Preimplantation genetic diagnosis of human embryos for Marfan's syndrome.

Purpose: Single-cell nested polymerase chain reaction (PCR) and Ddel endonuclease digestion were used to detect the presence of a Marfan's syndrome mutation in human preimplantation embryos derived from in vitro fertilization (IVF). These procedures were conducted to eliminate the possibility of transmission of the affected allele from the father to his offspring. The mutation on chromosome 15 is transmitted as an autosomal dominant trait, and the chance of having a child affected with the disease is 50%.

Targetting of the gene encoding fibrillin-1 recapitulates the vascular aspect of Marfan syndrome.

Aortic aneurysm and dissection account for about 2% of all deaths in industrialized countries; they are also components of several genetic diseases, including Marfan syndrome (MFS). The vascular phenotype of MFS results from mutations in fibrillin-1 (FBN1), the major constituent of extracellular microfibrils. Microfibrils, either associated with or devoid of elastin, give rise to a variety of extracellular networks in elastic and non-elastic tissues.

Inhibition of fibrillin 1 expression using U1 snRNA as a vehicle for the presentation of antisense targeting sequence.

This study examines whether the mimicking of selected properties of naturally occurring antisense RNAs in prokaryotes allows efficient inhibition of gene expression by in situ-expressed recombinant molecules in mammalian cells. Prokaryotic regulatory transcripts are expressed at high levels and have hairpin structures at their termini, features reminiscent of small nuclear RNAs (snRNAs) which are abundant and stable in the nucleus of all mammalian cells. A sequence complementary to fibrillin-1 (FBN1) mRNA, interrupted in its center by a hammerhead ribozyme, was substituted for the Sm protein binding site between the stem-loop structures of U1 snRNA.

Glanzmann thrombasthenia. Cooperation between sequence variants in cis during splice site selection.

Glanzmann thrombasthenia (GT), an autosomal recessive bleeding disorder, results from abnormalities in the platelet fibrinogen receptor, GP(IIb)-IIIa (integrin alpha(IIb)beta3). A patient with GT was identified as homozygous for a G-->A mutation 6 bp upstream of the GP(IIIa) exon 9 splice donor site. Patient platelet GP(IIIa) transcripts lacked exon 9 despite normal DNA sequence in all of the cis-acting sequences known to regulate splice site selection.

Mammalian orthologues of a yeast regulator of nonsense transcript stability.

All eukaryotes that have been studied to date possess the ability to detect and degrade transcripts that contain a premature signal for the termination of translation. This process of nonsense-mediated RNA decay has been most comprehensively studied in the yeast Saccharomyces cerevisiae where at least three trans-acting factors (Upf1p through Upf3P) are required. We have cloned cDNAs encoding human and murine homologues of Upf1p, termed rent1 (regulator of nonsense transcripts).

Both the wild type and a functional isoform of CFTR are expressed in kidney.

The cystic fibrosis transmembrane conductance regulator (CFTR) consists of five domains, two transmembrane-spanning domains, each composed of six transmembrane segments, a regulatory domain, and two nucleotide-binding domains (NBDs). CFTR is expressed in kidney, but its role in overall renal function is not well understood, because mutations in CFTR found in patients with cystic fibrosis are not associated with renal dysfunction. To learn more about the distribution and functional forms of CFTR in kidney, we used a combination of molecular, cell biological, and electrophysiological approaches.

Revised diagnostic criteria for the Marfan syndrome.

In 1986, the diagnosis of the Marfan syndrome was codified on the basis of clinical criteria in the Berlin nosology [Beighton et al., 1988]. Over time, weaknesses have emerged in these criteria, a problem accentuated by the advent of molecular testing.

Evaluation of inhA gene and catalase-peroxidase gene among isoniazid-sensitive and resistant Mycobacterium tuberculosis isolates.

The katG gene and the inhA gene of 30 INH-resistant (INH-R) and 28 INH-sensitive (INH-S) isolates of M. tuberculosis from Haiti and Maryland were analysed by PCR to establish the presence and frequency of two postulated mechanisms of INH-resistance, total katG gene deletion and inhA Ser94 to Ala94 amino acid substitution. Only two of 30 INH-R isolates (3%) appear to have total katG gene deletions.

Mutation in fibrillin-1 and the Marfanoid-craniosynostosis (Shprintzen-Goldberg) syndrome.

Recent reports have described a distinct and recurrent pattern of systemic malformation that associates craniosynostosis and neurodevelopmental abnormalities with many clinical features of the Marfan syndrome (MFS), an autosomal dominant disorder of the extracellular microfibril caused by defects in the gene encoding fibrillin-1, FBN1 (ref. 8). Additional common findings include other craniofacial anomalies, hypotonia, obstructive apnea, foot deformity, and congenital weakness of the abdominal wall.

