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L Pulkkinen

Publications and source records attributed to L Pulkkinen.

At least 109 records · Page 6Linked to original sources
PubMed1995

Cloning of the beta 3 chain gene (LAMB3) of human laminin 5, a candidate gene in junctional epidermolysis bullosa.

Laminin 5 consists of three polypeptides, alpha 3, beta 3, and gamma 2, encoded by the genes LAMA3, LAMB3, and LAMC2, respectively. In this study, we have elucidated the exon-intron organization of the human LAMB3 gene. Characterization of five overlapping lambda phage DNA clones revealed that the gene was approximately 29 kb in size. Subsequent sequence data revealed that the gene consisted of 23 exons that varied from 64 to 379 bp in size, accounting for the full-length cDNA with an open reading frame of 3516 bp encoding 1172 amino acids. Comparison of the LAMB3 gene structure with the previously characterized LAMB1 gene revealed that LAMB3 was considerably more compact. Knowledge of the exon-intron organization of the LAMB3 gene will facilitate elucidation of mutations in patients with the junctional forms of epidermolysis bullosa, some of which have been associated with mutations in the laminin 5 genes.

Base Sequence↗
PubMed1995

Detection of sequence variants in the gene encoding the beta 3 chain of laminin 5 (LAMB3).

Laminin 5, a candidate gene/protein system for mutations in the junctional forms of epidermolysis bullosa (JEB), consists of three polypeptides encoded by the LAMA3, LAMB3, and LAMC2 genes. In this study, primer pairs for the amplification of the complete cDNA as well as 22 exons of the LAMB3 gene encoding the entire beta 3 chain of laminin 5, were established. The primers for amplification of individual exons from genomic DNA were placed at least 50 bp away from the exon-intron borders in the flanking intronic sequences. For amplification of cDNA generated by RT-PCR, eight primer pairs covering overlapping segments of mRNA were used. The amplified sequences were used to study sequence variations of the LAMB3 gene in patients with JEB and unrelated individuals using heteroduplex analysis. Nine out of 13 JEB patients examined showed heteroduplexes in at least one of the PCR products, indicating the existence of two variable alleles in their DNA. Sequence analyses revealed putative pathogenetic mutations in seven of the JEB patients, while four of the heteroduplexes resulted from polymorphisms, reflecting a single basepair substitution. The results demonstrate that this method is useful in the detection of JEB mutations, as well as polymorphisms in the LAMB3 gene.

Base Sequence↗
PubMed1995

Genetic basis of lethal junctional epidermolysis bullosa in an affected fetus: implications for prenatal diagnosis in one family.

Fetal skin biopsy at 20 weeks' gestation in a woman at risk for a child with the lethal skin-blistering disorder junctional epidermolysis bullosa (Herlitz) confirmed an affected fetus. Genomic DNA from the aborted fetus was examined for mutations in laminin 5, a macromolecule involved in adhesion at the dermal-epidermal junction, and a candidate protein in this condition. Polymerase chain reaction (PCR) amplification of exon 10 and parts of the flanking introns of the gene encoding the beta 3 chain of laminin 5 (LAMB3) and subsequent analysis by agarose gel electrophoresis showed a more slowly migrating band in the affected fetus compared with the normal control. Nucleotide sequencing of the abnormal PCR product revealed a homozygous 77 bp duplication within the exon, resulting in a premature termination codon 250 bp downstream from the 3' end of the duplication. Maternal DNA was heterozygous for the mutant and wild-type alleles. These findings illustrate the genetic basis of the skin disease in this case and also offer the prospects of a simple, rapid, and reliable first-trimester DNA-based prenatal, or even preimplantation, diagnostic test for future pregnancies in this family.

Adult↗
PubMed1995

Accumulation of problems in social functioning in young adulthood: a developmental approach.

Using longitudinal data from a sample of 369 Finnish adolescents, the authors examined whether problems in social functioning in young adulthood were interrelated and accumulated, and analyzed processes that may lead to cumulative problems. The log-linear modeling showed that an unstable career line of men at age 26 was related to poor social relations, a poor financial standing, drinking problems, and criminal arrests; for both sexes, drinking problems and criminal arrests were interrelated. At a personal level, the authors analyzed male patterns of problems in social functioning and pathways resulting in patterns of social functioning. The pathway leading to an unstable career, criminal arrests, and drinking problems among men included aggressiveness at age 8 and problems in school adjustment and in the family at age 14.

Achievement↗
PubMed1995

Integrin beta 4 mutations associated with junctional epidermolysis bullosa with pyloric atresia.

