Gaucher disease (GD), the most prevalent lysosomal storage disease characterized by a remarkable degree of clinical variability, results from deleterious mutations in the glucocerebrosidase gene (GBA). In this paper we report the molecular characterization of 144 unrelated Italian GD patients with the three types of the disease. The allelic frequencies of Italians are reported and the mutation profile is analyzed. Besides the common N370S, L444P, RecNciI, G202R, IVS2+1G>A, D409H, F213I mutations, the different molecular strategies, used for the mutation detection, identified the rare N107L, R131C, R170C, R170P, N188S, S196P, R285C, R285H, W312C, D399N, A446P, IVS10-1G>A, Rec∆55, total gene deletion, as well as 12 mutant alleles that were exclusively present in the Italian population until now: the previously reported R353G, N370S+S488P mosaicism, IVS8(-11delC)-14T>A), Rec I, Y418C, and the seven novel alleles D127X, P159T, V214X, T231R, L354X, H451R, and G202R+M361I. The wide phenotypic differences observed within the genotypic groups as well as between siblings implicate a significant contribution of other modifying genetic and/or non-genetic factors and claim a comprehensive valuation of the patient including clinical., biochemical and molecular investigations for prognosis, appropriate interventive therapy and reliable genetic counseling.

Mucopolysaccharidosis type II (MPS2, or Hunter syndrome), rare X-linked lysosomal storage disorder, results from deleterious mutations in the iduronate-2-sulfatase (IDS) gene. We report here the mutational analysis of a total of 40 unrelated Italian MPS II patients ranging from mild to severe phenotype. We are able to assign the genotype to 29 of them (72.5%), identifying 22 different mutations, five of which are unpublished (c.533delTT, W12X, N265I, c.1131-1142del, c.1131-1305del). A total of 55.2% of the molecularly characterised patients resulted from missense mutations, 20.7% from nonsense mutations, and another 13.8% of patients from small deletions (<20pb) or splice mutations, whereas 10.3% of the cases carried major structural alterations such as large deletion and rearrangements. The results reported here support the evidence of the mutational heterogeneity of the IDS gene as well as the difficulty to correlate genotype and phenotype in the patients with MPSII. However, the molecular characterisation of the patients is advantageous, making the carrier detection feasible for the females in the family at risk and improving the reliability of prenatal diagnosis techniques. Moreover, it provides a good foundation for therapeutic strategies.

ASAH1 gene encodes for acid ceramidase that is involved in the degradation of ceramide into sphingosine and free fatty acids within lysosomes. ASAH1 variants cause both the severe and early-onset Farber disease and rare cases of spinal muscular atrophy (SMA) with progressive myoclonic epilepsy (SMA-PME), phenotypically characterized by childhood onset of proximal muscle weakness and atrophy due to spinal motor neuron degeneration followed by occurrence of severe and intractable myoclonic seizures and death in the teenage years. We studied two subjects, a 30-year-old pregnant woman and her 17-year-old sister, affected with a very slowly progressive non-5q SMA since childhood. No history of seizures or myoclonus has been reported and EEG was unremarkable. The molecular study of ASAH1 gene showed the presence of the homozygote nucleotide variation c.124A4G (r.124a4g) that causes the amino acid substitution p.Thr42Ala. Biochemical evaluation of cultured fibroblasts showed both reduction in ceramidase activity and accumulation of ceramide compared with the normal control. This study describes for the first time the association between ASAH1 variants and an adult SMA phenotype with no myoclonic epilepsy nor death in early age, thus expanding the phenotypic spectrum of ASAH1-related SMA. ASAH1 molecular analysis should be considered in the diagnostic testing of non-5q adult SMA patients.

; Web site: http://www.gaslini.org/labdppm.htm Communicated by Robert DesnickNiemann-Pick disease (NPD) results from the deficiency of lysosomal acid sphingomyelinase (SMPD1). To date, out of more than 70-disease associated alleles only a few of them have a significant frequency in various ethnic groups. In contrast, the remainder of the mutations are rare or private. In this paper we report the molecular characterization of an Italian series consisting of twenty-five NPD patients with the severe neurodegenerative A phenotype. Mutation detection identified a total of nineteen different mutations, including 14 novel mutations and five previously reported lesions. The known p.P189fs and the novel p.T542fs were the most frequent mutations accounting for 34% and 18% of the alleles, respectively. Screening the alleles for the three common polymorphisms revealed the variant c.1516G>A (exon 6) and the repeat in exon 1, but not the variant c.965C>T (exon 2). In absence of frequent mutations, the prognostic value of genotyping is limited. However, new genotype/phenotype correlations were observed for this disorder that could in the future facilitate genetic counseling and guide selection of patients for therapy.