Carmine Ungaro

A novel Angiogenin gene mutation in a sporadic patient with amyotrophic lateral sclerosis from southern Italy

Mutations in the Angiogenin gene (ANG) linked to 14q11.2 have been recently discovered to be associated with Amyotrophic Lateral Sclerosis (ALS) in Irish and Scottish populations. In our study we investigated the role of ANG gene in ALS patients from southern Italy. We found a novel mutation in the signal peptide of the ANG gene in a sporadic patient with ALS (SALS). The molecular analysis of the ANG gene also demonstrated an allelic association with the rs11701 single nucleotide polymorphism (SNP) in familial ALS (FALS) but not in SALS patients. Our finding supports the evidence that the ANG gene is involved in ALS.

Amyotrophic lateral sclerosis: a new missense mutation in the SOD1 gene

Copper-zinc superoxide dismutase-1 (SOD1) is the second most common mutated gene in amyotrophic lateral sclerosis (ALS). To date more than 150 missense mutations of SOD1 have been reported. The objective of this study was to describe a novel SOD1 mutation and its phenotypic expression. We describe a 74-year-old Caucasian man who began to complain of progressive weakness and atrophy of the right hand and over 10 months developed a severe tetraparesis, with atrophies of upper and lower limbs and neck muscles, dysphagia, and dyspnea that led to percutaneous endoscopic gastrostomy and tracheotomy. A diagnosis of ALS was made. Genetic analysis identified a heterozygous mutation in exon 4 of SOD1 that results in the amino acid substitution from arginine to cysteine at position 115 (p.R115C). We identified a novel pathogenic SOD1 mutation in a patient with a very rapid disease progression and aggressive phenotype providing additional information on the wide range of SOD1 mutations in apparently sporadic ALS and confirming the possibility of a strong genotype-phenotype correlation for distinct SOD1 mutations.

Mutation analysis of the SPG4 gene in Italian patients with pure and complicated forms of spastic paraplegia

Mutations in the SPG4 gene are the most common causes of hereditary spastic paraplegia (HSP) accounting for up to 40% of autosomal dominant (AD) forms and 12-18% of sporadic cases. The phenotype associated with HSP due to mutations in the SPG4 gene tends to be pure. There is increasing evidence, however, of patients with complicated forms of spastic paraplegia in which SPG4 mutations were identified. A cohort of 38 unrelated Italian patients with spastic paraplegia, of which 24 had a clear dominant inheritance and 14 were apparently sporadic, were screened for mutations in the SPG4 gene. We identified 11 different mutations, six of which were novel (p.Glu143GlyfsX8, p.Tyr415X, p.Asp548Asn, c.1656_1664delinsTGACCT, c.1688-3C>G and c.*2G>T) and two exon deletions previously reported. The overall rate of SPG4 gene mutation in our patients was 36.8% (14/38); in AD-HSP we observed a mutation frequency of 45.8% (11/24), in sporadic cases the frequency was 21.4% (3/14). Furthermore, we found a mutational rate of 22.2% (2/9) and 41.4% (12/29) in the complicated and pure forms, respectively. The results underlie the importance of genetic testing in all affected individuals.

CADASIL: Extended polymorphisms and mutational analysis of the NOTCH3 gene

CADASIL is a cerebrovascular disease caused by mutations in the NOTCH3 gene. Most mutations result in a gain or loss of cysteine residue in one of the 34 epidermal growth factor‐like repeats in the extracellular domain of the Notch3 protein, thus sparing the number of cysteine residues. To date, more than 130 different mutations in the NOTCH3 gene have been reported in CADASIL patients, of which 95% are missense point mutations. Many polymorphisms have also been identified in the NOTCH3 coding sequence, some of them leading to amino acid substitutions. The aim of the present study was to analyze the NOTCH3 gene in a large group of patients affected by leukoencephalopathy and to investigate the presence of genetic variants. The molecular analysis revealed several nucleotide alterations. In particular, we identified 20 different mutations, 22 polymorphisms, and 8 genetic variants of unknown pathological significance never reported previously. We hope that this NOTCH3 gene mutational analysis, performed in such a significant number of unrelated and related patients affected by leukoencephalopathy, will help in molecular screening for the NOTCH3 gene, thus contributing to enlargement of the NOTCH3 gene variation database.

A novel mutation in the X‐linked cyclin‐dependent kinase‐like 5 (CDKL5) gene associated with a severe Rett phenotype

Mutations in the X‐linked cyclin‐dependent kinase‐like 5 (CDKL5) gene have recently been reported in patients with severe neurodevelopmental disorder characterized by early‐onset seizures, infantile spasms, severe psychomotor impairment and very recently, in patients with Rett syndrome (RTT)‐like phenotype. Although the involvement of CDKL5 in specific biological pathways and its neurodevelopmental role have not been completely elucidated, the CDKL5 appears to be physiologically related to the MECP2 gene. Here we report on the clinical and CDKL5 molecular investigation in a very unusual RTT case, with severe, early‐neurological involvement in which we have shown in a previous report, a novel P388S MECP2 mutation [Conforti et al. (2003); Am J Med Genet A 117A: 184–187]. The patient has had severe psychomotor delay since the first month of life and infantile spasms since age 5 months. Moreover, at age 5 years the patient suddenly presented with renal failure. The severe pattern of symptoms in our patient, similar to a CDKL5 phenotype, prompted us to perform an analysis of the CDKL5, which revealed a novel missense mutation never previously described. The X‐inactivation assay was non‐informative. In conclusion, this report reinforces the observation that the CDKL5 phenotype overlaps with RTT and that CDKL5 analysis is recommended in patients with a seizure disorder commencing during the first months of life.

