Molecular cytogenetic and phenotypic characterization of ring chromosome 13 in three unrelated patients.

We report on the cytogenetic and molecular investigations of constitutional de-novo ring chromosome 13s in three unrelated patients for better understanding and delineation of the phenotypic variability characterizing this genomic rearrangement. The patient's karyotypes were as follows: 46,XY,r(13)(p11q34) dn for patients 1 and 2 and 46,XY,r(13)(p11q14) dn for patient 3, as a result of the deletion in the telomeric regions of chromosome 13. The patients were, therefore, monosomic for the segment 13q34 → 13qter; in addition, for patient 3, the deletion was larger, encompassing the segment 13q14 → 13qter.

Multiple myeloma following essential thrombocythemia.

The association of essential thrombocythemia and multiple myeloma is extremely rare, with only three patients previously treated with hydroxyurea reported in the literature until now. In this paper, we report the case of a 66 year old male who developed IgG-kappa M six years after the diagnosis of essential thrombocythemia, for which he had received hydroyurea. The possible etiological and pathogenic link between both these entities is here discussed.

8p21.3 deletion suggesting a probable role of TRAIL-R1 and TRAIL-R2 as candidate tumor suppressor genes in the pathogenesis of multiple myeloma.

8p21.3 deletion was recently characterized in B cell lymphoma suggesting that TRAIL-R1 and TRAIL-R2 may be the target of the deletion and act as dosage-dependent tumor suppressor genes. As multiple myeloma is a plasma cell malignancy originating from B-lineage clonogenic cells, the idea was why do not evaluate this deletion in this pathology.

Cytogenetic analysis in a large series of children with non-syndromic mental retardation.

Mental retardation affects 1-3% of the population. To evaluate the implication of chromosomal abnormalities in the etiology of mental retardation, 1420 patients with non-syndromic mental retardation recruited at the department of cytogenetics of Farhat Hached hospital (Sousse, Tunisia) between January 2005 and December 2009, were analyzed using standard cytogenetic techniques. Age ranged between 3 and 18 years with a median of 8 years.

Chromosomal microarray analysis of functional Xq27-qter disomy and deletion 3p26.3 in a boy with Prader-Willi like features and hypotonia.

Duplications of the long arm of the X chromosome are rare. The infantile phenotype shares some resemblance with the Prader-Willi syndrome, presenting severe psychomotor retardation, facial dysmorphic features with a broad face, a small mouth and a thin pointed nose, hypotonia, urogenital malformation and proneness to infections. We report a boy with an additional Xq27-qter chromosome segment translocated onto the short arm of chromosome 3.