The Marfan syndrome and the cardiovascular surgeon.

The authors present the current status of surgery for the cardiovascular manifestations of the Marfan syndrome. In addition, a brief review of current Marfan genetic research is presented. Data on all Marfan patients undergoing aortic root replacement at the Johns Hopkins Hospital (September 1976-June 1995) were analyzed.

Marfan syndrome as a paradigm for transcript-targeted preimplantation diagnosis of heterozygous mutations.

Among the many clinical applications of the polymerase chain reaction (PCR) is its potential use in preimplantation diagnosis of genetic disorders. Performing PCR on single blastomeres from early cleavage stage (six- to eight-cell) human embryos should, in principle, enable reliable determination of disease status for certain inherited conditions. However, reports of misdiagnoses using this technique have diminished enthusiasm for its widespread clinical use.

Fifteen novel FBN1 mutations causing Marfan syndrome detected by heteroduplex analysis of genomic amplicons.

Mutations in the gene encoding fibrillin-1 (FBN1), a component of the extracellular microfibril, cause the Marfan syndrome (MFS). This statement is supported by the observations that the classic Marfan phenotype cosegregates with intragenic and/or flanking marker alleles in all families tested and that a significant number of FBN1 mutations have been identified in affected individuals. We have now devised a method to screen the entire coding sequence and flanking splice junctions of FBN1.

Expression of a mutant human fibrillin allele upon a normal human or murine genetic background recapitulates a Marfan cellular phenotype.

The Marfan syndrome (MFS) is a connective tissue disorder inherited as an autosomal dominant trait and caused by mutations in the gene encoding fibrillin, a 350-kD glycoprotein that multimerizes to form extracellular microfibrils. It has been unclear whether disease results from a relative deficiency of wild-type fibrillin; from a dominant-negative effect, in which mutant fibrillin monomers disrupt the function of the wild-type protein encoded by the normal allele; or from a dynamic and variable interplay between these two pathogenetic mechanisms. We have now addressed this issue in a cell culture system.

Mutations in the human gene for fibrillin-1 (FBN1) in the Marfan syndrome and related disorders.

The extracellular microfibril, 10-14 nm in diameter, performs a number of functions, including serving as the scaffolding for deposition of tropoelastin to form elastic fibers. A variety of proteins compose the structure of microfibrils, the most prominent of which are the two fibrillins. Fibrillin-1 is encoded by FBN1 on human chromosome 15q21 and fibrillin-2 is encoded by FBN2 on 5q23.

Maintenance of an open reading frame as an additional level of scrutiny during splice site selection.

Although nonsense mutations have been associated with the skipping of specific constitutively spliced exons in selected genes, notably the fibrillin gene, the basis for this association is unclear. Now, using chimaeric constructs in a model in vivo expression system, premature termination codons are identified as determinants of splice site selection. Nonsense codon recognition prior to RNA splicing necessitates the ability to read the frame of precursor mRNA in the nucleus.

A molecular approach to the stratification of cardiovascular risk in families with Marfan's syndrome.

Background: The fibrillin gene encodes a protein in the extracellular matrix, and this protein is widely distributed in elastic tissues. The fibrillin gene is the site of mutations causing Marfan's syndrome. This disorder shows a high degree of clinical variability both between and within families.

Quantitative differences in biosynthesis and extracellular deposition of fibrillin in cultured fibroblasts distinguish five groups of Marfan syndrome patients and suggest distinct pathogenetic mechanisms.

Pulse-chase studies of [35S]cysteine-labeled fibrillin were performed on fibroblast strains from 55 patients with Marfan syndrome (MFS), including 13 with identified mutations in the fibrillin-1 gene and 10 controls. Quantitation of the soluble intracellular and insoluble extracellular fibrillin allowed discrimination of five groups. Groups I (n = 8) and II (n = 19) synthesize reduced amounts of normal-sized fibrillin, while synthesis is normal in groups III (n = 6), IV (n = 18), and V (n = 4).

A mutation in the surfactant protein B gene responsible for fatal neonatal respiratory disease in multiple kindreds.

To determine the molecular defect accounting for the deficiency of pulmonary surfactant protein B (SP-B) in full-term neonates who died from respiratory failure associated with alveolar proteinosis, the sequence of the SP-B transcript in affected infants was ascertained. A frameshift mutation consisting of a substitution of GAA for C in codon 121 of the SP-B cDNA was identified. The three affected infants in the index family were homozygous for this mutation, which segregated in a fashion consistent with autosomal recessive inheritance of disease.