Assuntos
Códon sem Sentido , Ictiose Ligada ao Cromossomo X/genética , Esteril-Sulfatase/genética , Criança , Análise Mutacional de DNA , Bases de Dados de Proteínas , Predisposição Genética para Doença , Hereditariedade , Humanos , Ictiose Ligada ao Cromossomo X/diagnóstico , Ictiose Ligada ao Cromossomo X/enzimologia , Masculino , Modelos Moleculares , Linhagem , Fenótipo , Conformação Proteica , Esteril-Sulfatase/química , Esteril-Sulfatase/metabolismo , Relação Estrutura-AtividadeRESUMO
A 70-year-old male presented with very large, thick, tightly adherent, dark-brown scales on the front of his lower extremities. His face, neck, back, abdomen, upper extremities, flexural areas, palms and soles as well as hair and nails were not involved. Family history was negative for similar lesions. Otherwise, the patient had a normal development. Onset of symptoms occurred during childhood with scales on lower extremities with no more additional features. Treatment included emollients exclusively with partial and temporary remission of cutaneous lesions. Recently, the patient had not received topical or systemic medical treatment. Laboratory investigations were within normal limits. The patient had undetectable levels of STS activity when compared with normal control (0.00 pmol mg(-1) protein h(-1)) which confirmed the diagnosis of X-linked ichthyosis (XLI) . PCR analysis showed deletion of the STS gene, markers DXS1139 and DXF22S1and the 5' end of the VCX3A gene. The patient had scales present on lower extremities only with no medical treatment that corresponded to an unusual clinical manifestation of XLI. Clinical manifestations of XLI are due to a great variety of environmental, genetic and individual factors that should be considered in XLI diagnosis.
Assuntos
Deleção de Genes , Ictiose Ligada ao Cromossomo X/genética , Ictiose Ligada ao Cromossomo X/patologia , Pele/patologia , Esteril-Sulfatase/genética , Idoso , Saúde da Família , Humanos , Perna (Membro) , Masculino , Índice de Gravidade de DoençaRESUMO
BACKGROUND: Steroid sulphatase (STS) deficiency has been described in a diversity of ethnic populations. The phenotype of STS deficiency, X-linked ichthyosis (XLI), is a genodermatosis characterized by dark scaly skin. About 90% of patients with XLI have complete deletion of the entire STS gene and flanking sequences. The variable number tandem repeats, on either side of the STS gene, appear to play an important role in these interstitial deletions due to nonallelic homologous recombination (NAHR). It is difficult to establish if this NAHR occurs between two chromosomes, between sister chromatids or between the same chromatid. OBJECTIVES: To identify the parental origin of the affected X-chromosome in seven unrelated sporadic cases of XLI. METHODS: Amplification of the regions from DXS89 to DXS1134 (telomeric-centromeric) including the 5' and 3' ends of the STS gene was performed through polymerase chain reaction. GeneScan analysis was performed using the DXS987, DXS8051 and DXS1060 markers located on the short arm of the X-chromosome. Fluorescence in situ hybridization analysis was performed with a digoxigenin-labelled cDNA STS probe. RESULTS: STS gene deletion in patients with XLI involved the sequences DXS1139 and DXF22S1. In five families segregation analysis showed paternal transmission of the affected X-chromosome in the XLI carrier. It was not possible to determine the parental origin of the affected X-chromosome in two families. CONCLUSIONS: These data strongly suggest that STS gene deletion occurred in the male meiosis probably due to an intrachromosomal event, recombination between S232 sequences on the same DNA molecule, or during the process of DNA replication.
