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J Groden

Publications and source records attributed to J Groden.

53 records · Page 3Linked to original sources
PubMed1993

A rapid screening method to detect nonsense and frameshift mutations: identification of disease-causing APC alleles.

A functional screen for nonsense and frameshift mutations has been devised that allows genes of interest to be scanned in segments. This assay is based on the cloning of these segments in-frame with a colorimetric marker gene (lacZ) followed by screening for the level of functional activity from the marker polypeptide (beta-galactosidase). Individuals at risk for any one of a number of genetic diseases, in particular familial adenomatous polyposis coli (APC), can be quickly screened for chain-terminating mutations introduced by stops and frameshifts. At present, scanning of the APC gene for mutation requires significant effort because it is a large gene and most APC mutations are unique. Therefore, this assay offers a powerful option for the diagnosis of this and other genetic diseases, as well as great potential for the development of a similar rapid screen to detect APC mutations in colorectal adenomas and carcinomas.

Alleles↗
PubMed1993

Identical APC exon 15 mutations result in a variable phenotype in familial adenomatous polyposis.

Germ-line mutations in the adenomatous polyposis coli (APC) gene result in familial adenomatous polyposis coli (APC), an inherited syndrome that predisposes affected individuals to early onset of colorectal cancer. Somatic APC mutations also have been detected in sporadic colon tumors. We have used single strand conformational polymorphism (SSCP) analysis to scan a region of the APC gene that frequently is mutated in both APC and sporadic colorectal cancer. Four truncating mutations were found between codons 1060 and 1327 in 17 of 68 unrelated APC individuals. Fourteen of these persons carried either of two previously described five-nucleotide deletions which represent about 20% of APC mutations in these pedigrees. Patients with mutations in this region of exon 15 develop a classic APC colonic phenotype with multiple, diffuse adenomas developing by the second or third decade. However, the density of adenomas and the extracolonic disease manifestations associated with this syndrome are variable among individuals with identical APC mutations.

Adenomatous Polyposis Coli↗
PubMed1993

Mutational analysis of patients with adenomatous polyposis: identical inactivating mutations in unrelated individuals.

Samples of constitutional DNA from 60 unrelated patients with adenomatous polyposis coli (APC) were examined for mutations in the APC gene. Five inactivating mutations were observed among 12 individuals with APC; all were different from the six inactivating mutations previously reported in this panel of patients. The newly discovered mutations included single-nucleotide substitutions leading to stop codons and small deletions leading to frameshifts. Two of the mutations were observed in multiple APC families and in sporadic cases of APC; allele-specific PCR primers were designed for detecting mutations at these common sites. No missense mutations that segregated with the disease were found.

Adenomatous Polyposis Coli↗
PubMed1993

Germ-line mutations in the first 14 exons of the adenomatous polyposis coli (APC) gene.

The first 14 exons of the APC gene have been screened by the denaturation gradient gel electrophoresis method in 160 unrelated patients with familial adenomatous polyposis coli (APC) syndrome. Four polymorphic variants corresponding to silent mutations not associated with the disease phenotype were observed. Mutations predicted to alter the coding property of the APC gene were observed in 26 patients. All these mutations are expected to lead either to aberrant splicing, to synthesis of a truncated APC protein because of the emergence of a stop codon, or to a change in the translation reading frame. Single-base-pair substitutions were observed on 21 occasions. The most frequent mutation (eight cases) was a C-to-T change which exclusively occurred on the nontranscribed strand within a CG dinucleotide.

Adenomatous Polyposis Coli↗
PubMed1993

Identification of APC gene mutations in Italian adenomatous polyposis coli patients by PCR-SSCP analysis.

