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Biomedical subjects

E W Lovrien

Publications and source records attributed to E W Lovrien.

At least 19 recordsLinked to original sources
PubMed1991

CG dinucleotide transitions in the factor IX gene account for about half of the point mutations in hemophilia B patients: a Seattle series.

Hemophilia B is due to multiple molecular defects in the factor IX gene. Over 80% of mutations are single base substitutions. By amplification and direct sequencing, 51 single base substitutions were found in the transcribed sequence of the factor IX genes of patients from 50 distinct families with hemophilia B. These include 30 mutations in 29 families not previously reported by us; of these, 12 are novel, i.e., not previously published in other series. Of the 51 substitutions in our overall series 23 (45%) occurred as C-to-T or G-to-A transitions at 11 sites within CG dinucleotides. It is estimated that CG transitions occur from one to two orders of magnitude more frequently than mutations in nucleotides that are not within a CG pair. More than one family had identical defects for 6 of the CG mutations. At 4 of these sites, most patients had different haplotypes compatible with distinct mutations. Non-CG-type mutations occurred throughout the coding regions with only one mutation in more than one family. The latter included 7 families with a 397 Ile-to-Thr defect that all share a rare haplotype, suggesting a common ancestor.

Amino Acid Sequence↗
PubMed1990

Microphthalmos in the presumed homozygous offspring of a first cousin marriage and linkage analysis of a locus in a family with autosomal dominant cerulean congenital cataracts.

A family with autosomal dominant congenital cataracts was studied to determine clinical variability. A total of 159 relatives was ascertained; 17 affected and 19 normal individuals were evaluated and their blood sampled for inclusion in the linkage analysis. The disease was compatible with normal to mildly decreased visual acuity until adult life in all affected except the product of a consanguineous marriage of affected first cousins who was born with bilateral microphthalmos and dense congenital cataracts, attributed to homozygosity of the cataract gene. There were no extraocular abnormalities; the patient was of normal intelligence. Twenty-three markers were typed, 18 of which were informative. Linkage could be excluded for all 18 markers at short distances.

Cataract↗
PubMed1990

Structural and functional basis of the developmental regulation of human coagulation factor IX gene: factor IX Leyden.

Hemophilia B Leyden is characterized by unusual developmental regulation of factor IX synthesis in affected individuals. One family affected with the hemophilia B Leyden phenotype was found to have a specific single-base mutation (G----A) at nucleotide -6 of the factor IX gene. The mutation site was found in a small region of the 5'-untranslated sequence designated the Leyden-specific region (LS region). This region, approximately 40 base pairs in length, contains the unique mutation sites of all the known factor IX Leyden genes (five families) analyzed to date. This fact strongly suggests that the LS region is directly or indirectly involved in the developmental regulation of factor IX biosynthesis. Base changes at nucleotide -20 as well as at nucleotide -6 and deletions of the 3' half of the LS region reduced expression activity of the factor IX gene to approximately 15-31% that of the normal control, as assessed in a cultured cell (HepG2) expression system. The LS region binds at least two proteins. Androgen significantly increased the transcriptional activities of both mutant and normal factor IX genes in a concentration-dependent manner.

Aging↗
PubMed1979

The 8p- syndrome.

A boy with severe retardation of growth and development, minor dysmorphic features, severe congenital heart disease, and a 46,XY,8p-karyotype is described. The clinical findings of this boy are compared with those of others reported monosomic for a portion of the short arm of chromosome 8. The red cell glutathione reductase (GSR) level is normal in our patient.

Chromosome Deletion↗
PubMed1978

Aicardi's syndrome. Case report, clinical features, and electrophysiologic studies.

