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Mucopolysaccharidosis type II or Hunter syndrome is an X-linked lysosomal storage disease caused by a mutation in the gene encoding the lysosomal enzyme iduronate-2-sulfatase. The consequent enzyme deficiency causes a progressive, multisystem accumulation of glycosaminoglycans, which is the cause of the clinical manifestations involving also Central Nervous System for patients with the severe form of disease. The limits of the currently available therapies for Hunter syndrome, hematopoietic stem cell transplantation and recombinant enzyme replacement therapy, mainly regarding brain achievement, have encouraged several studies which recognized gene therapy as a potential therapeutic option for this condition. In vitro studies firstly aimed at the demonstration that viral vector- mediated IDS gene expression could lead to high levels of enzyme activity in transduced cells. The encouraging results obtained allowed the realization of many preclinical studies investigating the utilization of gene therapy vectors in animal models of Mucopolysaccharidosis II, together with a phase I clinical trial approved for Hunter patients affected by the mild form of the disease. Together to in vivo studies in which recombinant vectors are directly administered, systematically or by direct injection into Central Nervous System, also ex vivo gene therapy, consisting in transplantation of autologous hematopoietic stem cells, modified in vitro, into the animal or patient, has been tested. A wider clinical application of the results obtained so far is essential to ensure that gene therapy can be definitively validated as a therapeutic option available and usable for this rare but life-threatening disorder.

Background Parkinson's disease (PD) is the second most common neurodegenerative disorder, and the most common neurodegenerative form of parkinsonism. Recently, a pathogenic mutation (p.N855S) in DNAJC13 was linked to autosomal dominant Lewy body PD in a Dutch–German–Russian Mennonite multi-incident kindred, and was found in five additional patients. In this study, we performed a comprehensive screening of the DNAJC13 gene in familial PD and sporadic PD to assess the frequency of known and novel rare nonsynonymous variants. Methods We screened 563 sporadic and 168 familial PD patients and a control series (n = 1000) for the coding region of DNAJC13. Results Our sequencing analysis identified two carriers of the c.2708G > A (p.R903K) variant in exon 24 of DNAJC13. One of these carriers is a familial PD. Conclusion The p. R903K variant was not found in 1000 healthy controls and it is localized in a functional domain of the DNAJC13 protein. Further studies are necessary to evaluate the role of DNAJC13 variants in PD.

The insulin-like growth factors (IGFs; somatomedins) comprise a family of peptides that play important roles in mammalian growth and development. The principal members of this family are IGF1 and IGF2. IGF1 (somatomedin C), a 70 residue basic polypeptide, mediates many of the growth promoting actions of growth hormone (GH) and has metabolic and mitogenic effects.1 The major source of circulating IGF1 is the liver, but it is also produced in a wide variety of tissues and has endocrine and paracrine modes of action. The mature IGF1 peptide has A, B, C, and D domains with homology to insulin, and is highly conserved.2 It is produced as an inactive precursor, pre-pro-IGF1, with an additional carboxyterminal E region that plays an important role in the maturation of normal IGF1 peptide. This regulatory region is obtained by alternative splicing of the last two exons. IGF1 resides on the long arm of chromosome 12 (12q 22–24.1),3 and several molecular studies have demonstrated that the structure of this gene is very complex. The gene contains six exons, which extend over more than 85 kb on chromosomal DNA. For human IGF1, two potential primary translation products exist: IGF1A and IGF1B, with sizes of 153 and 195 amino acids respectively. The two precursors are synthesised from distinct messenger RNAs produced by alternative splicing of the primary transcript. IGF1A mRNA contains exons 1, 2, 3, 4, and 6 of the human IGF1 gene while IGF1B is encoded by exons 1, 2, 3, 4, and 5. It has been speculated that IGF1B plays the major role during intrauterine growth, while the same function during postnatal growth is taken over by IGF1A.4 Recent studies have focused attention on the genetic causes of growth alterations. Mutations involving the molecular structure of GH5 or the function of …

Phenylketonuria (PKU) is an autosomal recessive disease caused by the deficiency of a liver-specific enzyme, phenylalanine hydroxylase (PAH). The pattern of PAH mutations in Mediterranean populations appears to be different from that observed in northern Europe and Asia. Our aim was to study the molecular basis of PKU in Campania and Calabria, two regions of southern Italy. We studied 99 unrelated alleles, detecting 75.8% of the mutations. Our results show that 57% of all the PKU alleles are caused by three different mutations: IVS10nt-546, R261Q and L48S, which display significant differences in their relative distribution across Italy. A novel mutation, a G-to-T transversion at the codon 257 (G257C), was also identified. This mutation results in a Gly-to-Cys change in the catalytic domain of the protein.

The carbonic anhydrase II (CA II) deficiency syndrome is an autosomal recessive disorder that produces osteopetrosis, renal tubular acidosis, and cerebral calcification. Other features include developmental delay, short stature, cognitive defects, and a history of multiple fractures by adolescence. With one exception, all patients with osteopetrosis and renal tubular acidosis examined have proven to have CA II deficiency. All CA II-deficient patients analyzed have been found to have mutations in the CA2 gene. Previously, we used single strand conformational (SSCP) analysis to identify exons to be sequenced from CA II-deficient patients. In this report, we amplified all seven exons by PCR from genomic DNA and directly sequenced the amplified products. Application of this method allowed identification of eleven new mutations in 21 patients referred for confirmation of the diagnosis of CA II deficiency. These mutations were scattered over the genome from exon 2 to 7. In two opportunities for prenatal diagnosis, one from cultured amniocytes and one from chorionic villus biopsy, we demonstrated the general utility of the direct sequencing method for prenatal DNA diagnosis. These studies expand our knowledge of the heterogeneity in mutations underlying the CA II deficiency syndrome.

Background: Osteopetrosis is a rare genetic disorder characterized by increased bone density due to a defective osteoclast’s bone resorption. Three clinical forms can be identified based on severity, age of onset and inheritance: the dominant benign form (ADO), the intermediate form (IRO) and the recessive severe form (ARO). Several genes have been involved in the pathogenesis of these different types of osteopetrosis. Many experimental evidences point out on a specific role for CLCN7, the gene encoding the chloride channel protein subunit alfa and for TCIRG1, the gene encoding an osteoclast specific subunit of the vacuolar proton pump. Mutations in CLCN7 gene have been associated to the complete spectrum of osteopetrosis ranging from ARO t oI RO and even to ADO type II. On the other hand, mutations in TCIRG1 gene account for more than 50% of cases of ARO. It is then evident that the malignant osteopetrosis is characterized by a great molecular and clinical heterogeneity often making the final diagnosis difficult to achieve. Methods: We performed a complete clinical, biochemical and molecular analysis by PCR and direct sequencing, of a novel case of osteopetrosis with inconsistent clinical phenotype. Results: The patient, who cannot be ascribed to any of the ADO, ARO or IRO groups, carried two novel mutations in compound heterozygosis in the CLCN7 gene. The first was the missense mutation c. 948C > T on exon 10 that produces an Arg to Cys change, while the second was the IVS11 + 5G > A splicing mutation that resides on the donor splice site of intron 11 and distrupts the canonical splice site. Conclusion: Our data a) Demonstrate that the unusual clinical presentation observed in our patient with a mild clinical onset evolving towards a more serious clinical picture, is associated to two novel mutations on CLCN7 gene. b) Support the already described clinical and molecular heterogeneity of the malignant osteopetrosis c) Suggest that, performing a molecular diagnosis of osteopetrosis with inconsistent clinical presentation these two novel mutations have to be first considered.