The APC gene is a putative human tumor-suppressor gene responsible for adenomatous polyposis coli (APC), an inherited, autosomal dominant predisposition to colon cancer. It is also implicated in the development of sporadic colorectal tumors. The characterization of APC gene mutations in APC patients is clinically important because DNA-based tests can be applied for presymptomatic diagnosis once a specific mutation has been identified in a family. Moreover, the identification of the spectrum of APC gene mutations in patients is of great interest in the study of the biological properties of the APC gene product. We analyzed the entire coding region of the APC gene by the PCR-single-strand conformation polymorphism method in 42 unrelated Italian APC patients. Mutations were found in 12 cases. These consist of small (5-14 bp) base-pair deletions leading to frameshifts; all are localized within exon 15. Two of these deletions, a 5-bp deletion at position 3183-3187 and a 5-bp deletion at position 3926-3930, are present in 3/42 and 7/42 cases of our series, respectively, indicating the presence of mutational hot spots at these two sites.

Adenomatous Polyposis Coli↗
PubMed1992

Bloom's syndrome. XVIII. Hypermutability at a tandem-repeat locus.

D1Z2 is a highly polymorphic DNA locus composed of a tandem of repetitive units. Its molecular constitution has been examined in 61 clonal cell lines selected at random from two lymphoblastoid cell lines (LCLs), each of which had been proliferating in vitro for several hundred days. Thirty-three of the cells were selected from an LCL derived from the blood of a person with Bloom's syndrome (BS), and the others from a normal person. A total of 20 distinctive band alterations in D1Z2 were observed, all in BS cells: appearance of a novel band(s); disappearance of a band(s), or alterations in the intensity of a band(s). Unequal sister-chromatid exchange giving rise to intra-locus mutation is considered the most plausible explanation for the accumulation of the changes detected.

Base Sequence↗
PubMed1991

Identification and characterization of the familial adenomatous polyposis coli gene.

DNA from 61 unrelated patients with adenomatous polyposis coli (APC) was examined for mutations in three genes (DP1, SRP19, and DP2.5) located within a 100 kb region deleted in two of the patients. The intron-exon boundary sequences were defined for each of these genes, and single-strand conformation polymorphism analysis of exons from DP2.5 identified four mutations specific to APC patients. Each of two aberrant alleles contained a base substitution changing an amino acid to a stop codon in the predicted peptide; the other mutations were small deletions leading to frameshifts. Analysis of DNA from parents of one of these patients showed that his 2 bp deletion is a new mutation; furthermore, the mutation was transmitted to two of his children. These data have established that DP2.5 is the APC gene.

Adenomatous Polyposis Coli↗
PubMed1991

Identification of deletion mutations and three new genes at the familial polyposis locus.

Small (100-260 kb), nested deletions were characterized in DNA from two unrelated patients with familial adenomatous polyposis coli (APC). Three candidate genes located within the deleted region were ascertained and a previous candidate gene, MCC, was shown to be located outside the deleted region. One of the new genes contained sequence identical to SRP19, the gene coding for the 19 kd component of the ribosomal signal recognition particle. The second, provisionally designated DP1 (deleted in polyposis 1), was found to be transcribed in the same orientation as MCC. Two other cDNAs, DP2 and DP3, were found to overlap, forming a single gene, DP2.5, that is transcribed in the same orientation as SRP19.

Adenomatous Polyposis Coli↗
PubMed1990

Molecular evidence that homologous recombination occurs in proliferating human somatic cells.

A strategy has been developed to detect and characterize certain heritable genomic alterations that occur as cells proliferate in vitro. Multiple subclones of cells were isolated from two clonal lymphoblastoid cell lines--one from a boy with Bloom's syndrome (BS), a cancer-predisposing condition known to feature excessive somatic mutation, the other from a normal man. The DNAs from the cell lines were hybridized to a panel of probes that can detect restriction fragment length polymorphisms, and the patterns of polymorphism in the primary clones were compared with that in each of the secondary clones. In one of the BS secondary clones three loci, positioned distally on the long arm of chromosome 3 and that are heterozygous in the donor and all other cell lines derived from the primary clone, had lost heterozygosity and apparently had become homozygous; in contrast, heterozygous loci more proximal on 3q had retained their heterozygosity, as had those on 3p. Taking into account the pattern of chromosome instability uniquely characteristic of BS, the most plausible explanation for the alterations in the altered clone is that somatic recombination had occurred in vitro, via homologous chromatid interchange. Such spontaneous recombinational events in nonneoplastic, nonmutagenized cells may contribute to the high cancer incidence in BS and, by analogy, to cancer that arises in the general population.

