Inferring biallelism of two FSH receptor mutations associated with spontaneous ovarian hyperstimulation syndrome by evaluating FSH, LH and HCG cross-activity

RESEARCH QUESTION

What is the cumulative effect of two follicle-stimulating hormone receptor (FSHR) mutations in spontaneous ovarian hyperstimulation syndrome (sOHSS) pathogenesis? Are these mutations in the mono- or biallelic state?

DESIGN

Two FSHR mutations were found in a pregnant patient affected by sOHSS with no predisposing conditions. While the p.Asn106His mutation is novel, the p.Ser128Tyr mutation has been associated with sOHSS previously. The patient's FSHR gene was analysed by Sanger sequencing, and FSHR cDNAs carrying a single or both point mutations were created by mutagenesis in vitro. cAMP activation by recombinant FSH, luteinizing hormone (LH), human chorionic gonadotropin (HCG) and thyroid-stimulating hormone (TSH) was evaluated in transfected HEK293 cells by bioluminescence resonance energy transfer.

RESULTS

All mutations decreased the 50% effective concentration of FSH calculated for cAMP (P < 0.05, n = 6), resulting in two- to 10-fold lower ligand potency. TSH failed to induce an FSHR-mediated increase in intracellular cAMP, while LH was approximately four-fold more potent than HCG in p.Ser128Tyr FSHR-expressing HEK293 cells despite lower cAMP plateau levels (P < 0.05, n = 5). The p.Ser128Tyr FSHR mutation was found to be responsible for an LH-/HCG-induced increase in cAMP when it was in the biallelic heterozygous state with p.Asn106His, but no increase in cAMP was induced in the monoallelic state.

CONCLUSION

In-vitro data support that, in pregnant patients with sOHSS, the two FSHR mutations have an opposing effect on the pathogenesis of sOHSS and are in the biallelic heterozygous form, allowing HCG to induce a p.Ser128Tyr FSHR-mediated increase in cAMP.

Analysis of the Rhodopsin and Peripherin/Rds Gene in Two Families with Pattern Dystrophy of the Retinal Pigment Epithelium

Mutations of the peripherin/retinal degeneration slow (RDS) gene have been reported in autosomal dominant retinitis pigmentosa and variable forms of pattern dystrophy of the retinal pigment epithelium. We screened the rhodopsin and the peripherin/RDS gene in the members of two families who presented the clinical features of pattern dystrophy of the retinal pigment epithelium transmitted as an autosomal dominant trait. No migration patterns were detected in single strand conformation polymorphism or hydrolink gels. Both the rhodopsin and the peripherin/RDS gene were normal in one family. In the second, the proband had a normal rhodopsin gene and, although he passed a different haplotype to each of his affected daughters, there was no linkage with the peripherin/RDS gene. The origin of the retinal disturbance in our two pedigrees must therefore be sought, if indeed DNA is involved, elsewhere in the genome. Our findings provide additional evidence that pattern dystrophies of the retinal pigment epithelium may be pathogenically related in spite of different etiological origins. The genetic polymorphism can probably account for the wide range of phenotypes.

Copy number variants analysis in a cohort of isolated and syndromic developmental delay/intellectual disability reveals novel genomic disorders, position effects and candidate disease genes

BACKGROUND

Array-comparative genomic hybridization (array-CGH) is a widely used technique to detect copy number variants (CNVs) associated with developmental delay/intellectual disability (DD/ID).

AIMS

Identification of genomic disorders in DD/ID.

MATERIALS AND METHODS

We performed a comprehensive array-CGH investigation of 1,015 consecutive cases with DD/ID and combined literature mining, genetic evidence, evolutionary constraint scores, and functional information in order to assess the pathogenicity of the CNVs.

RESULTS

We identified non-benign CNVs in 29% of patients. Amongst the pathogenic variants (11%), detected with a yield consistent with the literature, we found rare genomic disorders and CNVs spanning known disease genes. We further identified and discussed 51 cases with likely pathogenic CNVs spanning novel candidate genes, including genes encoding synaptic components and/or proteins involved in corticogenesis. Additionally, we identified two deletions spanning potential Topological Associated Domain (TAD) boundaries probably affecting the regulatory landscape.

