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Biomedical subjects

P Ashton-Prolla

Publications and source records attributed to P Ashton-Prolla.

11 recordsLinked to original sources
PubMed2005

An alternative protocol for DNA extraction from formalin fixed and paraffin wax embedded tissue.

BACKGROUND: DNA extraction from paraffin wax embedded tissue requires special protocols, and most described methods report an amplification success rate of 60-80%. AIMS: To propose a simple and inexpensive protocol consisting of xylene/ethanol dewaxing, followed by a kit based extraction. METHOD: Xylene/ethanol dewaxing was followed by a long rehydration step and a kit based DNA extraction step. RESULTS: This method produced a 100% amplification success rate for fragments of 121 to 227 bp for tamponated formalin fixed paraffin wax embedded tissue. CONCLUSION: This cost effective and non-laborious protocol can successfully extract DNA from tamponated formalin fixed paraffin wax embedded tissue and should facilitate the molecular analysis of a large number of archival specimens in retrospective studies.

DNA, Neoplasm↗
PubMed2000

Fabry disease: twenty-two novel mutations in the alpha-galactosidase A gene and genotype/phenotype correlations in severely and mildly affected hemizygotes and heterozygotes.

BACKGROUND: Fabry disease, an inborn error of glycosphingolipid catabolism, results from mutations in the X-chromosomal gene encoding the lysosomal exoglycosidase, alpha-galactosidase A (alpha-Gal A; EC 3.2.1.22). The nature of the molecular lesions in the alpha-Gal A gene in 36 unrelated families was determined in order to provide precise heterozygote detection, prenatal diagnosis, and to define genotype/phenotype correlations. METHODS: Genomic DNA was isolated from affected males and/or carrier females from 36 unrelated families with Fabry disease. The entire alpha-Gal A coding region and flanking intronic sequences were analyzed by PCR amplification and solid-phase or cycle sequencing. Markers closely linked to the alpha-Gal A gene were analyzed to determine if probands with the same mutations were related. RESULTS: Twenty-two novel mutations were identified including 10 missense (P40L, W95S, S148N, C172R, M187V, N224S, W226R, A230T, D266H, N320Y), three nonsense (Y134X, C142X, W204X in two families), three splice-site defects (IVS2(+1), IVS3(+1), IVS4(+1)) and six small deletions or insertions (26delA in two families, 672ins37, 774delAC, 833insA, 1139delC, 1188insT). Of the remaining 12 families (33.3%), each had a previously identified mutation, eight of which occurred at CpG dinucleotides including R112C (two families), R112H, R227Q, R227X (three families), and R301Q. Haplotype analysis of the mutant alleles that occurred in two or three presumably unrelated families revealed that the families with the rare novel alleles (W204X and 26delA) were probably related, whereas those with mutations involving CpG dinucleotides (R112C and R227X) were not, the latter being consistent with their origins as independent mutational events. Genotype/phenotype correlations revealed that certain mutations previously found in mild variant patients also were found in classic patients. In addition, the genotypes and spectrum of phenotypic severity were determined in five heterozygotes with no family history. CONCLUSIONS: These results illustrate the molecular heterogeneity of the lesions causing Fabry disease and emphasize the fact that CpG dinucleotides constitute important hot spots for mutation in the alpha-Gal A gene. These studies also permit precise heterozygote detection and prenatal diagnosis in these families, and delineate phenotype-genotype correlations in this disease.

Amino Acid Sequence↗
PubMed1999

Fabry disease: comparison of enzymatic, linkage, and mutation analysis for carrier detection in a family with a novel mutation (30delG).