Cell Division↗
PubMed1988

Bilateral keratitis as a manifestation of Lyme disease.

An 11-year-old girl developed bilateral keratitis, which we believe was a manifestation of Lyme disease. She had had several attacks of Lyme arthritis and was twice treated with parenteral penicillin. The keratitis developed five years after the initial episode of Lyme arthritis at a time when there were no other manifestations of Lyme disease. It cleared completely in both eyes after topical corticosteroid therapy.

Child↗
PubMed1988

Procedures to increase social interaction among adolescents with autism: a multiple baseline analysis.

Isolate behavior, impaired social relationships and lack of conversational skills are behaviors which characterize persons described as autistic. These deficits interfere with their effective integration into school and social environments. This study of three subjects investigates the use of imagery procedures, specifically, covert reinforcement, to increase peer verbal initiations in adolescents who are labeled "autistic" and concomitantly looks at the demand characteristics of therapist "request". A multiple baseline analysis was used to assess the effects of individual training sessions on peer verbal initiations. The results demonstrate that verbal initiations can be changed in socially deficient adolescents labeled "autistic".

Adolescent↗
PubMed1987

Effects of fenfluramine on the behavior of autistic individuals.

The present report, part of a national, multicenter study to investigate the effects of fenfluramine on autistic behavior, describes findings on four autistic children ranging in age from 7 to 20 years. Additional performance and parental observation measures apart from those of the multicenter study are included. Results of this study which indicated no significant side effects, a reduction in some deviant behaviors and an improvement in activity level/attention span, provide support for earlier reports. The possibility that fenfluramine's apparently positive effects might be to simply reduce inappropriate behaviors via lethargy was examined and not supported.

Adolescent↗
PubMed1983

Bloom's syndrome cells have an abnormal serum growth response.

Certain growth responses of Bloom's syndrome (BS) dermal fibroblasts have been compared to those of normal human fibroblasts. By applying the principles of Michaelis-Menton kinetics to clonal dose-response data, serum and epidermal growth factor (EGF) requirements of the two cell types were found to be similar. However, the maximal clonal growth rate of BS cells was significantly lower than that of their normal counterparts. Although specific EGF binding by BS cells was marginally higher than in normal cells, EGF's growth-promoting activity was only half of that seen in normal cells. These observations indicate that the abnormally low growth rate of BS cells is not attributable to excessive requirements for serum-derived growth factors and suggest instead that the genetic defect in some way impairs the cells' ability to respond fully to growth stimulation.

Adult↗
PubMedDate not supplied

Different expressivity of two adjacent mutations of the APC gene.

AIMS AND BACKGROUND: The phenotypic expression of different APC mutations in familial adenomatous polyposis (FAP) is variable: two to three variants of the disease have been defined based on the severity of colonic manifestations. Age of onset and number of polypectomies per person-year of post-surgical follow-up were compared in two FAP families with very close mutation sites in the APC gene, in order to ascertain mutation-specific variation of expressivity. FAMILIES AND APC MUTATIONS: Family A (5 patients) carried a newly characterized mutation, a four bp deletion at codon 843. Family B (5 patients) carried a previously identified mutation at codon 835. RESULTS: Mean age of onset was 49.7 years in family A and 30.5 years in family B; number of polypectomies per person-year of follow-up was 1.05 for family A and 10.1 for family B (P < 0.001). CONCLUSIONS: There is significant variation of expressivity (allelic heterogeneity) in FAP between two mutations separated by only eight codons, located at the 5' extremity of APC gene exon 15.

Adenomatous Polyposis Coli↗