RESUMEN
The complete spectrum of clinical phenotypes resulting from glucocerebrosidase deficiency continues to evolve. While most patients with Gaucher disease have residual glucocerebrosidase activity, we describe a fetus with severe prenatal lethal type 2 (acute neuronopathic) Gaucher disease lacking glucocerebrosidase activity. This 22-week fetus was the result of a first cousin marriage and had hydrops, external abnormalities, hepatosplenomegaly, and Gaucher cells in several organs. Fetal fibroblast DNA was screened for common Gaucher mutations, none of which was detected. Southern blot analysis using the restriction enzymes SstII and SspI ruled out a fusion gene, deletion, or duplication of either allele, and quantitative studies of SspI digested genomic DNA indicated that both alleles were present. Northern blot analysis of total RNA from fetal fibroblasts demonstrated no detectable transcription, although RT-PCR successfully amplified several exons, suggesting the presence of a very unstable mRNA. Direct PCR sequencing of all exons demonstrated a homozygous frameshift mutation (deletion of a C) on codon 139 in exon 5, thereby introducing a premature termination codon in exon 6. The absence of glucocerebrosidase protein was confirmed by Western analysis. This unique case confirms the essential role of glucocerebrosidase in human development and, like the null allele Gaucher mouse, demonstrates the lethality of a homozygous null mutation. The presence of this novel mutation and the resulting unstable mRNA accounts for the severity of the phenotype observed in this fetus, and contributes to the understanding of genotype/phenotype correlation in Gaucher disease.
Asunto(s)
Muerte Fetal , Enfermedad de Gaucher/enzimología , Eliminación de Gen , Glucosilceramidasa/genética , Homocigoto , Southern Blotting , Western Blotting , Exones , Femenino , Mutación del Sistema de Lectura , Enfermedad de Gaucher/embriología , Enfermedad de Gaucher/genética , Enfermedad de Gaucher/mortalidad , Glucosilceramidasa/metabolismo , Humanos , Masculino , Linaje , Reacción en Cadena de la Polimerasa , EmbarazoRESUMEN
Neurofibromatosis-1 (NF1) is an autosomal dominant disorder with marked variability of expression. Analysis of the NF1 gene (NF1) has detected a variety of mutations without any clear correlation with phenotype. However, deletions which remove all of NF1 have been reported in a small number of patients who have minor facial abnormalities, mental retardation, learning disabilities, and early or excessive burden of cutaneous or plexiform neurofibromas. The purpose of this study was to determine whether these phenotypic traits are associated with whole gene deletions. Out of 406 of our NF1 patients, 70 patients had manifestations previously associated with gene deletions. Thirty-five of these patients from 26 families were available for study. By fluorescence in situ hybridization (FISH) analysis, 4 were found to have deletions of the entire gene, including 2 sporadic cases, 1 familial case, and 1 case where family history could not be verified. In addition, the mother of the familial case was found to be mosaic for the deletion. Our results suggest that although large NF1 deletions occur with relatively high frequency in patients with certain findings, the presence of a deletion cannot be predicted solely on the basis of clinical phenotype.
Asunto(s)
Eliminación de Gen , Neurofibromatosis 1/genética , Proteínas/genética , Anomalías Múltiples , Adolescente , Adulto , Niño , Preescolar , Humanos , Persona de Mediana Edad , Neurofibromatosis 1/patología , Neurofibromina 1 , FenotipoRESUMEN
A study was designed to assess the effects of the sodium salt of N-monochloroglycine (NMG) and sodium hypochlorite on the activity of salivary amylase. Concentrations of each agent were varied to determine the concentration at which the threshold and total inhibition of enzyme would be obtained. The data indicated that NMG at concentrations of 0.10% (w/v) does not affect amylase activity, whereas sodium hypochlorite at concentrations of 0.05% (w/v) totally inhibits salivary amylase activity.