Clinical and molecular report of novel GALC mutations in Moroccan patient with Krabbe disease: case report.

BACKGROUND: Krabbe disease (KD) or globoid cell leukodystrophy is an autosomal recessive lysosomal disorder, which affects metabolic and neurologic systems. This pathology has different forms. Infantile onset is about 85% to 90% of individuals with Krabbe disease. Disorder's onset is characterized, in early childhood, by hyperirritability, psychomotor deterioration associated to episodes of fever. To date, all reported cases have been attributed to mutations in galactosylceramidase gene (GALC gene) that encodes an enzyme which degrades galactosyl-sphingolipids (galactosylceramide, psychosine), essential in myelin production. A child compounded with two new mutations in the GALC gene was detected. CASE PRESENTATION: An eleven month old male child of Moroccan origin presented to our genetic consultation with severe symptoms that included hypotonia, fever, vision loss and feeding difficulties. He was suffering from the 4th month of life. Krabbe disease was suspected. Galactocerebrosidase deficiency was confirmed by biochemical analysis. DNA sequencing revealed a novel heterozygous compound mutation in GALC gene. The child was compounded with two mutations c.860G > A; p.Cys287Tyr and c.1622G > A; p.Trp541*. CONCLUSION: These new mutations could affect GALC structure and therefore its function. The identification of these mutations and their associated phenotypes are important to predict the prognosis and to confer to families an adequate genetic counseling.

Novel optineurin mutations in patients with familial and sporadic amyotrophic lateral sclerosis.

BACKGROUND: Optineurin (OPTN), a causative gene of hereditary primary open-angle glaucoma, has been recently associated with amyotrophic lateral sclerosis (ALS) with mainly autosomal recessive, but also dominant, traits. To further define the contribution of OPTN gene in ALS, we performed a mutational screening in a large cohort of Italian patients. METHODS: A group of 274 ALS patients, including 161 familial (FALS) and 113 sporadic (SALS) cases, were screened for OPTN mutations by direct sequencing of its coding sequence. All patients fulfilled the El Escorial criteria for probable or definite ALS and were negative for mutations in SOD1, ANG, TARDBP and FUS/TLS genes. RESULTS: The genetic analysis revealed six novel variants in both FALS and SALS patients, all occurring in an heterozygous state. We identified three missense (c.844A→C p.T282P, c.941A→T p.Q314L, c.1670A→C p.K557T), one nonsense (c.67G→T p.G23X) and two intronic mutations (c.552+1delG, c.1401+4A→G). The intronic c.552+1delG variant determined a splicing defect as demonstrated by mRNA analysis. All mutations were absent in 280 Italian controls and over 6800 worldwide glaucoma patients and controls screened so far. The clinical phenotype of OPTN-mutated patients was heterogeneous for both age of onset and disease duration but characterised by lower-limb onset and prevalence of upper motor neuron signs. CONCLUSION: In this cohort, OPTN mutations were present both in FALS (2/161), accounting for 1.2% cases, and in SALS patients (4/113), thereby extending the spectrum of OPTN mutations associated with ALS. The study further supports the possible pathological role of optineurin protein in motor neuron disease.

High frequency of TARDBP gene mutations in Italian patients with amyotrophic lateral sclerosis.

Recent studies identified rare missense mutations in amyotrophic lateral sclerosis (ALS) patients in the TARDBP gene encoding TAR DNA binding protein (TDP)-43, the major protein of the ubiquitinated inclusions (UBIs) found in affected motor neurons (MNs). The aim of this study was to further define the spectrum of TARDBP mutations in a large cohort of 666 Italian ALS patients (125 familial and 541 sporadic cases). The entire coding region was sequenced in 281 patients, while in the remaining 385 cases only exon 6 was sequenced. In 18 patients, of which six are familial, we identified 12 different heterozygous missense mutations (nine novel) all locating to exon 6, which were absent in 771 matched controls. The c.1144G>A (p.A382T) variation was observed in seven patients, thus representing the most frequent TARDBP mutation in ALS. Analysis of microsatellites surrounding the TARDBP gene indicated that p.A382T was inherited from a common ancestor in 5 of the 7 patients. Altogether, the frequency of TARDBP gene mutations appears to be particularly high in Italian ALS patients compared to individuals of mainly Northern European origin (2.7% vs. 1%). Western blot analysis of lymphocyte extracts from two patients carrying the p.A382T and p.S393L TARDBP mutations showed the presence of lower molecular weight TDP-43 bands, which were more abundant than observed in healthy controls and patients negative for TARDBP mutations. In conclusion, this report contributes to the demonstration of the causative role of the TARDBP gene in ALS pathogenesis and indicates that mutations may affect the stability of the protein even in nonneuronal tissues.