Fabry disease (FD) is an X-linked recessive disorder caused by the deficient activity of the lysosomal enzyme alpha-galactosidase A (alpha-Gal A). Affected males are reliably diagnosed by demonstration of deficient alpha-Gal A activity in plasma or leukocytes. However, identification of female carriers is problematic due to Lyonization, requiring mutation identification and/or linkage studies for accurate carrier detection. Here, we describe a large Brazilian kindred with Fabry disease that permitted comparison of biochemical and molecular diagnostic techniques. Initially, the plasma alpha-Gal A activities were determined in at-risk affected males and potential female carriers; affected males were readily diagnosed, while the females had variable results. To detect carrier females, haplotype analysis using 10 polymorphic markers adjacent to the gene was performed. Subsequently, solid-phase direct sequencing of the alpha-Gal A gene demonstrated a novel single base deletion in exon 1 (30delG). Discrepancies were observed between the enzymatic and molecular diagnoses in two at-risk females. These findings emphasize the need for precise heterozygote diagnosis by mutation and/or haplotype analyses in all families with Fabry disease.

Base Sequence↗
PubMed1999

Non-pseudogene-derived complex acid beta-glucosidase mutations causing mild type 1 and severe type 2 gaucher disease.

Gaucher disease is an autosomal recessive inborn error of glycosphingolipid metabolism caused by the deficient activity of the lysosomal hydrolase, acid beta-glucosidase. Three phenotypically distinct subtypes result from different acid beta-glucosidase mutations encoding enzymes with absent or low activity. A severe neonatal type 2 variant who presented with collodion skin, ichthyosis, and a rapid neurodegenerative course had two novel acid beta-glucosidase alleles: a complex, maternally derived allele, E326K+L444P, and a paternally inherited nonsense mutation, E233X. Because the only other non-pseudogene-derived complex allele, D140H+E326K, also had the E326K lesion and was reported in a mild type 1 patient with a D140H+E326K/K157Q genotype, these complex alleles and their individual mutations were expressed and characterized. Because the E233X mutation expressed no activity and the K157Q allele had approximately 1% normal specific activity based on cross-reacting immunologic material (CRIM SA) in the baculovirus system, the residual activity in both patients was primarily from their complex alleles. In the type 1 patient, the D140H+E326K allele was neuroprotective, encoding an enzyme with a catalytic efficiency similar to that of the N370S enzyme. In contrast, the E326K+L444P allele did not have sufficient activity to protect against the neurologic manifestations and, in combination with the inactive E233X lesion, resulted in the severe neonatal type 2 variant. Thus, characterization of these novel genotypes with non-pseudogene-derived complex mutations provided the pathogenic basis for their diverse phenotypes.

Alleles↗
PubMed1997

Prenatal diagnosis of a familial interchromosomal insertion of Y chromosome heterochromatin.

An apparently unbalanced karyotype containing an abnormal chromosome 11 was identified in a 16-week female fetus by analysis of cultured amniocytes. Fluorescence in situ hybridization (FISH) with a chromosome 11 paint identified the presence of an insertion in band 11q24. Parental karyotyping documented an unbalanced karyotype with the same der(11) chromosome in the phenotypically normal father. CBG-banding and FISH identified the insertion to be Yq12 heterochromatin: 46,XY, der(11)ins(11;Y)(q24;q12q12).ish der(11) (wcp11+,DYZ1+). The same der(11) chromosome was also found in the phenotypically normal paternal grandmother, demonstrating this additional Y chromosomal material did not affect normal female sexual development or fertility. The parents elected to continue the pregnancy and a normal girl was born at term, further confirming that this rare familial variant has no clinical significance. This case illustrates the importance of family studies, appropriate banding, and FISH analyses to accurately characterize apparent chromosomal abnormalities.

Adult↗
PubMed1997

Say syndrome: a new case with cystic renal dysplasia in discordant monozygotic twins.

Say syndrome is a rare condition characterized by cleft palate, short stature, and microcephaly. Abu-Libdeh et al. [1993: Am J Med Genet 45:358-360] described a case with cystic renal dysplasia. We describe monozygotic twins discordant for the syndrome with kidney dysplasia. A postzygotic mutation is proposed as the cause of this autosomal dominant syndrome in this case.

Abnormalities, Multiple↗
PubMed1996

Thalidomide, a current teratogen in South America.