DISCUSSION AND CONCLUSION

We show how phenotypic and genetic analyses of array-CGH data allow unraveling complex cases, identifying rare disease genes, and revealing unexpected position effects.

Monocytes of patients with amyotrophic lateral sclerosis linked to gene mutations display altered TDP-43 subcellular distribution

AIMS

Cytoplasmic accumulation of the nuclear protein transactive response DNA-binding protein 43 (TDP-43) is an early determinant of motor neuron degeneration in most amyotrophic lateral sclerosis (ALS) cases. We previously disclosed this accumulation in circulating lymphomonocytes (CLM) of ALS patients with mutant TARDBP, the TDP-43-coding gene, as well as of a healthy individual carrying the parental TARDBP mutation. Here, we investigate TDP-43 subcellular localization in CLM and in the constituent cells, lymphocytes and monocytes, of patients with various ALS-linked mutant genes.

METHODS

TDP-43 subcellular localization was analysed with western immunoblotting and immunocytofluorescence in CLM of healthy controls (n = 10), patients with mutant TARDBP (n = 4, 1 homozygous), valosin-containing protein (VCP; n = 2), fused in sarcoma/translocated in liposarcoma (FUS; n = 2), Cu/Zn superoxide dismutase 1 (SOD1; n = 6), chromosome 9 open reading frame 72 (C9ORF72; n = 4), without mutations (n = 5) and neurologically unaffected subjects with mutant TARDBP (n = 2).

RESULTS

TDP-43 cytoplasmic accumulation was found (P < 0.05 vs. controls) in CLM of patients with mutant TARDBP or VCP, but not FUS, in line with TDP-43 subcellular localization described for motor neurons of corresponding groups. Accumulation also characterized CLM of the healthy individuals with mutant TARDBP and of some patients with mutant SOD1 or C9ORF72. In 5 patients, belonging to categories described to carry TDP-43 mislocalization in motor neurons (3 C9ORF72, 1 TARDBP and 1 without mutations), TDP-43 cytoplasmic accumulation was not detected in CLM or in lymphocytes but was in monocytes.

CONCLUSIONS

In ALS forms characterized by TDP-43 mislocalization in motor neurons, monocytes display this alteration, even when not manifest in CLM. Monocytes may be used to support diagnosis, as well as to identify subjects at risk, of ALS and to develop/monitor targeted treatments.

Array-Comparative Genomic Hybridization Analysis in Fetuses with Major Congenital Malformations Reveals that 24% of Cases Have Pathogenic Deletions/Duplications

Karyotyping and aCGH are routinely used to identify genetic determinants of major congenital malformations (MCMs) in fetal deaths or terminations of pregnancy after prenatal diagnosis. Pathogenic rearrangements are found with a variable rate of 9-39% for aCGH. We collected 33 fetuses, 9 with a single MCM and 24 with MCMs involving 2-4 organ systems. aCGH revealed copy number variants in 14 out of 33 cases (42%). Eight were classified as pathogenic which account for a detection rate of 24% (8/33) considering fetuses with 1 or more MCMs and 33% (8/24) taking into account fetuses with multiple malformations only. Three of the pathogenic variants were known microdeletion syndromes (22q11.21 deletion, central chromosome 22q11.21 deletion, and TAR syndrome) and 5 were large rearrangements, adding up to >11 Mb per subject and comprising strong phenotype-related genes. One of those was a de novo complex rearrangement, and the remaining 4 duplications and 2 deletions were 130-900 kb in size, containing 1-7 genes, and were classified as variants of unknown clinical significance. Our study confirms aCGH as a powerful technique to ascertain the genetic etiology of fetal major congenital malformations.