Assuntos
Cromossomos Humanos X , Doenças Genéticas Ligadas ao Cromossomo X/genética , Ligação Genética/genética , Ictiose Ligada ao Cromossomo X/genética , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Feminino , Deleção de Genes , Humanos , Masculino , Recombinação GenéticaRESUMO
BACKGROUND: X-linked ichthyosis (XLI), an inborn error of metabolism, is due to steroid sulphatase (STS) deficiency. Most patients with XLI harbour complete deletion of the STS gene and flanking sequences. The presence of low copy number repeats on either side of the STS gene seems to have a major role in the high frequency of these deletions. Some patients with XLI with terminal deletions of Xp22.3 involving marker DXS1139 and the STS gene show mental retardation (MR); VCX3A is the only gene located on this critical region. OBJECTIVES: To analyse the VCX3A, VCX, VCX2 and VCX3B genes in 80 unrelated Mexican patients with XLI with normal intelligence. METHODS: STS activity was measured in the leucocytes using 7-[3H]-dehydroepiandrosterone sulphate as a substrate. Amplification of the regions from telomeric DXS89 to centromeric DXS1134 including both extremes of the STS and the VCX3A, VCX, VCX2 and VCX3B genes was performed using polymerase chain reaction. RESULTS: No STS activity was detected in the patients with XLI (0.00 pmol mg(-1) protein h(-1)). We observed two different deletion patterns: the first group included 62 patients with deletion of VCX3A and VCX genes. The second group included 18 patients with breakpoints at several regions on either side of the STS gene not including the VCX3A gene. CONCLUSIONS: These data indicate that more complex mechanisms, apart from possible VCX3A gene participation, are occurring in the genesis of MR in XLI, at least in the sample of Mexican patients analysed.
Assuntos
Ictiose Ligada ao Cromossomo X , Ictiose Ligada ao Cromossomo X/genética , Deficiência Intelectual/genética , Proteínas Nucleares/genética , Deleção de Genes , Humanos , Ictiose Ligada ao Cromossomo X/enzimologia , Masculino , México/etnologia , Reação em Cadeia da Polimerase/métodos , Resultado do TratamentoRESUMO
La ictiosis ligada al cromosoma X es una genodermatosis poco frecuente que afecta a varones a partir de las 2 semanas de vida y se caracteriza por xerodermia, hiperqueratosis, descamación y, en algunos casos, manifestaciones extracutáneas como criptorquidia y opacidad de la córnea. La enfermedad es de evolución crónica y experimenta mejoría parcial en época estival. La deleción total o parcial de la enzima sulfatasa esteroidea es la causa de las manifestaciones clínicas. Presentamos tres pacientes con ictiosis ligada al cromosoma X, a quienes se les realizaron interconsultas con los servicio de Oftalmología y Pediatría. Se encuentran actualmente en tratamiento con emolientes...
Assuntos
Humanos , Masculino , Criança , Doenças Genéticas Ligadas ao Cromossomo X/genética , Esteril-Sulfatase/genética , Ictiose Ligada ao Cromossomo X/genética , Diagnóstico Diferencial , Pele/patologiaRESUMO
The association of recessive X-linked ichthyosis (RXLI) and hypertrophic pyloric stenosis (HPS) has been considered to be due to a probable contiguous gene defect. However, there are several reports of patients with large deletions on both sides of the steroid sulphatase gene (responsible for RXL1) that show no signs of HPS. We report the third pedigree wherein RXL1 was associated with HPS. Apart from the proband, both diseases showed themselves as independent events in the family tree with ichthyosis present in two other individuals and HPS in three other relatives. We calculated the probability that both diseases occurred simultaneously in the index case as a chance occurrence as 1 : 40 (using the Independence principle of probability). We conclude that in our pedigree it is likely that these two rare diseases show an accidental and not a true genetic association.
