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Biomedical subjects

G Tariverdian

Publications and source records attributed to G Tariverdian.

At least 37 records · Page 2Linked to original sources
PubMed1993

Molecular analysis of mutations in the gene FMR-1 segregating in fragile X families.

Molecular genetic analysis of the transmission of mutations in 73 families with fragile X (one of the largest samples evaluated so far) has confirmed previous hypotheses that the fragile X syndrome results from two consecutive mutational steps, designated "premutation" and "full fragile X mutation". These mutations give rise to expansions of restriction fragments, most probably by amplification of the FMR-1 CGG repeat. Premutations are identified by small expansions that apparently have no effect on either the clinical or the cellular phenotype. Full mutations are reflected by large expansions and hypermethylation of the expanded gene region. All males showing large expansions were affected. Individuals with full mutations also expressed the fragile X, with only one exception. An affected "mosaic" male, showing a predominance of premutated fragments in his leukocytes, was shown to be fragile-X-negative on different occasions. About 50% of heterozygotes with full mutations were reported by clinicians to be mentally retarded. Conversion of the premutation to the full mutation may occur at oogenesis, as previously suggested, or after formation of a zygote at an early transitional stage in development when the CGG repeat behaves as a mitotically unstable element on maternally derived/imprinted X chromosomes carrying a premutation of sufficient repeat length.

Alternative Splicing↗
PubMed1991

Tapetoretinal degeneration in brothers with apparent Cohen syndrome: nosology with Mirhosseini-Holmes-Walton syndrome.

We report on 2 brothers with marked eye anomalies, documented with histopathological studies, and several other findings fitting the diagnosis of both the Cohen and the Mirhosseini-Holmes-Walton syndromes. In accordance with Norio and Raitta (Norio R, Raitta C (1986): Am J Med Genet 25:397-398) we come to the conclusion that these 2 syndromes constitute one clinical but possibly heterogeneous entity.

Abnormalities, Multiple↗
PubMed1990

Follow-up of monozygotic twins concordant for the Rett syndrome.

The clinical features and follow-up of monozygotic twins with the Rett syndrome (RS) are described. The twins are almost concordant in all clinical signs. This identity indicates a genetic cause of RS. A clinical follow-up confirmed the diagnosis.

Child, Preschool↗
PubMed1990

[Early amniocentesis].

Preliminary clinical experience with early amniocentesis is reported. Fifty-two amniocenteses were performed before the end of the 14th week following the last menstrual period. Cytogenetic and biochemical analyses (AFP, AChE) were performed. Increasing experience with amniotic fluid samples containing small-cell populations and the use of combined culture media improved the poor initial results to a 100% level, thus enabling the use of this technique for diagnostic purposes. The sampling technique and the post-procedural evolution of twelve amniocenteses in pregnant women, whose pregnancy is to be continued, are presented. The possibility of performing amniocentesis in early pregnancy is discussed with reference to anatomical aspects (amniotic and chorionic cavity).

Acetylcholinesterase↗
PubMed1989

Acrorenal syndrome in an adult--presentation with proteinuria, hypertension, and glomerular lesions.

Acrorenal syndrome is characterized by central longitudinal axis defects of the limbs, ie, split hand and/or foot. Associated renal lesions described so far comprise agenesis, bilateral hypoplasia (originally diagnosed as oligomeganephronia), and duplication abnormalities. The case of a 29-year-old patient with split hand resulting from bilateral aplasia of the third phalanges associated with dysplasia of the third and fourth metacarpals is reported. In addition, the following lesions were noted: hypoplasia of the middle phalanx of the fifth toe, arched palate, pectus excavatum, hypoplastic mammilae, scoliosis, and congenital hip dislocation. The patient presented with hypertension, modest reduction of glomerular filtration, proteinuria, microhematuria, cylindruria, and moderate harmonic hypoplasia of the right kidney on angiography. Glomeruli had no immune deposits on immunohistology. Light microscopy showed widening of the mesangial axis, focal segmental glomerular sclerosis, and renal interstitial fibrosis with occasional foam cells. This case shows that the spectrum of renal abnormalities in the acrorenal syndrome is wider than previously noted.

Abnormalities, Multiple↗
PubMed1988

The secretor locus as a marker for prenatal prediction of myotonic dystrophy (DM).

To verify the reliability of secretor status for prenatal diagnosis of myotonic dystrophy (DM), 179 amniotic fluid samples were compared with saliva or urine samples of the infants by hemagglutination inhibition. While no discrepancies were observed, problems could arise with intermediate results. Additionally, secretor typing is only informative in 8.4% of patients.

ABO Blood-Group System↗
PubMed1987

A monozygotic twin pair with Rett syndrome.

A five-year-old, monozygotic, Turkish female twin pair with Rett syndrome is described. The twins are almost completely concordant in all clinical signs. This observation suggests a genetic cause of Rett syndrome.

Child, Preschool↗
PubMed1987

Prenatal enzymatic diagnosis and exclusion of Krabbe's disease (globoid-cell leukodystrophy) using chorionic villi in five risk pregnancies.

Galactosyl ceramide beta-galactosidase activity was determined in chorionic villi (CV) samples obtained between the 9th and 11th weeks of gestation from 5 women with pregnancies at risk for Krabbe's disease (globoid-cell leukodystrophy, KD). These enzyme activities were compared with those in controls, as well as with those in cultured amniotic fluid cells (AFC) from one of the five at-risk pregnancies and from 29 KD-risk pregnancies studied previously. The results of these CV enzyme analyses were such that one case of fetal KD was clearly diagnosable, one fetal genotype heterozygous for KD was presumed, and three normal fetal genotypes were suggested. The use of both uncultured and cultered CV can be recommended for prenatal KD testing, but AFC may continue to play an important role, too. Of the 58 prenatal KD tests we have evaluated since 1974, a positive diagnosis of Krabbe's disease was made (and confirmed after termination of pregnancy when feasible) in 23 which is significantly more than 25% of 58.

Adult↗
PubMed1987

[Transabdominal chorionic biopsy: indications and timing of the procedure].

The article reports on the introduction of transabdominal chorionic biopsy in the Gynaecological Hospital of Ludwigshafen in cooperation with the Department of Human Genetics at the University of Heidelberg. After completion of a pilot study 15 diagnostic transabdominal chorionic biopsies were performed between the 15th and 23rd pregnancy week. Sampling was successful in all cases; the median estimated weight of the biopsied samples was 35 mg. Cytogenic, biochemical and molecular-genetic examinations were conducted. No complications were seen except for one subserous haematoma. Indications and time of performance are discussed. The transabdominal chorionic biopsy is easier to conduct in the 2nd trimenon than during the first, and can therefore be considered to be a favorable "entry" into the technique. Shifting the biopsy to an earlier date, namely, into the first trimenon, can be aimed at as the familiarity with the technique increases. The obvious advantages of transabdominal removal of villi compared with the transcervical method lead us to expect that in course of the time the transcervical method will be replaced by the transabdominal one. No indication for invasive prenatal diagnosis should be implied without previous detailed genetic counselling.

Adult↗
PubMed1982

Nonspecific X-linked mental retardation--a review.

Mental retardation, in particular the "X-linked" type, has interested geneticists for many years. An increasing number of affected families have been to genetic counselling centres, and an effort is being made to find clinical and cytogenetic methods so a reliable diagnosis can be made. This would enable the detection of carriers and the opportunity to offer prenatal diagnosis. Many questions remain regarding X-linked mental retardation, its causes, diagnosis, and prevention. In this article we try to give an overview about the status of our present knowledge and the questions to be answered in the future.

Chromosome Fragility↗