Pyloric atresia associated with junctional epidermolysis bullosa (PA-JEB), is a rare inherited disorder characterized by pyloric stenosis and blistering of the skin as primary manifestations. We demonstrate that in one PA-JEB patient the disease resulted from two distinct mutations in the beta 4 integrin gene alleles. The paternal mutation consists of a one base pair deletion causing a shift in the open reading frame, and a downstream premature termination codon. The maternal mutation occurs in a donor splice site, and results in in-frame exon skipping involving the cytoplasmic domain of the polypeptide. Our results implicate mutations in the beta 4 integrin gene in some forms of PA-JEB.

Alleles↗
PubMed1995

Identification of a homozygous one-basepair deletion in exon 14 of the LAMB3 gene in a patient with Herlitz junctional epidermolysis bullosa and prenatal diagnosis in a family at risk for recurrence.

Herlitz junctional epidermolysis bullosa, a severe epidermal blistering disorder, is inherited in an autosomal recessive manner. It has recently been shown that, in kindreds with junctional epidermolysis bullosa, the disorder results from mutations in the gamma 2 chain of laminin-5, a basement membrane protein synthesized by the basal cells of stratifying squamous epithelia. In this report we describe a mutation identified in the beta 3 chain gene of laminin-5 in a family with Herlitz junctional epidermolysis bullosa. The disease is caused by a homozygous deletion of 1 bp that leads to a frameshift and premature termination codon. The segregation of the mutated allele in the family is consistent with the pathogenic role of the mutation. We also report a direct DNA-based prenatal exclusion of Herlitz junctional epidermolysis bullosa in a pregnancy at risk using a chorionic villus biopsy and allele-specific oligomer hybridization from polymerase chain reaction-amplified genomic DNA.

Base Sequence↗
PubMed1995

Altered laminin 5 expression due to mutations in the gene encoding the beta 3 chain (LAMB3) in generalized atrophic benign epidermolysis bullosa.

The anchoring filament component laminin 5 (kalinin/nicein) is a candidate protein for mutations in some hereditary blistering skin disorders. In this study, laminin 5 expression was assessed in a family with generalized atrophic benign epidermolysis bullosa, a non-lethal variant of the junctional form of epidermolysis bullosa. Immunofluorescence microscopy of the skin basement-membrane zone with a monoclonal antibody (GB3) revealed reduced anti-laminin 5 staining compared to normal controls. The labeling, when examined by immunoelectron microscopy, was present within the lower lamina lucida, immediately below the plane of blister formation. Numerous hemidesmosomes and well-formed anchoring filaments were seen on transmission electron microscopy. Polymerase chain reaction amplification of genomic DNA encoding the beta 3 subunit (LAMB3) of laminin 5, heteroduplex analysis of the polymerase chain reaction products, and nucleotide sequencing of the heteroduplexes revealed two putative mutations within the LAMB3 gene; these consisted of a premature termination codon in exon 3 and a missense mutation in exon 7. Exons 3 and 7 encode part of domain VI of the laminin 5 beta 3 chain short arm. This globular domain of the protein has been postulated to have an important function in the interaction of laminin 5 with other structural components of the basement membrane zone, such as laminin 6 (K-laminin). Thus the mutations delineated in this family may have a critical pathogenetic significance in reducing adhesion between the epidermis and the dermis.

Base Sequence↗
PubMed1995

Identification of a homozygous exon-skipping mutation in the LAMC2 gene in a patient with Herlitz's junctional epidermolysis bullosa.

We describe a family with the Herlitz type of junctional epidermolysis bullosa, in which the disease is associated with a homozygous splice-site mutation in the gamma 2-chain gene (LAMC2) of laminin-5. The mutation consists of a G-to-T substitution resulting in the out-of-frame skipping of exon 7, a frame shift, and premature stop codon accompanied by a severe reduction in the level of mRNA from the mutant allele. The distribution of the wild-type and mutated gamma 2-chain alleles in family members implicates the mutation in the pathology and confirms the haplotypes of the healthy carriers previously determined by genetic linkage analysis. Our results confirm that the lethal Herlitz junctional epidermolysis bullosa phenotype is caused by mutations resulting in an altered synthesis of laminin-5.

Base Sequence↗
PubMed1995

Behavioral precursors to accidents and resulting physical impairment.

The main goal of the study was to determine, within a model of emotional and behavioral regulation, if there are developmental precursors to accidents and resulting physical impairment. Data collected at ages 8 and 14 with 147 males and 142 females using peer nomination and teacher rating were related to the number of types of accidents the subjects had been in and impairment as a result of an accident by the age of 27 when the subjects were interviewed on their health. The results showed that 44% of the men and 14% of the women had been in an accident. Severe effects on health were obtained for 19% of the men and 5% of the women. Accidents and impairment were most frequent among individuals whose behavior had been characterized by low emotional and behavioral control. The most generalized predictor of accidents and impairment was noncompliance in childhood. In adulthood, heavy drinking increased the risk of accidents. Aggression and conduct problems were the most significant precursors to male impairment, although several subgroups of men who were impaired were found. For females, the predictions of accidents and impairment were less accurate than for males.

