The increasing use of advanced nucleic acid sequencing technologies for clinical diagnostics and therapeutics has made vital understanding the costs of performing these procedures and their value to patients, providers, and payers. The Association for Molecular Pathology invested in a cost and value analysis of specific genomic sequencing procedures (GSPs) newly coded by the American Medical Association Current Procedural Terminology Editorial Panel. Cost data and work effort, including the development and use of data analysis pipelines, were gathered from representative laboratories currently performing these GSPs. Results were aggregated to generate representative cost ranges given the complexity and variability of performing the tests. Cost-impact models for three clinical scenarios were generated with assistance from key opinion leaders: impact of using a targeted gene panel in optimizing care for patients with advanced non-small-cell lung cancer, use of a targeted gene panel in the diagnosis and management of patients with sensorineural hearing loss, and exome sequencing in the diagnosis and management of children with neurodevelopmental disorders of unknown genetic etiology. Each model demonstrated value by either reducing health care costs or identifying appropriate care pathways. The templates generated will aid laboratories in assessing their individual costs, considering the value structure in their own patient populations, and contributing their data to the ongoing dialogue regarding the impact of GSPs on improving patient care.

Marfan syndrome (MFS) is an autosomal dominantly inherited connective tissue disorder characterized by cardiovascular, ocular and skeletal manifestations. Previously, mutations in the fibrillin-1 gene on chromosome 15 (FBN1) have been reported to cause MFS. We have now screened 44 probands with MFS or related phenotypes for alterations in the entire fibrillin coding sequence (9.3 kb) by single strand conformation analysis. We report four unique mutations in the fibrillin gene of unrelated MFS patients. One is a 17 bp deletion and three are missense mutations, two of which involve 8-cysteine motifs. Another missense mutation was found in two unrelated individuals with annuloaortic ectasia but was also present in unaffected relatives and controls from various ethnic backgrounds. By using allele-specific oligonucleotide hybridization, we screened 65 unrelated MFS patients, 29 patients with related phenotypes and 84 control individuals for these mutations as well as for a previously reported mutation and two polymorphisms. Our results suggest that most MFS families carry unique mutations and that the fibrillin genotype is not the sole determinant of the connective tissue phenotype.

Dermal fibroblasts from nine Marfan syndrome patients with missense mutations in the fibrillin-1 gene (FBN1) produced nearly normal amounts of fibrillin as determined by quantitative pulse-chase experiments. However, six of the seven mutations involving substitutions of highly conserved cysteine residues exhibited lower rates of intracellular transport and secretion. This effect is likely due to improper folding, since intracellular fibrillin processing was also affected by the reducing agent dithiothreitol. Normal secretion patterns were seen in three mutations that either change the conformation of EGF-like domains or change consensus amino acids required for Ca(++)-binding. In all nine fibroblasts strains, however, the deposition of fibrillin in the extracellular matrix was reduced to 50% of normal in two and to less than 30% in seven of the nine samples studied. The protein alterations caused by these missense mutations are associated with moderate to severe features of Marfan syndrome and a dominant negative mechanism is suggested to play a major role in their pathogenesis.

We report here the band location of 540 cosmids mapped to chromosome 19. The cosmids were mapped by fluorescence in situ hybridization (FISH) relative to chromosomal bands produced by DAPI/actinomycin staining. The cosmids are distributed throughout the chromosome, with a sampling bias for the q-arm. A detailed analysis of the distribution of three different subtelomeric and 22 pericentromeric chromosome 19 cosmids on other chromosomes is also reported. Colony hybridization identified 142 cosmids that contain sequences representing genes or DNA markers that map to chromosome 19. FISH mapping of these cosmids sublocalizes a total of 70 genes and DNA markers on chromosome 19, revises the previously published map assignments of 2 genes, and narrows the location of over 20 markers.