Implementation of high-resolution melting analysis of the porcupine (PORCN) gene for molecular diagnosis of focal dermal hypoplasia: Identification of a novel mutation.

BACKGROUND: Focal dermal hypoplasia (FDH) is rare X-linked dominant disease characterized by atrophy and linear pigmentation of the skin, split hand/foot deformities and ocular anomalies. FDH is caused by mutations of the Porcupine (PORCN) gene, which encodes an enzyme that catalyzes the palmitoylation of Wnt ligands required for their secretion. High resolution melting analysis (HRM) is a technique that allows rapid, labor-efficient, low-cost detection of genomic variants. In the present study, we report the successful implementation of HRM in the molecular diagnosis of FDH. METHODS: Polymerase chain reaction and HRM assays were designed and optimized for each of the coding exons of the PORCN gene, processing genomic DNA samples form a non-affected control and a patient complying with the FDH diagnostic criteria. The causal mutation was characterized by Sanger sequencing from an amplicon showing a HRM trace suggesting heterozygous variation and was validated using an amplification-refractory mutation system (ARMS) assay. RESULTS: The melting profiles suggested the presence of a variant in the patient within exon 1. Sanger sequencing revealed a previously unknown C to T transition replacing a glutamine codon for a premature stop codon at position 28, which was validated using ARMS. CONCLUSIONS: Next-generation sequencing facilitates the molecular diagnosis of monogenic disorders; however, its cost-benefit ratio is not optimal when a single, small or medium size causal gene is already identified and the clinical diagnostic presumption is strong. Under those conditions, as it is the case for FDH, HRM represents a cost- and labor-effective approach.

Hipoplasia dérmica focal (síndrome de Goltz) / Focal dermal hypoplasia (Goltz syndrome)

Resumen: Introducción: La hipoplasia dérmica focal o síndrome de Goltz es una rara genodermatosis de herencia dominante ligada al X, que afecta al tejido proveniente de las placas del ectodermo y del mesodermo. El cuadro clínico se caracteriza por alteraciones cutáneas, oftálmicas, neurológicas, dentales, ungueales, bucales, de tejidos blandos y esqueléticas. El diagnóstico se realiza por los hallazgos clínicos en un individuo con alteraciones ectodérmicas y malformaciones características en las extremidades. El manejo es multidisciplinario y, al igual que el pronóstico, depende de las alteraciones específicas que presente cada paciente. Caso clínico: Se presenta el caso de un recién nacido de sexo femenino, de 15 días de vida, con zonas de alopecia en piel cabelluda, herniación de tejido celular subcutáneo en varias áreas de todos los segmentos corporales, escotadura en ala nasal, hendidura en encía superior, defecto grave de extremidad superior izquierda con rizomelia (acortamiento de segmento proximal) y aplasia de radio, así como ectrodactilia de miembro pélvico derecho. Todos los hallazgos son compatibles con hipoplasia dérmica focal de acuerdo con los criterios diagnósticos. Conclusiones: Se presenta el caso de una paciente recién nacida con síndrome de Goltz.

Abstract: Background: Focal dermal hypoplasia or Goltz syndrome is a rare X-linked dominant inherited genodermatosis, affecting both the ectodermal and mesodermal tissue. Clinical manifestations include skin abnormalities, defects in eyes, teeth, nails, mouth, soft tissues and skeleton. The diagnosis is based on clinical findings and is suspected in individuals with ectodermal abnormalities and characteristic malformations in the extremities. The management is multidisciplinary and, like the prognosis, depends on the specific alterations that each patient presents. Case report: We report the case of a 15-day-old female newborn with alopecic areas on the scalp, herniation of subcutaneous cellular tissue at the lumbar level, nasal wing notch, severe left superior limb defect with rhizomelia (proximal segment shortening) and radio aplasia, as well as right leg ectrodactyly, areas of atrophy compatible with focal dermal hypoplasia according to diagnostic criteria. Conclusions: We present a case of female newborn patient with Goltz syndrome.

[Focal dermal hypoplasia (Goltz syndrome)]. / Hipoplasia dérmica focal (síndrome de Goltz).

Background: Focal dermal hypoplasia or Goltz syndrome is a rare X-linked dominant inherited genodermatosis, affecting both the ectodermal and mesodermal tissue. Clinical manifestations include skin abnormalities, defects in eyes, teeth, nails, mouth, soft tissues and skeleton. The diagnosis is based on clinical findings and is suspected in individuals with ectodermal abnormalities and characteristic malformations in the extremities. The management is multidisciplinary and, like the prognosis, depends on the specific alterations that each patient presents. Case report: We report the case of a 15-day-old female newborn with alopecic areas on the scalp, herniation of subcutaneous cellular tissue at the lumbar level, nasal wing notch, severe left superior limb defect with rhizomelia (proximal segment shortening) and radio aplasia, as well as right leg ectrodactyly, areas of atrophy compatible with focal dermal hypoplasia according to diagnostic criteria. Conclusions: We present a case of female newborn patient with Goltz syndrome.

