A novel homozygous RTEL1 variant in a consanguineous Lebanese family: phenotypic heterogeneity and disease anticipation.

Phenotypic heterogeneity is often observed in patients with telomeropathies caused by pathogenic variants in telomere biology genes. However, the roles of recessive variants in these different phenotypes are not fully characterized. Our goal is to describe the biological roles of a novel homozygous RTEL1 variant identified in a consanguineous Lebanese family with unusual presentation of telomeropathies. A proband was screened for germline variants in telomere biology genes by whole exome sequencing. Leukocytes' telomere length was measured in the proband and eight relatives. We identified a novel homozygous p.E665K RTEL1 variant in the proband, his mother, and seven siblings that associated with telomere shortening and a broad spectrum of clinical manifestations, ranging from mild unspecific findings to severe phenotypes. Consanguinity in at least three family generations led to increased frequency of the homozygous p.E665K variant in the youngest generation and progressive telomere shortening. The increased frequency of the homozygous RTEL1 variant due to consanguinity in this Lebanese family allowed us to infer novel behaviors of recessive RTEL1 variants, as the expressivity and penetrance of this gene are very heterogenous between inter- and intra-generations. Progressive telomere shortening was associated with disease anticipation, first reported in recessive autosomal telomeropathies. Both genetic testing and telomere length measurement were critical for the clinical diagnosis of this family with telomere diseases marked by phenotypic heterogeneity.

Disseminated Gastric MALT Lymphoma with Monoclonal Gammopathy, t(11;18)(q21;q21), and Subsequent Development of T-Large Granular Lymphocytic Leukemia: A Case Report and Review of the Literature.

Background. Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) is a well-characterized entity that may share clinical and morphological findings with other low-grade non-Hodgkin's lymphomas. Dissemination of MALT-type lymphoma to bone marrow and peripheral blood simultaneously with the presence of T-large granular cell leukemia (T-LGL) has rarely been reported. Case Presentation. This is the case of a 42-year-old male who presented with a gastric MALT-type lymphoma, disseminated to the bone marrow and the peripheral blood with high serum IgM levels and t(11;18)(q21;q21). The morphological, immunophenotypical and, immunohistochemical studies of the successive bone marrow and peripheral blood samples had revealed the coexistence of two distinct lymphoma cell populations: a B-cell, marginal zone type population expressing CD19, CD20, CD22, CD79b, IgM, and kappa light chain, and a T-large granular cell population, developed after treatment with rituximab expressing CD3, CD8, CD5, CD7, and CD45. Conclusion. Based on the analysis of this unusual case we performed an extensive review of the literature to elucidate the relationship between T-LGL and B-cell lymphomas and to emphasize the importance of paraprotein analysis at diagnosis of gastric MALT lymphoma.

A nationwide non-interventional epidemiological data registry on myelodysplastic syndromes in Lebanon.

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal hematopoietic disorders characterized by peripheral blood cytopenias, blood cells dysplasia, and increased risk for progression to acute leukemia.Physicians should be vigilant in diagnosing MDS and should be aware of the contemporary therapies that are always in progress. Most of the data on MDS epidemiology and management comes from developed countries. The incidence and features of MDS in the Arab countries, among them Lebanon, are not known. We undertook a nationwide epidemiological registry study of all newly diagnosed MDS cases through 2010-2011. Patients were referred by 21 hematologists/oncologists practicing in 17 hospitals and medical centers distributed across the entire country. 58 patients (29 males and 29 females) with confirmed MDS were included. The calculated incidence rate of MDS was 0.71 per 100,000 people. The median age at diagnosis was 73 years (range 16-86). The most common complaints on presentation were fatigue (70.7%), weakness (60.3%) and pallor (43.1%). Most patients were diagnosed as refractory anemia with excess blasts (RAEB; 36.2%) and refractory cytopenia with multilineage dysplasia (RCMD; 32.8%). This paper constitutes the first epidemiological report on the incidence and specific subtypes of MDS in Lebanon.