Fatal thoracic aortic aneurysm and dissection in a large family with a novel MYLK gene mutation: delineation of the clinical phenotype.

BACKGROUND: Thoracic and abdominal aortic aneurysms and dissection often develop in hypertensive elderly patients. At higher risk are smokers and those who have a family history of aortic aneurysms. In most affected families, the aortic aneurysms and dissection is inherited in an autosomal dominant manner with decreased penetrance and variable expressivity. Mutations at two chromosomal loci, TAA1 at 11q23 and the TAA2 at 5q13-14, and eight genes, MYLK, MYH11, TGFBR2, TGFBR1, ACTA2, SMAD3, TGFB2, and MAT2A, have been identified as being responsible for the disease in 23% of affected families. RESULTS: Herein, we inform on the clinical, genetic and pathological characteristics of nine living and deceased members of a large consanguineous Arab family with thoracic aortic aneurysm and dissection who carry a missense mutation c.4471G > T (Ala1491Ser), in exon 27 of MYLK gene. We show a reduced kinase activity of the Ala1491Ser protein compared to wildtype protein. This mutation is expressed as aortic aneurysm and dissection in one of two distinct phenotypes. A severe fatal and early onset symptom in homozygous or mild late onset in heterozygous genotypes. CONCLUSIONS: We found that MYLK gene Ala1491Ser mutation affect the kinase activity and clinically, it presents with vascular aneurysms and dissection. We describe a distinct genotype phenotype correlation where; heterozygous patients have mild late onset and incomplete penetrance disease compared with the early onset severe and generally fatal outcome in homozygous patients.

Absolute monocytosis at diagnosis correlates with survival in diffuse large B-cell lymphoma-possible link with monocytic myeloid-derived suppressor cells.

Some patients with lymphoma have monocytosis at diagnosis, but its significance is unclear. The recently recognized subpopulation, monocytic myeloid-derived suppressor cells (M-MDSCs), has immunoregulatory function, suppresses host anti-tumour immunity and plays a role in cancer tolerance. Data from 91 untreated patients with diffuse large B-cell lymphoma (DLBCL) were evaluated for monocytosis >1000/mm(3) at diagnosis and its significance compared with a number of well-established prognostic factors for DLBCL including age, stage, gender, B symptoms, extranodal sites, LDH and CRP levels, bone marrow involvement and International Prognostic Index (IPI) score. In 23 of these patients with DLBCL and 15 healthy controls, the proportion of M-MDSCs in the peripheral blood was determined by flow cytometry. Monocytosis was found in 17.6% of the patient cohort examined. In the multivariate analysis, bone marrow involvement, IPI score and monocytosis were the only independent prognostic factors seen to be associated with decreased progression free and overall survival. Patients with DLBCL had on average increased M-MDSCs counts at diagnosis compared with controls, which returned to normal after achieving remission. In conclusion, monocytosis was identified as an independent prognostic factor in DLBCL and correlated with worse overall survival. The significant increases in the M-MDSCs pool observed in some of the cases examined may possibly help to explain why monocytosis is associated with poor outcome in these patients.