Atypical presentations of 22q11.2 deletion syndrome: explaining the genetic defects and genome architecture.

22q11.2 deletion syndrome, the most common microdeletion syndrome, exhibits a broad range of phenotypes, implying a cumbersome diagnosis due to atypical or paucisymptomatic presentations. We present two atypical cases of 22q11.2 deletion syndrome and suggest a preferential occurrence of the breakpoints in regions poor in repetitive elements of SINE/Alu family.

Variant e19a2 BCR-ABL1 fusion transcript in typical chronic myeloid leukemia.

BACKGROUND: The landmark of chronic myeloid leukemia (CML) is the reciprocal translocation t(9;22)(q34;q11), generating the BCR-ABL1 hybrid gene. About 15 types of fusion transcripts have been described to date. Among the rarer types, e19a2 was described for the first time in 1990 by Saglio et al. (1). Here, we report on a new case of CML with the e19a2 transcript. METHODS: A 38 year-old male patient was referred for genetic investigations with a clinical diagnosis of CML. Karyotyping and molecular genetics investigations (reverse-transcription and sequencing) were performed. RESULTS: t(9;22)(q34;q11.2) was found in 100% of metaphases and the patient's BCR-ABL1 fusion gene showed the rare variant transcript e19a3 with no sequence alterations. CONCLUSIONS: CML with e19a2 fusion transcript is a rare disease with a large variety of clinical manifestations and unclear biological significance. Adding new cases to the current knowledge will contribute to the understanding of its mechanisms and the clarification of its prognosis.

Autism and severe clinical phenotype in a patient with 8p21.2p11.21 deletion: Case report and literature review.

Interstitial 8p deletions were previously described, in literature and databases, in approximately 30 patients with neurodevelopmental disorders. We report on a novel patient with a 8p21.2p11.21 deletion presenting a clinical phenotype that includes severe intellectual disability, microcephaly, epilepsy, and autism, the latter having been rarely associated with this genetic defect.

3p interstitial deletion: novel case report and review.

3p interstitial deletions have emerged in recent years as a new cause of neurodevelopmental delay and intellectual disability. Since the first report of this condition in 1979, 16 cases have been described in the literature, delineating it as a presumptive syndrome. Here, we add a novel case presenting severely delayed neurodevelopment and psychomotor development; facial dysmorphism (square facies, broad forehead, short palpebral fissures, epicanthic folds, broad nasal bridge, and low-set malformed ears); cerebral, cardiac, and genital malformations; hand and feet anomalies; sacral sinus; and hearing impairment. Genetic investigations revealed a del(3)(p12.3p14.1) of 12.5 Mb, including 31 ORFs, among which ROBO2, PDZRN3, MITF, and FOXP1 are known to act in neurodevelopment. The clinical features of our patient are compared with those previously reported in the literature, thus providing further support for the delineation of the 3p interstitial deletion syndrome.

Involvement of Saccharomyces cerevisiae Pdr5p ATP-binding cassette transporter in calcium homeostasis.

Deletion of PDR5 gene (Deltapdr5) in Saccharomyces cerevisiae led to increased resistance to calcium. The cellular Ca2+ level in the presence of high calcium as estimated by reporter assay in Deltapdr5 cells was significantly lower than that in wild-type cells. Membrane Pdr5p levels diminished rapidly during incubation with high calcium in a manner dependent on calcineurin and Pep4p, suggesting a feedback regulatory mechanism for Pdr5p abundance.

Mutational analysis of the yeast multidrug resistance ABC transporter Pdr5p with altered drug specificity.

Multidrug resistance ABC transporter Pdr5p of Saccharomyces cerevisiae is particularly important due to its ability to export a wide range of unrelated substrates. To clarify its function, we generated Pdr5p mutants by random mutagenesis and screened for mutants with altered drug specificity in vivo by using 5 drug compounds. Nine point mutations that caused significant changes in drug specificity distributed throughout the length of Pdr5p, namely, in the extracellular, transmembrane or cytoplasmic regions of the transporter. We then investigated their effects upon drug resistance, using 36 chemically related or distinct substrates. From this study, overall geometry of the Pdr5p was suggested to contribute in acquiring the enormous range of drug specificity. Based on their ability to inhibit the growth of the mutant strains, the 36 tested drugs were classified into: drugs to which the mutants responded differently (Group 1), drugs to which all the mutants showed sensitivity (Group 2), and drugs to which all the mutants exhibited resistance (Group 3). The ability of the compounds to be partitioned to the plasma membrane seemed an important factor for recognition by Pdr5p.