Next generation sequencing analysis of patients with familial cervical artery dissection.

BACKGROUND: The cause of cervical artery dissection is not well understood. We test the hypothesis that mutations in genes associated with known arterial connective tissue disorders are enriched in patients with familial cervical artery dissection. PATIENTS AND METHODS: Patient duos from nine pedigrees with familial cervical artery dissection were analyzed by whole exome sequencing. Single nucleotide variants in a panel of 11 candidate genes (ACTA2, MYH11, FBN1, TGFBR1, TGFBR2, TGFB2, COL3A1, COL4A1, SMAD3, MYLK and SLC2A10) were prioritized according to functionality (stop-loss, nonsense, and missense variants with polyphen-2 score ≥0.95). Variants classified as "benign" or "likely benign" in the ClinVar database were excluded from further analysis. For comparison, non-benign stop-loss, nonsense and missense variants with polyphen-2 score ≥0.95 in the same panel of candidate genes were identified in the European non-Finnish population of the ExAC database (n = 33,370). RESULTS: Non-benign Single nucleotide variants in both affected patients were identified in four of the nine cervical artery dissection families (COL3A1; Gly324Ser, FBN1: Arg2554Trp, COL4A1: Pro116Leu, and TGFBR2: Ala292Thr) yielding an allele frequency of 22.2% (4/18). In the comparison group, 1782 variants were present in 33,370 subjects from the ExAC database (allele frequency: 1782/66,740 = 2.7%; p = 0.0008; odds ratio = 14.2; 95% confidence interval = 3.8-52.9). CONCLUSION: Cervical artery dissection families showed enrichment for non-benign variants in genes associated with arterial connective tissue disorders. The observation that findings differed across families indicates genetic heterogeneity of familial cervical artery dissection.

Nerve ultrasound in the differentiation of multifocal motor neuropathy (MMN) and amyotrophic lateral sclerosis with predominant lower motor neuron disease (ALS/LMND).

The objective of the study was to investigate nerve ultrasound (US) in comparison to nerve conduction studies (NCS) for differential diagnosis of amyotrophic lateral sclerosis with predominant lower motoneuron disease(ALS/LMND) and multifocal motor neuropathy(MMN). A single-center, prospective, examiner-blinded cross-sectional diagnostic study in two cohorts was carried out. Cohort I: convenience sample of subjects diagnosed with ALS/LMND or MMN (minimal diagnostic criteria:possible ALS (revised EL-Escorial criteria), possible MMN (European Federation of Neurosciences guidelines).Cohort II: consecutive subjects with suspected diagnosis of either ALS/LMND or MMN. Diagnostic US and NCS models were developed based on ROC analysis of 28 different US and 32 different NCS values measured in cohort I. Main outcome criterion was sensitivity/specificity of these models between ALS/LMND and MMN in cohort II.Cohort I consisted of 16 patients with ALS/LMND and 8 patients with MMN. For cohort II, 30 patients were recruited, 8 with ALS/LMND, 5 with MMN, and 17 with other diseases. In cohort I, the three best US measures showed higher mean ± SD areas under the curve than the respective NCS measures (0.99 ± 0.01 vs. 0.79 ± 0.03, p<0.001; two-sided t test). The US model with highest measurement efficacy (8 values) and diagnostic quality reached 100 % sensitivity and 92 % specificity for MMN in cohort II, while the respective NCS model (6 values, including presence of conduction blocks) reached 100 and 52 %. Nerve US is of high diagnostic accuracy for differential diagnosis of ALS/LMND and MMN. It might be superior to NCS in the diagnosis of MMN in hospital-admitted patients with this differential diagnosis.

Familial occurrence of cervical artery dissection--coincidence or sign of familial predisposition?

UNLABELLED: BACKGROUNDAND PURPOSE: The etiology of spontaneous cervical artery dissection (CeAD) is poorly understood in most patients. Mild cervical trauma preceding the dissection event is a common finding, but many CeAD occur spontaneously. It is likely that genetic factors may increase the risk for CeAD. However, familial cases are excedingly rare. Familial clustering of CeAD may be accidental or associated with genetic or environmental risk factors shared between affected relatives. In this explorative study, we aim to show that specific risk factors for familial CeAD exist. METHODS: Age of onset, sex, affected artery and number of recurrent CeAD were documented for familial patients and compared with published findings from patients with sporadic CeAD. Concordance of age, sex and dissected artery within the families was analyzed by correlation analysis and by analysis of variance or Kruskal-Wallis testing. RESULTS: The study sample consisted of 9 new patients with a family history of CeAD enrolled in the Neurology Department of the University of Heidelberg or referred to Heidelberg from other centers. The study sample also included published findings from another 23 patients, in total 32 patients. The mean age of the patients with familial CeAD at their first dissections was 38.4 ± 13.3 years. Twenty (62.5%) patients were female and 12 patients (37.5%) suffered multiple dissections. Four patients (12.5%) presented with recurrent dissections after >1 year. Patients with a familial history of CeAD were younger (p = 0.023) and presented more often with multiple dissections (p = 0.024) and recurrent dissections (p = 0.018). Age at the first event (correlation analysis p = 0.026; analysis of variance p = 0.029) and site of the dissection (correlation analysis p = 0.032; Kruskal-Wallis test p = 0.018) differed between the families, and there was no concordance of gender of affected family members (correlation analysis p = 0.500; Kruskal-Wallis test p = 0.211). CONCLUSIONS: The high prevalence of multiple dissection events and of long-term (>1 year) recurrent dissections in patients with a familial history of CeAD indicates that a specific predisposition for familial CeAD exists. Since age of onset and affected vessel differ between families, the risk profile for familial CeAD is heterogeneous. A large-scale (whole exome) sequencing analysis of 14 patients from 7 of the analyzed families is currently being performed in order to identify causative genetic variants.