Aicardi's syndrome consists of abnormalities of the ocular fundus, myoclonic seizures, mental retardation, and congenital malformations of the brain and vertebral column in females. The pathognomonic chorioretinal lesions were noted on ophthalmologic examination of a 22-month-old girl, observed for 19 months with severe myoclonic seizures and profound mental retardation. Computerized tomography confirmed major malformation of the brain. Roentgenograms showed anterior fusion of two thoracic vertebrae. Electroretinography was normal, but visual evoked responses were abnormal. Only 72 children are known to have this syndrome; no affected siblings have been reported. The absolute sex limitation--all cases have been female--suggests that the disorder is produced by a mutation on one of the X chromosomes, and is nonviable in male conceptuses. These genetic considerations dramatically influence counseling of parents regarding likelihood of occurrence of the syndrome in subsequent offspring.

Abnormalities, Multiple↗
PubMed1977

The fetal trimethadione syndrome: report of an additional family and further delineation of this syndrome.

We describe a family in which seven pregnancies resulted in four infants who died and in three abortions. During these pregnancies the mother took trimethadione (Tridione), as well as other anticonvulsants. Two normal children were born after treatment with all medications were stopped. There have now been 53 reported pregnancies in which the fetuses were exposed to trimethadione or paramethadione; 48 (87%) resulted in fetal loss or a child born with congenital malformations. The most common defects include malformed ears, cleft palate, cardiac defects, urogenital malformations, and skeletal abnormalities. Delayed mental and physical development were also seen. These findings constitute a clinical entity termed the fetal trimethadione syndrome. The malformation rate is believed to be due to the teratogenic effects of trimethadione. Physicians need to be aware of the danger of trimethadione and related drugs during pregnancy and should withhold these medications during this period.

Abnormalities, Drug-Induced↗
PubMed1977

Mannosidosis in three brothers--a review of the literature.

Three brothers with mannosidosis were studied, and their clinical and biochemical manifestations are compared with those of 41 cases in the literature. All three boys have psychomotor and growth retardation, characteristic facies, recurrent respiratory infections, sensorineural deafness, craniosynostosis, protuberant abdomens, and thin limbs. Roentgenographic findings of mild dysostosis multiplex, thick calvaria, abnormally contoured vertebrae, coarse trabeculi and thin cortices are consistent with those of reported cases. The lymphocytes of peripheral blood and bone marrow are vacuolated. Alpha-mannosidase deficiency in leukocytes and cultured skin fibroblasts and glycoproteinuria have been documented. The biochemistry of this glycoproteinosis and the pitfalls in diagnosis, such as improper assay conditions of pH and substrate concentration, are discussed. Extrapolation of in vitro and animal model studies suggest that trace metal therapy may be more effective than attempts at enzyme replacement to treat this hereditary storage disease.

Adolescent↗
PubMed1977

Central nervous system arteriovenous malformations in multiple generations of a family with hereditary hemorrhagic telangiectasia.

Hereditary hemorrhagic telangiectasia is described in four generations of a kinship. The family is unique in that three generations manifest central nervous system vascular disease, which was pathologically confirmed in two generations. Genetic linkage was not identified for 32 genetic markers studied. The literature is reviewed for patients with central nervous system arteriovenous malformations and hereditary hemorrhagic telangiectasia. The pathogenesis of the disease is discussed, and therapeutic modalities are considered.

Adult↗
PubMed1976

Estimating distances from the centromere by means of benign ovarian teratomas in man.

Under the assumption that benign ovarian teratomas in man arise parthenogenically from a germ cell by suppression of the second meiotic division, the distance of a gene from its centromere can be estimated from the observed proportion of heterozygous teratomas collected from heterozygous hosts. The frequency of heterozygous teratomas of heterozygous hosts is equivalent to the frequency of second division segregation at the gene locus which has been used for centromere-related mapping in fungal genetics for more than 40 years. Mapping functions useful for teratoma-based mapping in man are presented.

Chromosome Mapping↗
PubMed1976

Human centromere mapping using teratoma data.

Under the assumption that benign ovarian teratomas arise parthenogenetically from a germ cell by suppression of the second meiotic division, the proportion gamma of heteratomas collected from heterozygous hosts is a measure for the distance between the corresponding gene and its centromere. For proportions gamma less than or equal to 0.3, the mapping function x = gamma/2 applies, where x is the map distance in Morgans.

Cells, Cultured↗