C9ORF72 intermediate repeat expansion in patients affected by atypical parkinsonian syndromes or Parkinson's disease complicated by psychosis or dementia in a Sardinian population

The hexanucleotide repeat expansion GGGGCC in the C9ORF72 gene larger than 30 repeats has been identified as a major genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Recent papers investigated the possible pathogenic role and associated clinical phenotypes of intermediate C9ORF72 repeat expansion ranging between 20 and 30 repeats. Some studies suggested its pathogenicity for typical Parkinson's disease (PD), atypical parkinsonian syndromes, FTD with/without parkinsonism, and ALS with/without parkinsonism or with/without dementia. In our study, we aimed to screen patients affected by atypical parkinsonian syndromes or PD complicated by psychosis or dementia for the presence of C9ORF72 repeat expansions, and in unrelated age- and sex-matched healthy controls. Consecutive unrelated patients with atypical parkinsonian syndromes and patients with PD complicated by psychosis or dementia were included in this study. Atypical parkinsonian syndromes were further divided into two groups: one with patients who met the criteria for the classic forms of atypical parkinsonism [multiple system atrophy (MSA), Lewy body disease (LBD), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD)] ;and patients who did not meet the above criteria, named non-classical atypical parkinsonism with or without dementia. Ninety-two unrelated patients (48 men, 44 women) were enrolled. None of the patients was found to be carriers of C9ORF72 repeat expansions with more than 30 repeats. Intermediate 20-30 repeat expansions were detected in four female patients (4.3 %). Three of them presented clinical features of atypical parkinsonian syndromes, two with non-classical atypical parkinsonism and dementia FTD-like, and one with non-classical atypical parkinsonism without dementia. The other patient presented clinical features of typical PD complicated by psychosis. Among 121 control subjects, none presented long or short expansion for the C9ORF72 gene. Our findings seem to support the hypothesis that the hexanucleotide expansions of C9ORF72 gene with intermediate repetitions between 20 and 29 repetitions could be associated with typical PD with psychosis or dementia and atypical parkinsonisms with dementia (non-classical atypical parkinsonism with dementia FTD-like) or without dementia (non-classical atypical parkinsonism upper MND-like), although the causal relationship is still unclear. In these latter patients, parkinsonism, more or less levodopa responsive, constituted the symptomatological central core at onset.

A genome-wide association study of myasthenia gravis

IMPORTANCE

Myasthenia gravis is a chronic, autoimmune, neuromuscular disease characterized by fluctuating weakness of voluntary muscle groups. Although genetic factors are known to play a role in this neuroimmunological condition, the genetic etiology underlying myasthenia gravis is not well understood.

OBJECTIVE

To identify genetic variants that alter susceptibility to myasthenia gravis, we performed a genome-wide association study.

DESIGN, SETTING, AND PARTICIPANTS

DNA was obtained from 1032 white individuals from North America diagnosed as having acetylcholine receptor antibody-positive myasthenia gravis and 1998 race/ethnicity-matched control individuals from January 2010 to January 2011. These samples were genotyped on Illumina OmniExpress single-nucleotide polymorphism arrays. An independent cohort of 423 Italian cases and 467 Italian control individuals were used for replication.

MAIN OUTCOMES AND MEASURES

We calculated P values for association between 8,114,394 genotyped and imputed variants across the genome and risk for developing myasthenia gravis using logistic regression modeling. A threshold P value of 5.0×10(-8) was set for genome-wide significance after Bonferroni correction for multiple testing.

RESULTS

In the overall case-control cohort, we identified association signals at CTLA4 (rs231770; P=3.98×10(-8); odds ratio, 1.37; 95% CI, 1.25-1.49), HLA-DQA1 (rs9271871; P=1.08×10(-8); odds ratio, 2.31; 95% CI, 2.02-2.60), and TNFRSF11A (rs4263037; P=1.60×10(-9); odds ratio, 1.41; 95% CI, 1.29-1.53). These findings replicated for CTLA4 and HLA-DQA1 in an independent cohort of Italian cases and control individuals. Further analysis revealed distinct, but overlapping, disease-associated loci for early- and late-onset forms of myasthenia gravis. In the late-onset cases, we identified 2 association peaks: one was located in TNFRSF11A (rs4263037; P=1.32×10(-12); odds ratio, 1.56; 95% CI, 1.44-1.68) and the other was detected in the major histocompatibility complex on chromosome 6p21 (HLA-DQA1; rs9271871; P=7.02×10(-18); odds ratio, 4.27; 95% CI, 3.92-4.62). Association within the major histocompatibility complex region was also observed in early-onset cases (HLA-DQA1; rs601006; P=2.52×10(-11); odds ratio, 4.0; 95% CI, 3.57-4.43), although the set of single-nucleotide polymorphisms was different from that implicated among late-onset cases.