Assuntos
Ictiose Ligada ao Cromossomo X/genética , Estenose Pilórica/genética , Criança , Genes Recessivos/genética , Humanos , Hipertrofia , Ictiose Ligada ao Cromossomo X/complicações , Masculino , Linhagem , Probabilidade , Estenose Pilórica/complicaçõesRESUMO
X-linked ichthyosis is an inherited disorder due to steroid sulfatase deficiency. It is clinically characterized by dark, adhesive, and regular scales of the skin. Most X-linked ichthyosis patients present large deletions of the STS gene and flanking markers; a minority show a point mutation or partial deletion of the STS gene. In this study we analyzed the STS gene in a family with simultaneous occurrence of X-linked ichthyosis and ichthyosis vulgaris. X-linked ichthyosis diagnosis was confirmed through steroid sulfatase assay in leukocytes using 7-[3H]-dehydroepiandrosterone sulfate as a substrate. Exons 1, 2, 5, and 6-10, and the 5' flanking markers DXS1130, DXS1139, and DXS996 of the STS gene were analyzed by polymerase chain reaction. X-linked ichthyosis patients of the family (n = 4 males) had undetectable levels of STS activity (0.00 pmol per mg protein per h). The DNA analysis showed that only exons 6-10 and the 5' flanking markers of the STS gene were present. We report the first partial deletion of the STS gene spanning exons 1-5 in X-linked ichthyosis patients.
Assuntos
Arilsulfatases/genética , Éxons/genética , Deleção de Genes , Ictiose Ligada ao Cromossomo X/genética , Humanos , Ictiose Vulgar/complicações , Ictiose Ligada ao Cromossomo X/complicações , Masculino , Esteril-SulfataseRESUMO
BACKGROUND: X-linked ichthyosis (XLI) is an inherited disorder due to steroid sulfatase deficiency (STS). Most XLI patients (>90%) have complete deletion of the STS gene and flanking sequences. The presence of low copy number repeats (G1.3 and CRI-S232) on either side of the STS gene seems to play a role in the high frequency of these interstitial deletions. In the present study, we analyzed 80 Mexican patients with XLI and complete deletion of the STS gene. MATERIALS AND METHODS: STS activity was measured in the leukocytes using 7-[(3)H]-dehydroepiandrosterone sulfate as a substrate. Amplification of the regions telomeric-DXS89, DXS996, DXS1139, DXS1130, 5' STS, 3' STS, DXS1131, DXS1133, DXS237, DXS1132, DXF22S1, DXS278, DXS1134-centromeric was performed through PCR. RESULTS: No STS activity was detected in the XLI patients (0.00 pmoles/mg protein/h). We observed 3 different patterns of deletion. The first two groups included 25 and 32 patients, respectively, in which homologous sequences were involved. These subjects showed the 5' STS deletion at the sequence DXS1139, corresponding to the probe CRI-S232A2. The group of 32 patients presented the 3' STS rupture site at the sequence DXF22S1 (probe G1.3) and the remaining 25 patients had the 3' STS breakpoint at the sequence DXS278 (probe CRI-S232B2). The third group included 23 patients with the breakpoints at several regions on either side of the STS gene. No implication of the homologous sequences were observed in this group. CONCLUSION: These data indicate that more complex mechanisms, apart from homologous recombination, are occurring in the genesis of the breakpoints of the STS gene of XLI Mexican patients.
Assuntos
Arilsulfatases/genética , Deleção de Genes , Ictiose Ligada ao Cromossomo X/genética , Arilsulfatases/deficiência , Humanos , Ictiose Ligada ao Cromossomo X/enzimologia , México , Esteril-SulfataseRESUMO
X-linked ichthyosis is an inherited disease due to steroid sulfatase deficiency. Onset is at birth or early after birth with dark, regular, and adherent scales of skin. Approximately 85%-90% of X-linked ichthyosis patients have large deletions of the STS gene and flanking sequences. Three patients have been identified with partial deletions of the gene. Two deletions have been found at the 3' extreme and the other one implicating exons 2-5. This study describes a novel partial deletion of the STS gene in an X-linked ichthyosis patient. The subject was classified through steroid sulfatase assay in leukocytes using 7-[3H]-dehydroepiandrosterone sulfate as a substrate. Exons 1, 2, 5, and 7-10, and 3' flanking sequences DXS1131, DXS1133, DXS237, DXS1132, DXF22S1, and DXS278 of the STS gene were analyzed through polymerase chain reaction. The DNA analysis showed that exon 1 and 3' flanking sequences from DXS237 to DXS278 were present. In this study we report the fourth partial deletion of the STS gene and the first spanning exons 2-10 in X-linked ichthyosis patients.