FMR1 gene premutation is a frequent genetic cause of late-onset sporadic cerebellar ataxia.

In an Italian population of 275 unrelated men affected by adult-onset sporadic progressive cerebellar ataxia, the authors found six patients carrying an FMR1 gene premutation. Age at onset (range, 53 to 69 years) and clinical-neuropathologic findings were consistent with the fragile-X tremor ataxia syndrome (FXTAS), although tremor was not as common as previously described. FXTAS accounted for 4.2% of the cases diagnosed at >50 years, suggesting that it is a frequent genetic cause of late-onset sporadic ataxia.

Ataxia with isolated vitamin E deficiency: neurological phenotype, clinical follow-up and novel mutations in TTPA gene in Italian families.

Ataxia with vitamin E deficiency (AVED) is a rare autosomal recessive neurodegenerative disorder due to mutations in the alpha-tocopherol transfer protein (TTPA) gene on chromosome 8q13. AVED patients have progressive spinocerebellar symptoms and markedly reduced plasma levels of vitamin E. We studied neurological phenotype at diagnosis, and long-term effect of vitamin E supplementation in 16 patients from 12 Italian families. The most common mutations were the 744delA and 513insTT. Two novel TTPA mutations were identified: a severe truncating mutation (219insAT) in a homozygous patient, and a Gly246Arg missense mutation (G246R) in a compound heterozygous patient. The missense mutation was associated with a mild and slowly progressive form of the disease. Vitamin E supplementation therapy allowed a stabilization of the neurological conditions in most of the patients. However, development of spasticity and retinitis pigmentosa was noted in a few patients during therapy. Prompt genetic characterization of AVED patients may allow an effective early treatment and an adequate genetic counseling.

Superoxide dismutase gene mutations in Italian patients with familial and sporadic amyotrophic lateral sclerosis: identification of three novel missense mutations.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting motor neurons. The majority of the patients are sporadic cases (SALS), while 5-10% of the patients have a family history of ALS (familial ALS or FALS). Mutations in the gene coding for cytoplasmic Cu/Zn superoxide dismutase (SOD1) have been identified in about 20% of FALS cases. We found SOD1-gene mutations in five of 34 unrelated FALS, and in two of 44 SALS patients. Three FALS patients carried the previously described A4V (two cases) and L84F mutations (one case), while two FALS patients carried new missense mutations: a G12R substitution in exon 1, and a F45C substitution in exon 2, respectively. The newly identified mutations were both associated with a slowly progressive disease course. Two SALS patients carried the homozygous D90A and the heterozygous I113T mutation, respectively. In addition, in one SALS patient we identified an A95T amino acid substitution, that is apparently a non-pathogenic SOD1 variant. Our study increases the number of ALS-associated SOD1 gene mutations.

Atypical movement disorders in the early stages of Huntington's disease: clinical and genetic analysis.

Huntington's disease (HD) is notably difficult to diagnose in the early stages. One reason is that the early clinical manifestations of HD vary widely and sometimes have an atypical onset. In this paper we primarily sought information on affected patients who initially presented with movement disorders other than chorea. We also investigated atypical motor presentations in relation to triplet CAG expansions. After reviewing the clinical records of two neurological centres, we identified patients with a final, documented diagnosis of HD and selected for study 205 patients according to their onset of motor manifestations. CAG repeats were analysed. Of the 205 patients studied, 15 had atypical motor symptoms at onset. In this group we identified three types of initial clinical manifestations other than chorea: parkinsonism, ataxia and dystonia. We conclude that HD patients may have different motor manifestations at the initiation of the illness. Patients with atypical movement disorders in the early stages have larger CAG expansions and an earlier age at onset than HD patients with typical onset chorea.

Phenotypic manifestations associated with CAG-repeat expansion in the androgen receptor gene in male patients and heterozygous females: a clinical and molecular study of 30 families.

