify the disease gene for the epidermolytic palmoplantar keratoderma (EPPK) in a Uighur family of China.</p><p><b>METHODS</b>Blood samples were collected and genomic DNA was extracted from 48 members of the Xinjiang Uighur family. Six microsatellite repeat sequences on chromosome region 17q12-q21 and 12q13 were selected based on the two known candidate genes KRT9 and KRT1. Two-point linkage analysis and haplotype analysis were performed. Exons and their flanking intronic sequence of the KRT9 gene were amplified by polymerase chain reaction (PCR) and sequenced.</p><p><b>RESULTS</b>Data from the marker D17S1787 suggested linkage and yielded a Lod score of 8.65 at theta=0 by using MLINK software. Genotypes and haplotypes were acquired. The disease gene of the EPPK family is located between markers 17/TG/36620115 and D17S846. Chromosome 12q13 region was excluded with the negative Lod score obtained in marker D12S96 (Lod=-infinity at theta=0). No pathogenic mutation was detected in the KRT9 gene.</p><p><b>CONCLUSION</b>The disease gene of the EPPK family is located on chromosome region 17q21.2. The keratin 9 gene might not be the disease gene.</p>

Present status of the molecular genetics in epidermolytic palmoplantar keratoderma / 中华医学遗传学杂志

In this article we reviewed the current researches on the molecular basis of epidermolytic palmoplantar keratoderma (EPPK) and the structure and function of the keratins with mutations that can cause inherited keratin disorders. Also summarized are seventeen mutations of keratin 9 in EPPK in different ethnic populations.

A case of Hereditary Epidermolytic Palmoplantar Keratoderma / 대한피부과학회지

The hereditary epidermolytic palmoplantar keratoderma (Vorner"s kerato derma) is characterized by autosomal dominantly inherited, marked, symmetrical thickening of the palms and soles. The presence of epidermolytic hyperkeratosis in skin biopsy differentiates hereditary epidermolytic palmoplantar keratoderma from Unna-Thost keratoderma. We report a case of hereditary epidermolytic palmoplantar keratoderma with literature reviews focused on the differential points from other palmoplantar keratodermas.

A Case of Epidermolytic Palmoplantar Keratoderma / 대한피부과학회지

Palmoplantar keratodermas are divided into autosomal dominant and autosomal recessive groups by the mode of transmission. The autosomal dominantly transmitted group is further divided into epidermolytic and nonepidermolytic types according to the histological findings. Hereditary epidermolytic palmoplantar keratoderma manifests clinically as a localized thickening of the palms and soles. Herein we report a 29-year-old woman showing the typical clinical and histologic features of epidermolytic palmoplantar keratoderma without family history. This case could be spontaneous mutations that will later breed a true autosomal dominant trait.

DNA-based Prenatal Diagnosis of Epidermolytic Palmoplantar Keratoderma in Two Pregnancies at Risk in One large Pedigree

BACKGROUND: Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant disease of cornification which presents as severe thickening of the palms and soles with prominent epidermolytic hyperkeratosis pathologically. Recent studies have shown that EPPK is caused by mutations in the keratin 9 (K9) gene which is expressed essentially only in the palms and soles. Previously, We have reported that patients in one large pedigree of EPPK have an R162W substitution in the K9 protein. In this pedigree, two women whose husbands are both EPPK patients had become pregnant. OBJECTIVE: Since both women were concerned about this genetic disorder, we have performed prenatal diagnosis by biopsy analysis of chorionic villi tissue. METHODS: Chorionic villi biopsies were performed at 12 weeks gestation. Since the skin lesions are strictly confined to the palms and soles of the babies, the prenatal diagnosis of EPPK by ultrastructural analysis of fetal skin biopsy or amniotic fluid cells is highly problematic. Polymerase chain reaction amplification of specific allele (PASA) assay and direct DNA sequencing analyses were performed whether the fetuses carried mutant allele of K9 gene. RESULTS: PASA assay and direct DNA sequencing analyses showed that one fetus was normal, but the other fetus carried the abnormal allele. Subsequently, the mother of the unaffected fetus delivered a normal child, but the mother of the affected fetus terminated the pregnancy. CONCLUSION: We describe the analysis of the K9 mutation in the two fetuses at risk for EPPK. We believe that this is the first report of prenatal diagnosis for EPPK. But, we have to think about the ethical problems before we decide to perform the prenatal diagnosis of any kind of skin diseases.

A Case of Hereditary Epidermolytic Palmoplantar Keratoderma in Four Consecutive Generations / 대한피부과학회지

We observed a family with 12 members in four consecutive generations affected by hereditary epidermolytic palmoplantar keratoderma(HEPPK). The affected family members demonstrated not only autosomal dominant inheritance, but also a high penetrance and constant expression. The lesion of all affected person had developed at birth or within the first few weeks of life. The lesions of three members(the proband, her sister and mother) were biopsed, and all of them showed the characteristic features of epidermolytic hyperkeratosis. Two of family members(the proband, her nephew-not affected by HEPPK) had vitiligo, but we concluded that this coexistance was accidental.

DNA - based Prenatal Diagnosis of Epidermolytic Palmoplantar Keratoderma / 대한산부인과학회잡지

OBJECTIVE: The purpose of this investigation was to establish the prenatal diagnosis for identifying the risk for epidermolytic palmoplantar keratoderma(EPPK) of a fetus by sequence analysis of fetal genomic DNA from chorionic villi. METHODS: Chorionic villus sampling under transvaginal sonography at 12 weeks of gestation from a woman at risk for a child in a EPPK-affected family was perfomed. Polymerase chain reaction amplification of specific allele (PASA) assay was carried out for the detection of mutation(R162W in keratin 9 [K9] gene) previously identified in this family. Direct DNA sequencing analysis of K9 gene was accomplished to confirm the mutation. RESULTS: We had found the point mutation, R162W of K9 gene, in affected family members and confirmed by PASA assay. Affected family members were shown to have PCR products reactive with both the mutant and wildtype specific primers. Because we could not find any expected products after PASA assay with the primers la(+)/KSmt(-) of the fetal DNA, we predicted that the fetus did not inherited the mutant allele and that the fetus could be unaffected. After PASA assay, we analyzed DNA sequences of two family members to confirm the mutation. A C-to-T substitution at bp 545 was detected in the father, instead the fetus did not have any mutant band at that base pair. CONCLUSION: The PASA assay and direct DNA sequencing analysis of K9 gene through chorionic villi sampling and extraction of genomic DNA had validity to early prenatal diagnosis whether fetus was affected in EPPK or not.