Introducción: La hipoplasia dérmica focal o síndrome de Goltz es una rara genodermatosis de herencia dominante ligada al X, que afecta al tejido proveniente de las placas del ectodermo y del mesodermo. El cuadro clínico se caracteriza por alteraciones cutáneas, oftálmicas, neurológicas, dentales, ungueales, bucales, de tejidos blandos y esqueléticas. El diagnóstico se realiza por los hallazgos clínicos en un individuo con alteraciones ectodérmicas y malformaciones características en las extremidades. El manejo es multidisciplinario y, al igual que el pronóstico, depende de las alteraciones específicas que presente cada paciente. Caso clínico: Se presenta el caso de un recién nacido de sexo femenino, de 15 días de vida, con zonas de alopecia en piel cabelluda, herniación de tejido celular subcutáneo en varias áreas de todos los segmentos corporales, escotadura en ala nasal, hendidura en encía superior, defecto grave de extremidad superior izquierda con rizomelia (acortamiento de segmento proximal) y aplasia de radio, así como ectrodactilia de miembro pélvico derecho. Todos los hallazgos son compatibles con hipoplasia dérmica focal de acuerdo con los criterios diagnósticos. Conclusiones: Se presenta el caso de una paciente recién nacida con síndrome de Goltz.

Chromosome 1p36.22p36.21 duplications/triplication causes Setleis syndrome (focal facial dermal dysplasia type III).

Focal facial dermal dysplasias (FFDD) are characterized by congenital bitemporal or preauricular atrophic skin lesions, and either autosomal dominant or autosomal recessive inheritance. Setleis syndrome (SS), FFDD type III, is a severe form of FFDD with the ectodermal lesions plus other striking facial features. Autosomal recessive nonsense and frameshift mutations in TWIST2 have been found to cause SS in some but not all individuals. Here, we report on four unrelated individuals, one with an unclassified FFDD and the other three with classic SS. Chromosomal microarray analyses revealed unique copy number variants of 1p36 in two individuals with duplications at 1p36.22p36.21 and one with a triplication at 1p36.22p36.21. The fourth patient had normal chromosomes by microarray analysis. All four patients had normal TWIST2 exonic sequences. We propose that a dosage effect of one or more of the 30 genes in the 1.3 Mb 1p36.22p36.21 region of overlap is responsible for FFDD/SS manifestations in some individuals, and this mechanism would be inherited as an autosomal dominant trait. In patients with no duplication/triplication of the 1p36.22p36.21 region and no mutations in TWIST2, there are mutation(s) in one of the 30 genes in this region or mutations in other as yet unidentified genes at different locations that may affect the expressions of genes in this region or act independently to cause this developmental disease phenotype.

Setleis syndrome: genetic and clinical findings in a new case with epilepsy.

BACKGROUND: Focal facial dermal dysplasias are a group of inherited ectodermal disorders characterized by congenital bitemporal or periauricular scar-like depressions as well as other facial and nonfacial developmental defects. Four subtypes have been delineated, and mutations in the TWIST2 gene have been identified in type III focal facial dermal dysplasia (Setleis syndrome). PATIENTS: We describe a sporadic patient with the hallmark bitemporal scar-like lesions, severe intellectual disability, and focal epilepsy. RESULTS: The boy has typical features of Setleis syndrome, and he developed focal epilepsy, a previously unreported feature of this syndrome. No mutations in the TWIST2 gene were found, and there were no pathologic copy number abnormalities. CONCLUSIONS: Epilepsy could represent a new manifestation, and the patient described broadens the spectrum of clinical features associated with Setleis syndrome, including central nervous system involvement.

[A novel PORCN gene mutation in a patient with focal dermal hypoplasia].

OBJECTIVE: To detect the mutation of PORCN gene in a patient with focal dermal hypoplasia and study the genotype-phenotype correlation. METHODS: Peripheral blood samples were obtained from the family members and control subjects. PCR was carried out to amplify all the exons and adjacent splice sites of PORCN gene and mutation was detected by bidirectional sequencing. RESULTS: A G149C mutation was found at exon 2 of the PORCN gene in the patient, which caused a change from Alanine to Proline at codon 38 (A38P). The patient presented mild clinical manifestations. CONCLUSION: A new missense mutation (A38P) in the PORCN was detected in the patient, which maybe one of the molecular mechanisms in the pathogenesis of the disease. The relationship between G149C genotype and moderate phenotype might be attributed to the influence of A38P missense mutation towards the corresponding protein, which is different from previous results.

Electronmicroscopic observation of the basement membrane zone in focal dermal hypoplasia.

A 3-month-old boy had reticulated achromic and atrophic skin lesions on the right buttock and thigh, as well as partial syndactyly of the third and fourth toes of the right foot. With hematoxylin and eosin stain, an epidermal defect, abnormally located fat cell lobules, and absence of the upper and midportions of the dermis were observed, conforming to a typical histopathologic picture of focal dermal hypoplasia. Electron microscopic examination of the atrophic site showed loose collagen bundles, collagen fibers with loss of regular bands, abnormal fibroblasts, and disruption of the basement membrane zone. These defects in the basement membrane zone strongly suggest that abnormal formation of type IV collagen is associated with focal dermal hypoplasia, and that this abnormal formation of collagen is correlated with the clinical sign of skin atrophy.

Comunicación de un caso de hipoplasia dérmica focal (síndrome de Goltz) / Focall dermal hypoplasia (Golt's syndrome): report of one case

El síndrome de Goltz, llamado también hipoplasia dérmica focal (HDF), es un raro desorden hereditario que fue reportado primero en mujeres, descubriéndose más tarde que era letal en los varones. Este síndrome se caracteriza por hipoplasia lineal de la dermis y neoformaciones grasas, asociado con efectos oculares, dentales, esqueléticos, neurológicos, en tejidos blandos, en la piel y raramente trastornos cardiacos y renales. Se describe un paciente masculino de trece años de edad, quien es el primer caso presentado dentro de su familia