Spinal and bulbar muscular atrophy (Kennedy disease) is an adult form of X-linked motor neuron disease caused by the expansion of a polymorphic CAG-repeat sequence in the first exon of the androgen receptor gene. We studied clinical and molecular features of 36 patients and 19 heterozygous females. Phenotypic manifestations and disease severity broadly varied among our spinal and bulbar muscular atrophy patients. The size of CAG expansion significantly influences the age of disease onset, but neither clinical features nor disease severity. The majority of carrier women presented signs of chronic denervation at neurophysiological examination and, in three cases, low-amplitude sensory action potentials were recorded. Notably, a few women developed mild signs of bulbar motor neuron impairment later in life. The identification of a large number of patients by the use of the molecular test further supports the hypothesis that Kennedy disease had been previously underdiagnosed, probably because of the great variability of clinical presentation. Although an early diagnosis may not be crucial for treatment, given the lack of effective therapy, the molecular testing can be of great relevance for disease prognosis and genetic counseling.

Family and molecular data for a fine analysis of age at onset in Huntington disease.

We analyzed the data on age at onset and CAG size of 319 patients clinically diagnosed with Huntington disease (HD) and 86 presymptomatic subjects recorded by four Italian Centers over the last 14 years. To overcome the problem of different CAG numbers found in each subject, also in the same family, the data were analyzed in terms of deviations from the average exponential relationship between onset and CAG number. The subject's year of birth was also considered to quantify possible sampling biases. Observations between relatives were compared with those of the whole group. The deviations were equal, on average, in subjects who inherited their HD gene from their fathers or mothers. Overall, our data argue in favor of a greater similarity across the same generation than across successive generations. In particular, an excess of parents with later than expected age of onset was observed, paralleled by a CAG-independent anticipation of onset in parent-child transmissions. These results can be interpreted in terms of a shared environment determining similar departures from the average CAG-onset relationship but also of a systematic effect that differentiates the two generations here examined.

Clinical and molecular studies of 73 Italian families with autosomal dominant cerebellar ataxia type I: SCA1 and SCA2 are the most common genotypes.

We clinically and genetically evaluated 73 Italian families with autosomal dominant cerebellar ataxia (ADCA) type I. Spinocerebellar ataxia (SCA) type 1 was the most common genotype (SCA1), accounting for 41% of cases (30 families), SCA2 was slightly less frequent (29%, 21 families), and the remaining families were negative for the SCA1, SCA2, and SCA3 mutations. Among the positively genotyped families, SCA1 was found most frequently in families from northern Italy (50%), while SCA2 was the most common mutation in families from the southern part of the country (56%). Slow saccades and decreased deep tendon reflexes were observed significantly more frequently in SCA2 patients, while increased deep tendon reflexes and nystagmus were more common in SCA1. In SCA1 and SCA2 families there was a significant inverse correlation between expansion size and age at onset. Analysis of triplet repeat numbers in parent-offspring pairs showed greater meiotic instability, which was associated with an earlier onset of the disease in SCA2 families than in SCA1 families.

Clinical and molecular findings in the first identified Italian family with dentatorubral-pallidoluysian atrophy.

OBJECTIVES: Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare autosomal dominant neurodegenerative disorder mostly observed in Japan, rarely reported in American and North European populations. The aim of this study is to characterize the clinical and molecular features of the first identified Italian DRPLA family. PATIENTS AND METHODS: We describe a 33-year-old female presenting with ataxia, intellectual decline, epilepsy, and choreoathetosis with an adult age onset. Genomic DNA was isolated from peripheral blood lymphocytes of the patient and of her healthy family members following standard procedures. Molecular tests were performed including genetic analysis for SCA1, 2, and 3 (spinocerebellar ataxias), Huntington's disease (HD) and DRPLA, due to a possible overlapping in clinical presentation. RESULTS: Molecular analysis revealed in our patient the presence of a pathological CAG expansion within the DRPLA gene. We have also documented the presence of a smaller CAG expansion in her apparently healthy brother, excluding the possibility of a de novo mutation. CONCLUSION: We conclude that both siblings may have inherited the molecular lesion from their deceased father, the mother being normal at molecular evaluation. Our kindred and a previously reported family from the island of Malta suggest that hereditary DRPLA may also be present in the Mediterranean area.

Unusual EEG pattern linked to chromosome 3p in a family with idiopathic generalized epilepsy.

OBJECTIVE: To map the gene causing an unusual EEG pattern of delta bursts that appears to segregate as an autosomal dominant trait in an Italian family. The EEG pattern was observed in four family members affected by idiopathic generalized epilepsy (IGE) and in six other clinically unaffected members. METHODS: All available family members underwent clinical and EEG examination. DNA samples were obtained and used to perform a whole-genome scan with 270 microsatellite markers. After the first linked marker was identified, 12 additional markers in the same chromosomal region were tested to confirm linkage and define a candidate interval. RESULTS: The gene responsible for the EEG trait was mapped to an 11-cM interval on the proximal short arm of chromosome 3 (3p14.2-p12.1). CONCLUSION: In this family, a characteristic EEG activity is due to the effect of a single gene on chromosome 3p. A gene encoding a Ca2+ channel subunit maps in the interval and is a potential candidate for the trait. The clinical expression of epilepsy in four family members may reflect the interaction of additional genes, though environmental or other factors cannot be excluded.

