De novo Diagnosis of Fabry Disease among Italian Adults with Acute Ischemic Stroke or Transient Ischemic Attack.

BACKGROUND AND PURPOSE: Cerebrovascular complications are often the first cause of hospitalization in patients with Fabry disease (FD). Screenings for FD among stroke patients have yielded discrepant results, likely as a result of heterogeneous or incomplete assessment. We designed a study to identify FD among adults 60 years of age or younger who were consecutively admitted for acute ischemic stroke or transient ischemic attack (TIA) to a stroke neurology service in Italy. METHODS: Patients with first-ever or recurrent events were included, irrespective of gender, risk factors, or stroke type. We screened male patients using α-galactosidase A enzyme assay, and female patients using DNA sequencing. FD was eventually established after a broad multidisciplinary discussion. RESULTS: We screened 108 patients (61% males, median age: 48 years); 84% of these patients had stroke. De novo FD diagnosis was established in 3 patients (2.8%; 95% confidence interval, .57-8.18): a 59-year-old man with recurrent lacunar-like strokes and multiple risk factors; a 42-year-old woman with recurrent cryptogenic minor strokes; and a 32-year-old woman with recurrent strokes previously attributed to Behçet's disease. Screened patients were systematically asked for typical FD symptoms; each of the de novo patients reported one or more of the following: episodes of hand/foot pain during fever, angiokeratoma, and family history of heart disease. In all of the patients events were recurrent, and lacunar-like infarcts characterized their brain imaging. CONCLUSIONS: Prevalence of FD among nonselected adults 60 years of age or younger with acute ischemic stroke or TIA is not negligible. A systematic search for FD in a stroke setting, using a comprehensive clinical, biochemical, and genetic screening protocol, may be worthwhile.

The Val142Ile transthyretin cardiac amyloidosis: not only an Afro-American pathogenic variant? A single-centre Italian experience.

Transthyterin amyloidosis is a life-threatening disorder caused by the deposition of hepatocyte-derived transthyretin (TTR) amyloid in various tissues and organs. The most common worldwide pathogenic variant with almost exclusive cardiac involvement is Val142Ile with an allele frequency of 3.5% in U.S. African-American population, but supposed extremely rare, with only sporadic cases in Caucasian patients. Unexpectedly, in our amyloidosis referral centre, we identified five patients (15.1% of all TTRm diagnosed patients, three families, two singleton) with Val142Ile variant belonging to unrelated families of Caucasian origin. Molecular study was performed in a total of 10 individuals of which three were Italian families (three affected individuals and five unaffected individuals) and two were singleton (one Italian patient and one patient from Argentine with Spanish ancestry). Sequence analysis of TTR gene revealed the presence of the heterozygous Val142Ile in the five affected patients and in five asymptomatic individuals. All probands underwent, at diagnosis, a complete clinical, echocardiographic and biohumoral evaluation. To the best of our knowledge, we describe the larger report of Caucasian patients with Val142Ile cardiomyopathy. All patients at diagnosis showed symptoms of heart failure with increased thickness of left ventricular walls and systo-diastolic left ventricular dysfunction. They also showed increased plasma values of NT-proBNP and troponin I. Our data confirm that Caucasian patients with the Val142Ile pathogenic variant have phenotypic manifestations similar to that of African-American one. Moreover, our data clearly show that Val142Ile pathogenic variant is not only an African-American mutation but could be also an underestimated Caucasian variant.

A Systematic Assessment of Accuracy in Detecting Somatic Mosaic Variants by Deep Amplicon Sequencing: Application to NF2 Gene.

The accurate detection of low-allelic variants is still challenging, particularly for the identification of somatic mosaicism, where matched control sample is not available. High throughput sequencing, by the simultaneous and independent analysis of thousands of different DNA fragments, might overcome many of the limits of traditional methods, greatly increasing the sensitivity. However, it is necessary to take into account the high number of false positives that may arise due to the lack of matched control samples. Here, we applied deep amplicon sequencing to the analysis of samples with known genotype and variant allele fraction (VAF) followed by a tailored statistical analysis. This method allowed to define a minimum value of VAF for detecting mosaic variants with high accuracy. Then, we exploited the estimated VAF to select candidate alterations in NF2 gene in 34 samples with unknown genotype (30 blood and 4 tumor DNAs), demonstrating the suitability of our method. The strategy we propose optimizes the use of deep amplicon sequencing for the identification of low abundance variants. Moreover, our method can be applied to different high throughput sequencing approaches to estimate the background noise and define the accuracy of the experimental design.