Accident Proneness↗
PubMed1994

A homozygous nonsense mutation in the beta 3 chain gene of laminin 5 (LAMB3) in Herlitz junctional epidermolysis bullosa.

Herlitz junctional epidermolysis bullosa (H-JEB) is a severe autosomal recessive disorder characterized by blister formation within the dermal-epidermal basement membrane. Based on immunofluorescence analysis recognizing laminin 5 epitopes (previously known as nicein/kalinin), the genes for this lamina lucida protein have been proposed as candidate genes in H-JEB. In this study, we examined the gene encoding the beta 3 polypeptide chain of laminin 5 (LAMB3) by Northern hybridization and RT-PCR analysis of keratinocyte mRNA from a proband in a family with H-JEB. Northern analysis revealed markedly reduced levels of the laminin beta 3 chain mRNA. Amplification of mRNA by RT-PCR, followed by direct nucleotide sequencing, revealed a homozygous C-to-T transition resulting in a premature termination codon (CGA --> TGA) on both alleles. This mutation was verified at the genomic DNA level, and both parents were shown to be heterozygous carriers of the same mutation. This is the first description of a mutation in the laminin beta 3 chain gene (LAMB3) of laminin 5 in an H-JEB patient.

Base Sequence↗
PubMed1994

Fragile-X syndrome in east Finland: molecular approach to genetic and prenatal diagnosis.

Fragile X is the most common inherited form of mental retardation, having an incidence of one in 1,250 males. The fragile X syndrome results from amplification of the CGG repeat found in the fragile X mental retardation-1-gene (FMR-1). This CGG repeat shows length variation in normal individuals and is increased significantly in both carriers and patients. Non-retarded carriers of both sexes can be detected reliably only by direct DNA analysis of the fra(X) mutation. Here we investigate fragile X families using the intragenic probes St.B 12.3 and St.B 12.3 XX (J-L Mandel). Fragile X syndrome could be verified in 51 families of the population of 900,000 in East-Finland during 1989-92. The index cases of the syndrome were found by the help of health care personnel, 463 relatives of these families consented to be tested for the mutation of the FMR-1 gene. Ninety-three relatives with the full mutation and 127 healthy carriers with the premutation of the fragile X syndrome were diagnosed. In addition, 28 decreased males were obligate carriers. During the year 1992 prenatal diagnosis for fragile X was carried out in nine pregnancies. For understanding of the occurrence of fragile X syndrome and for better prevention of this syndrome in next generations, systematic genetic counseling and carrier screening in these families is essential.

Female↗
PubMed1994

Mutations in the gamma 2 chain gene (LAMC2) of kalinin/laminin 5 in the junctional forms of epidermolysis bullosa.

Junctional epidermolysis bullosa (JEB) is an autosomal recessive disorder characterized by blister formation within the dermal-epidermal basement membrane. Genes for the lamina lucida protein, kalinin/laminin 5, have been proposed as candidates for some forms of JEB, based on immunofluorescence analysis recognizing kalinin epitopes. We studied the cDNA of laminin gamma 2 chain for mutations in JEB using heteroduplex analysis. One patient showed a homozygous splice site mutation while another was heterozygous for a deletion-insertion, resulting in a premature termination codon in one allele. Our data implicate mutations in the laminin gamma 2 chain gene (LAMC2) in some forms of JEB.

Base Sequence↗
PubMed1994

Herlitz's junctional epidermolysis bullosa is linked to mutations in the gene (LAMC2) for the gamma 2 subunit of nicein/kalinin (LAMININ-5).

We have linked Herlitz's junctional epidermolysis bullosa (H-JEB) to the gene (LAMC2) encoding the gamma 2 subunit of nicein/kalinin, an isolaminin (laminin-5) expressed by basal keratinocytes. In four H-JEB kindreds, a maximum two-point lod score of 5.33 at theta = 0 was observed between a microsatellite near LAMC2 at 1q25-31 and the disease. In one family, a homozygous point mutation leading to a premature stop codon (CGA to TGA) was identified in exon 3 of the gene. The segregation of the mutated allele implicates the mutation in the pathology of the disorder and corroborates the linkage results.

Base Sequence↗
PubMed1994

Molecular basis of the dystrophic and junctional forms of epidermolysis bullosa: mutations in the type VII collagen and kalinin (laminin 5) genes.