Thalidomide, mainly used for the treatment of leprosy, is a current teratogen in South America, and it is reasonable to assume that at present this situation is affecting many births in underdeveloped countries. Moreover, the potential re-marketing of thalidomide for the treatment of a large variety of diseases may extend the problem to the developed world. When the drug is available, the control of its intake during early pregnancy is very difficult since most pregnancies are unintended. The ongoing occurrence of thalidomide embryopathy cases went undetected by the ECLAMC, due to several factors: (1) low populational coverage through this monitoring system; (2) pre-existence of the teratogen with its effects present in both baseline (expected) and monitored (observed) materials; and (3) lack of a defined phenotype to be monitored. Thus, if thalidomide re-enters the market throughout the world, due to the wide range of new applications, occurrence of phocomelia alone might not be sufficient to detect its effects. By a case-reference approach, the ECLAMC registered 34 thalidomide embryopathy cases born in South America after 1965 whose birthplaces correspond to endemic areas for leprosy. Phocomelia was found in five of eleven fully described cases. Thus, phocomelia alone is neither specific nor sufficient to serve as a suitable phenotype to survey the teratogenic effects of thalidomide. Therefore, a thalidomide-like phenotype, defined as any bilateral upper and/or lower limb reduction defect of the preaxial and/or phocomelia types, should be included in the routine surveillance of birth defects in all programmes.

Abnormalities, Drug-Induced↗
PubMed1996

Maternal hyperphenylalaninaemia as a cause of microcephaly and mental retardation.

We attempted to evaluate the role of maternal hyperphenylalaninaemia (HPA) as an isolated cause of mental retardation and microcephaly in children. This transversal study observed the plasma phenylalanine from mothers of 161 children with mental retardation and/or microcephaly of unknown origin. In this sample, we found two women with previously undiagnosed HPA, a frequency (2/161) higher than expected for our general population (1:12 500) (p < 0.001). We concluded that the plasma phenylalanine levels should be determined during preconceptional evaluation of every woman of reproductive age that already has had a child affected either by mental retardation or microcephaly of unknown cause. It is particularly significant where women currently having their pregnancies have not been screened for phenylketonuria as newborns, as happens in most developing countries.

Adult↗
PubMedDate not supplied

Pregnancy outcome after exposure to misoprostol in Brazil: a prospective, controlled study.

BACKGROUND: Misoprostol, a synthetic prostaglandin E1 analog is labeled for the treatment of gastric and duodenal ulcers. In Brazil, where abortion is not a legal procedure, there is a widespread popular misuse of this drug in abortion attempts. This misuse and the fact that, in many cases the desired pregnancy termination does not occur, raise concerns about fetal safety. Case reports of congenital anomalies after maternal use of misoprostol have been published. The objective of this work was to compare pregnancy outcome following misoprostol exposure with a matched control group. This is the first prospective controlled study on fetal safety after misoprostol use. METHODS: A prospective, observational cohort study with 86 exposed and 86 pair-matched, non-exposed controls. RESULTS: There was no significant difference in the rates of major or minor birth between exposed compared to non-exposed infants (2/67 vs 2/81, major defects; 7/67 vs. 3/81, minor anomalies) There were significantly more miscarriages in the exposed group (17.1% vs. 5.8%; relative risk, 2.97; 95% confidence interval, 1.12 to 7.88). There was no statistical difference in gestational age at delivery, birth weight, sex ratio, rate of prematurity, low birth weight, or rates of cesarean section between groups. CONCLUSIONS: Our study, despite its limited statistical power, does not suggest a potent teratogenic action of misoprostol exposure during pregnancy.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

[Inborn errors of metabolism: practical guidelines for clinical diagnosis in acutely ill children and infants].

The manifestations of Inborn Errors of Metabolism (IEM) with an acute presentation are extremely unspecific, which makes its diagnosis a task of laboratorial interpretation. At the same time, the early diagnosis of many of these IEM allows quite satisfactory therapeutic interventions, followed by favorable clinical evolutions. To make the work of pediatricians and neonatologists easier in the diagnosis and immediate management of these conditions with an acute onset, a flowchart of procedures is suggested. The different steps suggested are justified and complemented by adjacent comments, which are restricted to the more serious and common manifestations of these disorders, like metabolic acidosis, hyperammonemia and hypoglycemia. Finally, the reading of specific and more detailed literature is suggested for the understanding of the different families of specific IEM.

English Abstract↗