CONCLUSIONS AND RELEVANCE

Our genetic data provide insights into aberrant cellular mechanisms responsible for this prototypical autoimmune disorder. They also suggest that clinical trials of immunomodulatory drugs related to CTLA4 and that are already Food and Drug Administration approved as therapies for other autoimmune diseases could be considered for patients with refractory disease.

ATXN2 is a modifier of phenotype in ALS patients of Sardinian ancestry

Intermediate-length CAG expansions (encoding 27-33 glutamines, polyQ) of the Ataxin2 (ATXN2) gene represent a risk factor for amyotrophic lateral sclerosis (ALS). Recently, it has been proposed that ≥31 CAG expansions may influence ALS phenotype. We assessed whether ATXN2 intermediate-length polyQ expansions influence ALS phenotype in a series of 375 patients of Sardinian ancestry. Controls were 247 neurologically healthy subjects, resident in the study area, age- and gender-matched to cases. The frequency of ≥31 polyQ ATNX2 repeats was significantly more common in ALS cases (4 patients vs. no control, p = 0.0001). All patients with ≥31 polyQ repeats had a spinal onset versus 73.3% of patients with <31 polyQ repeats. Patients with an increased number of polyQ repeats have a shorter survival than those with <31 repeats (1.2 vs. 4.2 years, p = 0.035). In this large series of ALS patients of Sardinian ancestry, we have found that ≥31 polyQ repeats of the ATXN2 gene influenced patients' phenotype, being associated to a spinal onset and a significantly shorter survival.

HFE p.H63D polymorphism does not influence ALS phenotype and survival

It has been recently reported that the p.His63Asp polymorphism of the HFE gene accelerates disease progression both in the SOD1 transgenic mouse and in amyotrophic lateral sclerosis (ALS) patients. We have evaluated the effect of HFE p.His63Asp polymorphism on the phenotype in 1351 Italian ALS patients (232 of Sardinian ancestry). Patients were genotyped for the HFE p.His63Asp polymorphism (CC, GC, and GG). All patients were also assessed for C9ORF72, TARDBP, SOD1, and FUS mutations. Of the 1351 ALS patients, 363 (29.2%) were heterozygous (GC) for the p.His63Asp polymorphism and 30 (2.2%) were homozygous for the minor allele (GG). Patients with CC, GC, and GG polymorphisms did not significantly differ by age at onset, site of onset of symptoms, and survival; however, in SOD1 patients with CG or GG polymorphism had a significantly longer survival than those with a CC polymorphism. Differently from what observed in the mouse model of ALS, the HFE p.His63Asp polymorphism has no effect on ALS phenotype in this large series of Italian ALS patients.

The role of TREM2 R47H as a risk factor for Alzheimer's disease, frontotemporal lobar degeneration, amyotrophic lateral sclerosis, and Parkinson's disease

A rare variant in TREM2 (p.R47H, rs75932628) was recently reported to increase the risk of Alzheimer's disease (AD) and, subsequently, other neurodegenerative diseases, i.e. frontotemporal lobar degeneration (FTLD), amyotrophic lateral sclerosis (ALS), and Parkinson's disease (PD). Here we comprehensively assessed TREM2 rs75932628 for association with these diseases in a total of 19,940 previously untyped subjects of European descent. These data were combined with those from 28 published data sets by meta-analysis. Furthermore, we tested whether rs75932628 shows association with amyloid beta (Aβ42) and total-tau protein levels in the cerebrospinal fluid (CSF) of 828 individuals with AD or mild cognitive impairment. Our data show that rs75932628 is highly significantly associated with the risk of AD across 24,086 AD cases and 148,993 controls of European descent (odds ratio or OR = 2.71, P = 4.67 × 10(-25)). No consistent evidence for association was found between this marker and the risk of FTLD (OR = 2.24, P = .0113 across 2673 cases/9283 controls), PD (OR = 1.36, P = .0767 across 8311 cases/79,938 controls) and ALS (OR = 1.41, P = .198 across 5544 cases/7072 controls). Furthermore, carriers of the rs75932628 risk allele showed significantly increased levels of CSF-total-tau (P = .0110) but not Aβ42 suggesting that TREM2's role in AD may involve tau dysfunction.

