Somatic Variant Analysis Identifies Targets for Tailored Therapies in Patients with Vascular Malformations.

Vascular malformations include various disorders characterized by morphological, structural and/or functional alterations of blood and lymph vessels. Most are sporadic, due to somatic mutations. Here, we report a cohort of patients with sporadic and/or unifocal vascular malformations, in whom we carried out next generation sequencing analysis of a panel of genes associated with vascular malformations. The 115 patients analyzed were from different clinical centres. In 37 patients (32%), we found pathogenic mutations: most of these were gain-of-function mutations in PIK3CA (18%, 21/115) and TEK (13/115, 11%). We also found mutations in GNAQ, CCM2 and PTEN. Identifying pathogenic variants in patients with vascular malformations can help improve management, particularly in cases with activating mutations that cause an increase in cell proliferation. Personalized pharmacological treatment, if possible, is now considered preferable to surgery and can help prevent recurrences, i.e., long-term complications of residual malformation or regrowth of tumors. For instance, rapamycin is currently being investigated for the treatment of various vascular malformations associated with hyperactivation of the phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway.

NT5E mutations and arterial calcifications.

BACKGROUND: Arterial calcifications are associated with increased cardiovascular risk, but the genetic basis of this association is unclear. METHODS: We performed clinical, radiographic, and genetic studies in three families with symptomatic arterial calcifications. Single-nucleotide-polymorphism analysis, targeted gene sequencing, quantitative polymerase-chain-reaction assays, Western blotting, enzyme measurements, transduction rescue experiments, and in vitro calcification assays were performed. RESULTS: We identified nine persons with calcifications of the lower-extremity arteries and hand and foot joint capsules: all five siblings in one family, three siblings in another, and one patient in a third family. Serum calcium, phosphate, and vitamin D levels were normal. Affected members of Family 1 shared a single 22.4-Mb region of homozygosity on chromosome 6 and had a homozygous nonsense mutation (c.662C→A, p.S221X) in NT5E, encoding CD73, which converts AMP to adenosine. Affected members of Family 2 had a homozygous missense mutation (c.1073G→A, p.C358Y) in NT5E. The proband of Family 3 was a compound heterozygote for c.662C→A and c.1609dupA (p.V537fsX7). All mutations found in the three families result in nonfunctional CD73. Cultured fibroblasts from affected members of Family 1 showed markedly reduced expression of NT5E messenger RNA, CD73 protein, and enzyme activity, as well as increased alkaline phosphatase levels and accumulated calcium phosphate crystals. Genetic rescue experiments normalized the CD73 and alkaline phosphatase activity in patients' cells, and adenosine treatment reduced the levels of alkaline phosphatase and calcification. CONCLUSIONS: We identified mutations in NT5E in members of three families with symptomatic arterial and joint calcifications. This gene encodes CD73, which converts AMP to adenosine, supporting a role for this metabolic pathway in inhibiting ectopic tissue calcification. (Funded by the National Human Genome Research Institute and the National Heart, Lung, and Blood Institute of the National Institutes of Health.).

An enhanced polymerase chain reaction assay to detect pre- and full mutation alleles of the fragile X mental retardation 1 gene.

Several diagnostic strategies have been applied to the detection of FMR1 gene repeat expansions in fragile X syndrome. Here, we report a novel polymerase chain reaction-based strategy using the Expand Long Template PCR System (Roche Diagnostics, Mannheim, Germany) and the osmolyte betaine. Repeat expansions up to approximately 330 CGGs in males and up to at least approximately 160 CGGs in carrier women could be easily visualized on ethidium bromide agarose gels. We also demonstrated that fluorescence analysis of polymerase chain reaction products was a reliable tool to verify the presence of premutation and full mutation alleles both in males and in females. This technique, primarily designed to detect premutation alleles, can be used as a routine first screen for expanded FMR1 alleles.

Fcgamma receptor IIA genotype and susceptibility to P. aeruginosa infection in patients with cystic fibrosis.

It has been suggested that genes other than CFTR could modulate the severity of lung disease in cystic fibrosis (CF). Neutrophil Fcgamma receptor II (FcgammaRII) is involved in host defense against microorganisms and in inflammatory response. We evaluated the association between genetic variability of this gene and both airway infection with Pseudomonas aeruginosa and severity of lung disease in patients with CF. We studied 167 Italian unrelated patients with CF and 50 control subjects. The distribution of FcgammaRIIA genotypes in CF patients was compared with that in control subjects and the different genotypes were related with the presence or absence of P. aeruginosa infection and markers of disease severity in CF patients. The distribution of FcgammaRIIA genotypes was not significantly different between CF patients and controls. We observed that in CF patients with the same CFTR genotype (DeltaF508/DeltaF508), those carrying the R allele of FcgammaRIIA had an increased risk of acquiring chronic P. aeruginosa infection (P=0.042, R.R.: 4.38; 95% CI: 1.17/22.4). Moreover, the frequency of R/R genotype in patients with chronic P. aeruginosa infection seems to be higher than that of control subjects and patients without chronic infection. The observation that CF patients carrying the R allele of FcgammaRIIA are at higher risk of acquiring chronic P. aeruginosa infection suggests that the FcgammaRII loci genetic variation is contributing to this infection susceptibility.