TARDBP gene mutations in south Italian patients with amyotrophic lateral sclerosis

TAR-DNA-binding protein 43 (TDP-43) has recently been identified as the major pathological protein in abnormal inclusions in neurons and glial cells in sporadic amyotrophic lateral sclerosis (SALS) and SOD1 negative familial cases with amyotrophic lateral sclerosis (FALS). TDP-43 is evolutionarily conserved, consisting of two RNA recognition motifs and a glycine-rich C-terminal domain. It is involved in the regulation of expression and splicing, and in other cellular processes such as microRNA biogenesis, apoptosis and cell division.1 2 Starting in early 2008, dominant mutations in TARDBP gene have been reported by several groups as a primary cause of ALS. To date, a total of 30 mutations of TARDBP have been reported not only in SOD1 -negative FALS cases (∼3%) but also in SALS cases (∼1.5%). All but one of the mutations identified (D169G) reside in exon 6 of the TARDBP gene, which encodes for the C-terminal glycine-rich domain of TDP-43. All of these mutations are dominantly inherited missense changes with the exception of a truncating mutation (Y374X) at the extreme C terminus of the protein.3 In this study, in order to investigate the presence and frequency of TARDBP mutations in a cohort of 310 south Italian patients affected by ALS, we performed a mutational screening of the exon 4 and exon 6 of the gene in SOD1 -negative FALS and SALS patients. …

A novel point mutation in PMP22 gene in an Italian family with hereditary neuropathy with liability to pressure palsies.

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant inherited disorder characterized by recurrent sensory or motor dysfunction. In 85% of HNPP cases the genetic defect is a 1.4 Mb deletion on chromosome 17p11.2, encompassing the PMP22 gene. Point mutations in the PMP22 gene responsible for HNPP phenotypes are rare. We investigated a 17-years-old girl who led to our detecting a novel mutation in PMP22 gene. The mutation was also detected in her father and corresponded to a deletion of one tymidine at position 11 in exon2 (c.11delT). This novel mutation creates a shift on the reading frame starting at codon 4 and leads to the introduction of a premature stop at codon 6.

Novel spastin (SPG4) mutations in Italian patients with hereditary spastic paraplegia.

Spastic paraplegia type 4 is caused by mutations in the gene that encodes spastin (SPG4), a member of the AAA protein family. A cohort of 34 unrelated Italian patients with pure spastic paraplegia, of which 18 displayed autosomal dominant inheritance and 16 were apparently sporadic, were screened for mutations in the SPG4 gene by denaturing high performance liquid chromatography. We identified a previously reported mutation in a sporadic patient with pure hereditary spastic paraplegia. We also identified eight unrelated patients with pure autosomal dominant hereditary spastic paraplegia carrying five novel mutations in the SPG4 gene (one missense mutation, c.1304 C>T; one nonsense mutation, c.807C>A; two frameshift mutations, c.1281dupT, c.1514_1515insATA; and one splicing mutation, c.1322-2A>C). The frequency for SPG4 mutations detected in autosomal dominant hereditary spastic paraplegia was 44.4%. This study contributes to expand the spectrum of SPG4 mutations in Italian population.

First evidence of a pathogenic insertion in the NOTCH3 gene causing CADASIL

CADASIL (OMIM 125310) is an increasingly recognised adult-onset autosomal-dominant vascular disease that is characterised by recurrent transient ischaemic attacks and strokes (43% of patients), vascular dementia (6%), migraine with aura (40% of patients) and psychiatric disturbances (9% of patients); epilepsy has been reported in 2–10% of subjects.1 All patients revealed prominent signal abnormalities on brain magnetic resonance imaging (MRI)—leukoencephalopathy on T2- and small subcortical infarcts on T1-weighted images.2 The pathological hallmark of CADASIL is a non-amyloid and non-arteriosclerotic angiopathy, which predominantly affects the small penetrating brain arteries. Vascular lesions are characterised by degeneration and loss of smooth-muscle cells and by the presence of granular osmiophilic material (GOM) accumulating within the smooth-muscle-cell basement membrane and the surrounding extracellular matrix. Examination of several peripheral organs revealed vessel changes, including the presence of GOM deposits, providing evidence that CADASIL is a systemic arteriopathy.3 It has been reported that CADASIL is caused by single missense mutations, small in-frame deletions or splice-site mutations in the NOTCH3 gene encoding a transmembrane receptor (http://www.hgmd.cf.ac.uk/ac/gene.php?gene = NOTCH3). Almost all previously reported mutations resulted in an odd number of cysteine residues within one of the 34 epidermal growth factor (EGF)-like repeats in the …

A novel locus for dHMN with pyramidal features maps to chromosome 4q34.3-q35.2

The distal hereditary motor neuropathy (dHMN) is a rare genetically and clinically heterogeneous disorder characterized by weakness and wasting of distal limb muscles in absence of overt sensory abnormalities. Recently, pyramidal signs have been also described in some patients with dominant or recessive dHMN, and two different loci have been identified in families affected by dHMN complicated with pyramidal dysfunction. We investigated an Italian family affected by an autosomal dominant dHMN complicated by pyramidal signs in order to map a new gene locus. The disease maps to a novel locus in a 26‐cM region flanked by D4S1552 and D4S2930 on chromosome 4q34.3‐35.2. Three candidate genes (SNX25, CASP3 and TUBB4Q) located in the critical region were screened for the presence of mutations by heteroduplex analysis. No mutations have been detected in the analyzed genes. In conclusion, the new private genetic locus we reported further confirms the wide heterogeneity of dHMN.