Identification of an 18 bp deletion in the TWIST1 gene by CO-amplification at lower denaturation temperature-PCR (COLD-PCR) for non-invasive prenatal diagnosis of craniosynostosis: first case report

BACKGROUND

Non-invasive prenatal diagnosis has found application in a limited number of genetic diseases due to the difficulty in detecting a few copies of fetal mutated sequences in the presence of a large excess of wild-type maternal alleles, even in the case of single-base mutations.

METHODS

We developed conditions for the enrichment of fetal mutated alleles in maternal plasma based on CO-amplification at lower denaturation temperature-PCR (COLD-PCR). In particular, we applied a full COLD-PCR protocol to the identification of a p.A87_G92del mutation in the TWIST1 gene causing craniosynostosis in a couple at risk for the disease.

RESULTS

The use of the COLD-PCR protocol coupled with direct sequencing enabled correct identification of the fetal paternally inherited mutated allele, in accordance with the result obtained on DNA extracted from chorionic villi.

CONCLUSIONS

COLD-PCR proved to be a simple and powerful tool for the identification of minority mutated alleles even in the case of a moderately large deletion (18 bp) and confirmed to be very suitable for non-invasive prenatal diagnosis of a variety of genetic diseases.

Cognitive correlates in amyotrophic lateral sclerosis: a population-based study in Italy

BACKGROUND

There is less data available regarding the characteristics of cognitive impairment in patients with amyotrophic lateral sclerosis (ALS) in a population-based series.

METHODOLOGY

Patients with ALS incident in Piemonte, Italy, between 2009 and 2011 underwent an extensive neuropsychological battery. Cognitive status was classified as follows: normal cognition, frontotemporal dementia (ALS-FTD), executive cognitive impairment (ALS-ECI), non-executive cognitive impairment (ALS-NECI), behavioural impairment (ALS-Bi), non-classifiable cognitive impairment. We also assessed 127 age-matched and gender-matched controls identified through patients' general practitioners.

RESULTS

Out of the 281 incident patients, 207 (71.9%) underwent the neuropsychological testing; of these, 19 were excluded from the analysis due previous conditions affecting cognition. Ninety-one (49.7%) patients were cognitively normal, 23 (12.6%) had ALS-FTD, 36 (19.7%) ALS-ECI, 10 (5.5%) ALS-NECI, 11 (6.0%) ALS-Bi and 11 (6.0%) non-classifiable cognitive impairment, 1 had comorbid Alzheimer's disease. Patients with ALS-FTD were older, had a lower education level, and had a shorter survival than any other cognitive group. Of the nine cases with C9ORF72 mutation, six had ALS-FTD, two ALS-ECI and one was cognitively normal; one of the five patients with SOD1 mutations and one of the five patients with TARBDP mutations had ALS-Bi.

CONCLUSIONS

About 50% of Italian patients with ALS had some degree of cognitive impairment, in keeping with a previous Irish study, despite the largely different genetic background of the two populations. The lower educational attainment in patients with ALS-FTD indicated a possible role of cognitive reserve in ALS-related cognitive impairment. ALS-ECI and ALS-NECI may represent discrete cognitive syndromes in the continuum of ALS and FTD.

CHCH10 mutations in an Italian cohort of familial and sporadic amyotrophic lateral sclerosis patients

Mutations in CHCHD10 have recently been described as a cause of frontotemporal dementia (FTD) comorbid with amyotrophic lateral sclerosis (ALS). The aim of this study was to assess the frequency and clinical characteristics of CHCHD10 mutations in Italian patients diagnosed with familial (n = 64) and apparently sporadic ALS (n = 224). Three apparently sporadic patients were found to carry c.100C>T (p.Pro34Ser) heterozygous variant in the exon 2 of CHCHD10. This mutation had been previously described in 2 unrelated French patients with FTD-ALS. However, our patients had a typical ALS, without evidence of FTD, cerebellar or extrapyramidal signs, or sensorineural deficits. We confirm that CHCHD10 mutations account for ∼ 1% of Italian ALS patients and are a cause of disease in subjects without dementia or other atypical clinical signs.