Clinical and genetic study of a family with spinocerebellar ataxia type 1 (SCA1) and beta-thalassemia.

We report a family affected by autosomal dominant ataxia, in which numerous members also showed microcytosis. Genetic analysis demonstrated a CAG expansion in the SCA1 locus in five members, while all subjects with microcytosis revealed a C-T substitution at codon 39 of the beta-globin gene. A pure cerebellar syndrome with prominent gait ataxia characterized the first stages of the neurological disease. The fully developed disease included additional clinical findings such as dysarthria and dysphagia, and instrumental signs of axonal involvement of the peripheral nerves. Ophthalmoplegia was not observed. The coexistence of hereditary spinocerebellar degeneration and erythropathies or hemoglobinopathies has been previously described. We discuss the possible linkages between these two pathologies.

Very late onset Friedreich's ataxia without cardiomyopathy is associated with limited GAA expansion in the X25 gene.

Molecular analysis of spinocerebellar ataxias revealed a pathologic GAA expansion in the gene encoding frataxin in six adult patients from three families. These patients, carrying expanded alleles in the low-range size, had an exceptionally late onset and lacked cardiomyopathy, pointing to phenotypic variability of Friedreich's ataxia. Both mitotic and gametic instability of the expanded triplet repeat were present in these families.

Phenotypic variability in Friedreich ataxia: role of the associated GAA triplet repeat expansion.

We studied genotype-phenotype correlations in a group of 100 patients with typical Friedreich ataxia (FRDA), and in three groups of patients with atypical clinical presentations, including 44 Acadian FRDA, 8 late-onset FRDA (LOFA), and 6 FRDA with retained reflexes (FARR). All patients, except 3 with typical FRDA, carried two copies of the FRDA-associated GAA triplet repeat expansion. Overall, the phenotypic spectrum of FRDA appeared to be wider than defined by the currently used diagnostic criteria. Our study indicated the existence of several sources of variability in FRDA. Patients with larger GAA expansions tended to have earlier onset and were more likely to show additional manifestations of the disease. Mitotic instability of the expanded GAA repeats may partially account for the limited degree of correlation between expansion sizes as determined in lymphocytes and clinical parameters. Some clinical variants associated with specific FRDA haplotypes, such as Acadian FRDA and FARR, turned out to be unrelated to expansion sizes. No polymorphism in the frataxin coding sequence could be associated with these clinical variants.

Kennedy's disease: clinical and molecular study of two Italian families.

Kennedy's disease, or spinal and bulbar muscular atrophy (SBMA), is a rare X-linked motoneuron disorder with variable signs of androgen insensitivity. It is associated with the expansion of a trinucleotide CAG repeat within the androgen receptor (AR) gene. We here report our clinical and molecular findings in two Italian families with Kennedy's disease. The increased size of the CAG repeat was demonstrated in four affected males and seven carrier females.

Mapping of genes predisposing to idiopathic generalized epilepsy.

Idiopathic generalized epilepsy (IGE) is characterized by recurring generalized seizures in the absence of detectable brain lesions and/or metabolic abnormalities. Twin and family studies suggest that genetic factors play a key part in IGE. A multilocus model appears to best fit the observed inheritance patterns. Mapping of IGE-related genes has been previously attempted using parametric methods, with conflicting results. In particular, recent evidence argues both for and against a chromosome 6p locus (EJM1) for juvenile myoclonic epilepsy, a subtype of IGE. We have approached the problem of mapping IGE loci using non-parametric methods, which have recently been successful for other complex diseases. No evidence for linkage to chromosome 6p was obtained. However, we obtained evidence for involvement of a locus at chromosome 8q24, close to the marker D8S256. The same 8q24 region was previously implicated in families with benign neonatal familial convulsions (BNFC), a generalized epilepsy syndrome that is inherited as a simple dominant mendelian trait. There is an apparent conserved syntenic group of genes in human 8q24 and a region of mouse chromosome 15, which harbors the stargazer (stg) locus. Homozygous mutant mice at the stg locus show a form of generalized epilepsy that resembles human absence epilepsy. Our findings may have implications for a locus on 8q24 predisposing to IGE.