Epidermolysis bullosa (EB) is a group of heritable mechano-bullous skin diseases classified into three major categories, the simplex, junctional, and dystrophic forms, on the basis of the level of tissue separation within the dermal-epidermal basement membrane zone. Approaches of molecular biology have demonstrated that these three different forms of EB result from mutations in distinct genes: the simplex forms are due to mutations in the genes encoding keratins 5 and 14 expressed in basal keratinocytes; the junctional forms are associated with mutations in the kalinin/laminin 5 genes; and the dystrophic forms result from mutations in the type VII collagen gene (COL7A1). In this overview, we summarize our recent discoveries of pathogenic mutations in COL7A1, including premature termination codons that result in the severe, mutilating (Hallopeau-Siemens) type of recessive dystrophic EB and a glycine substitution in the collagenous region resulting in dominant dystrophic EB. Furthermore, we present evidence that implicates mutations in the kalinin/laminin 5 gamma 2 chain gene (LAMC2) in some forms of junctional EB. This information has provided the basis for DNA-based prenatal diagnosis during the first trimester of gestation, and sets the stage for the application of gene therapy to these devastating skin diseases in the future.

Cell Adhesion Molecules↗
PubMed1994

Mutations in the non-helical linker segment L1-2 of keratin 5 in patients with Weber-Cockayne epidermolysis bullosa simplex.

Keratins are the major structural proteins of the epidermis. Analyzing keratin gene sequences, appreciating the switch in keratin gene expression that takes place as epidermal cells commit to terminally differentiate, and elucidating how keratins assemble into 10 nm filaments, have provided the foundation that has led to the discoveries of the genetic bases of two major classes of human skin diseases, epidermolysis bullosa simplex (EBS) and epidermolytic hyperkeratosis (EH). These diseases involve point mutations in either the basal epidermal keratin pair, K5 and K14 (EBS), or the suprabasal pair, K1 and K10 (EH). In severe cases of EBS and EH, mutations are found in the highly conserved ends of the alpha-helical rod domain, regions that, by random mutagenesis, had already been found to be important for 10 nm filament assembly. In order to identify regions of the keratin polypeptides that might be more subtly involved in 10 nm filament assembly and to explore the diversity in mutations within milder cases of these diseases, we have focused on Weber-Cockayne EBS, where mild blistering occurs primarily on the hands and feet in response to mechanical stress. In this report, we show that affected members of two different W-C EBS families have point mutations within 1 residue of each other in the non-helical linker segment of the K5 polypeptide. Genetic linkage analyses, the absence of this mutation in > 150 wild-type alleles and filament assembly studies suggest that these mutations are responsible for the W-C EBS phenotype. These findings provide the best evidence to date that the non-helical linker region in the middle of the keratin polypeptides plays a subtle but significant role in intermediate filament structure and/or intermediate filament cytoskeletal architecture.

Alleles↗
PubMed1994

A prospective study of the precursors to problem drinking in young adulthood.

This study was part of the Jyväskylä Longitudinal Study on Social Development. The subjects (196 males, 173 females) were studied at age 8, 14 and 26. Three components in drinking habits were obtained at age 26: social, problem and controlled drinking. Moderate to severe problem drinking was obtained for 26% of the men and 1% of the women, and mild problem drinking for 23% of the men and 15% of the women. Problem drinking (defined by the CAGE Questionnaire, arrest for alcohol abuse and other indicators of heavy drinking) was directly accounted for by poor school success at age 14 and, for men, by conduct problems and low anxiety. Variables at age 8 that contributed indirectly to adult problem drinking were aggression, low anxiety, low prosociality and poor school success for men, and high anxiety and poor school success for women. Women and men differed in the effect of social anxiety; in men, anxiety was a protective factor against problem drinking; in women, it was a risk factor. Although conduct problems often precede severe problem drinking, other risk factors may exist among sons of alcoholic parents. Parental drinking had a significant threshold effect on male off-springs' drinking: if parental drinking was low, there was less problem drinking among the male offspring than if a mild dependence on alcohol was observed in the parents.

Achievement↗
PubMed1993

Epidermolytic hyperkeratosis (bullous congenital ichthyosiform erythroderma). Genetic linkage to chromosome 12q in the region of the type II keratin gene cluster.

Epidermolytic hyperkeratosis (EHK) is an autosomal dominant genodermatosis characterized by hyperkeratosis and blistering of the skin. Histopathology demonstrates suprabasilar blister formation with aggregation of tonofilaments. In this study, we tested the hypothesis that the EHK phenotype is linked to one of the suprabasilar keratins (KRT10 or KRT1) present in the types I and II keratin gene clusters in chromosomes 17q and 12q, respectively. For this purpose, Southern hybridizations were performed with DNA from a large kindred with EHK, consisting of 11 affected individuals in three generations. Segregation analysis with markers flanking the keratin gene clusters demonstrated linkage (Z = 3.61 at theta = 0) to a locus on 12q, while markers on 17q were excluded. These data implicate KRT1, the type II keratin expressed in suprabasilar keratinocytes, as a candidate gene in this family with EHK.

Blotting, Southern↗