Joubert Syndrome and related disorders

Joubert syndrome (JS) and related disorders (JSRD) are a group of developmental delay/multiple congenital anomalies syndromes in which the obligatory hallmark is the molar tooth sign (MTS), a complex midbrain-hindbrain malformation visible on brain imaging, first recognized in JS. Estimates of the incidence of JSRD range between 1/80,000 and 1/100,000 live births, although these figures may represent an underestimate. The neurological features of JSRD include hypotonia, ataxia, developmental delay, intellectual disability, abnormal eye movements, and neonatal breathing dysregulation. These may be associated with multiorgan involvement, mainly retinal dystrophy, nephronophthisis, hepatic fibrosis and polydactyly, with both inter- and intra-familial variability. JSRD are classified in six phenotypic subgroups: Pure JS; JS with ocular defect; JS with renal defect; JS with oculorenal defects; JS with hepatic defect; JS with orofaciodigital defects. With the exception of rare X-linked recessive cases, JSRD follow autosomal recessive inheritance and are genetically heterogeneous. Ten causative genes have been identified to date, all encoding for proteins of the primary cilium or the centrosome, making JSRD part of an expanding group of diseases called "ciliopathies". Mutational analysis of causative genes is available in few laboratories worldwide on a diagnostic or research basis. Differential diagnosis must consider in particular the other ciliopathies (such as nephronophthisis and Senior-Loken syndrome), distinct cerebellar and brainstem congenital defects and disorders with cerebro-oculo-renal manifestations. Recurrence risk is 25% in most families, although X-linked inheritance should also be considered. The identification of the molecular defect in couples at risk allows early prenatal genetic testing, whereas fetal brain neuroimaging may remain uninformative until the end of the second trimester of pregnancy. Detection of the MTS should be followed by a diagnostic protocol to assess multiorgan involvement. Optimal management requires a multidisciplinary approach, with particular attention to respiratory and feeding problems in neonates and infants. Cognitive and behavioral assessments are also recommended to provide young patients with adequate neuropsychological support and rehabilitation. After the first months of life, global prognosis varies considerably among JSRD subgroups, depending on the extent and severity of organ involvement

Aberrations of chromosome No. 1 in blastic phase of chronic myeloid leukemia

Aberrations of chromosome No. 1 were detected at the time of blastic crisis in 7 patients with Ph1-positive chronic myeloid leukemia (CML). Two patients had trisomy 1; trisomy for a long arm segment of chromosome No. 1 was present in 2 patients; trisomy for a short arm segment occurred in 2 patients; and one patient had an apparently balanced translocation affecting chromosome No. 1. All patients with extra material of chromosome No. 1 were trisomic for the region 1p22–1pter or 1q21–1qter. A survey of abnormalities of chromosome No. 1 in this series and in other patients with CML previously reported show, in all patients, a relative increase or decrease of genetic material of two specific regions: 1q32–1q42 and 1p36–1pter

Atrioventricular canal defect and associated genetic disorders: new insights into polydactyly syndromes

Atrioventricular canal defect (AVCD) is a common congenital heart defect (CHD), representing 7.4% of all cardiac malformations, considered secondary to an extracellular matrix anomaly. The AVCD is associated with extracardiac defects in about 75% of the cases. In this review we analyzed different syndromic AVCDs, in particular those associated with polydactyly disorders, which show remarkable genotype-phenotype correlations. Chromo - some imbalances more frequently associated with AVCD include Down syndrome, deletion 8p23 and deletion 3p25, while mendelian disorders include Noonan syndrome and related RASopathies, several polydactyly syndromes, CHARGE and 3C (cranio-cerebello-cardiac) syndrome. The complete form of AVCD is prevalent in patients with chromosomal imbalances. Additional cardiac defects are found in patients affected by chromosomal imbalances different from Down syndrome. Left-sided obstructive lesions are prevalently found in patients with RASopathies. Patients with deletion 8p23 often display AVCD with tetralogy of Fallot or with pulmonary valve stenosis. Tetralogy of Fallot is the only additional cardiac defect found in patients with Down syndrome and AVCD. On the other hand, the association of AVCD and tetralogy of Fallot is also quite characteristic of CHARGE and 3C syndromes. Heterotaxia defects, including common atrium and anomalous pulmonary venous return, occur in patients with AVCD associated with polydactyly syndromes (Ellis-van Creveld, short rib polydactyly, oral-facial-digital, Bardet-Biedl, and Smith-Lemli-Opitz syndromes). The initial clinical evidence of anatomic similarities between AVCD and heterotaxia in polydactyly syndromes was corroborated and explained by experimental studies in transgenic mice. These investigations have suggested the involvement of the Sonic Hedgehog pathway in syndromes with postaxial polydactyly and heterotaxia, and ciliary dysfunction was detected as pathomechanism for these disorders. Anatomic differences in AVCD in the different groups are probably due to different genetic causes

Obituary of Dr. Angelo Di George

[No abstract available

Use of DHPLC for rapid screening of recombinant clones.

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Sequence-specific modification of a β-thalassemia locus by small DNA fragments in human erythroid progenitor cells

Gene therapy has been proposed as a definitive cure of beta-thalassemia. We applied a gene targeting approach, based on the introduction of small DNA fragments (SDF) into erythroid progenitor cells, to specifically modify the beta-globin gene sequence at codon 39. The strategy was first tested in normal individuals by delivering mutant SDF that were able to produce the beta-39 (C-T) mutation. Secondly, wild-type SDF were electroporated into target cells of beta-3i9/beta-39 b-thalassemic patients to correct the endogenous mutation. In both cases, gene modification was assayed by allele-specific polymerase chain reaction of DNA and mRNA, by restriction fragment length polymorphism analysis and by direct sequencing

Quantification of Small Non-Coding RNAs Allows an Accurate Comparison of miRNA Expression Profiles

MicroRNAs (miRNAs) are highly conserved ∼22-mer RNA molecules, encoded by plants and animals that regulate the expression of genes binding to the 3′-UTR of specific target mRNAs. The amount of miRNAs in a total RNA sample depends on the recovery efficiency that may be significantly affected by the different purification methods employed. Traditional approaches may be inefficient at recovering small RNAs, and common spectrophotometric determination is not adequate to quantify selectively these low molecular weight (LMW) species from total RNA samples. Here, we describe the use of qualitative and quantitative lab-on-a-chip tools for the analysis of these LMW RNA species. Our data emphasize the close correlation of LMW RNAs with the expression levels of some miRNAs. We therefore applied our result to the comparison of some miRNA expression profiles in different tissues. Finally, the methods we used in this paper allowed us to analyze the efficiency of extraction protocols, to study the small (but significant) differences among various preparations and to allow a proper comparison of some miRNA expression profiles in various tissues