ATXN2 polyQ intermediate repeats are a modifier of ALS survival

OBJECTIVE

To analyze the frequency and clinical characteristics of patients with amyotrophic lateral sclerosis (ALS) with intermediate-length (CAG) expansion (encoding 27-33 glutamines, polyQ) in the ATXN2 gene, in a population-based cohort of Italian patients with ALS (discovery cohort), and to replicate the findings in an independent cohort of consecutive patients from an ALS tertiary center (validation cohort).

METHODS

PolyQ repeats were assessed in 672 patients with incident ALS in Piemonte and Valle d'Aosta regions, Italy, in the 2007-2012 period (discovery cohort); controls were 509 neurologically healthy age- and sex-matched subjects resident in the study area. The validation cohort included 661 patients with ALS consecutively seen between 2001 and 2013 in the ALS Clinic Center of the Catholic University in Rome, Italy.

RESULTS

In the discovery cohort, the frequency of ≥31 polyQ ATNX2 repeats was significantly more common in ALS cases (19 patients vs 1 control, p = 0.0001; odds ratio 14.8, 95% confidence interval 1.9-110.8). Patients with an increased number of polyQ repeats had a shorter survival than those with <31 repeats (median survival, polyQ ≥31, 1.8 years, interquartile range [IQR] 1.3-2.2; polyQ <31, 2.7 years, IQR 1.6-5.1; p = 0.001). An increased number of polyQ repeats remained independently significant at multivariable analysis. In the validation cohort, patients with ≥31 polyQ repeats had a shorter survival than those with <31 repeats (median survival, polyQ ≥31, 2.0 years, IQR 1.5-3.4; polyQ <31, 3.2 years, IQR 2.0-6.4; p = 0.007).

CONCLUSIONS

ATXN2 polyQ intermediate-length repeat is a modifier of ALS survival. Disease-modifying therapies targeted to ATXN2 represent a promising therapeutic approach for ALS.

Genome-wide analysis of the heritability of amyotrophic lateral sclerosis

IMPORTANCE

Considerable advances have been made in our understanding of the genetics underlying amyotrophic lateral sclerosis (ALS). Nevertheless, for the majority of patients who receive a diagnosis of ALS, the role played by genetics is unclear. Further elucidation of the genetic architecture of this disease will help clarify the role of genetic variation in ALS populations.

OBJECTIVE

To estimate the relative importance of genetic factors in a complex disease such as ALS by accurately quantifying heritability using genome-wide data derived from genome-wide association studies.

DESIGN, SETTING, AND PARTICIPANTS

We applied the genome-wide complex trait analysis algorithm to 3 genome-wide association study data sets that were generated from ALS case-control cohorts of European ancestry to estimate the heritability of ALS. Cumulatively, these data sets contained genotype data from 1223 cases and 1591 controls that had been previously generated and are publically available on the National Center for Biotechnology Information database of genotypes and phenotypes website (http://www.ncbi.nlm.nih.gov/gap). The cohorts genotyped as part of these genome-wide association study efforts include the InCHIANTI (aging in the Chianti area) Study, the Piemonte and Valle d'Aosta Register for Amyotrophic Lateral Sclerosis, the National Institute of Neurological Disorders and Stroke Repository, and an ALS specialty clinic in Helsinki, Finland.

MAIN OUTCOMES AND MEASURES

A linear mixed model was used to account for all known single-nucleotide polymorphisms simultaneously and to quantify the phenotypic variance present in ostensibly outbred individuals. Variance measures were used to estimate heritability.

RESULTS

With our meta-analysis, which is based on genome-wide genotyping data, we estimated the overall heritability of ALS to be approximately 21.0% (95% CI, 17.1-24.9) (SE = 2.0%), indicating that additional genetic variation influencing risk of ALS loci remains to be identified. Furthermore, we identified 17 regions of the genome that display significantly high heritability estimates. Eleven of these regions represent novel candidate regions for ALS risk.

CONCLUSIONS AND RELEVANCE

We found the heritability of ALS to be significantly higher than previously reported. We also identified multiple, novel genomic regions that we hypothesize may contain causative risk variants that influence susceptibility to ALS.

A novel p.E121G heterozygous missense mutation of SOD1 in an apparently sporadic ALS case with a 14-year course

The frequency of SOD1 mutations differs among populations: in Italy they account for 13.6% of familial ALS and 0.7% of sporadic cases. We describe an apparently sporadic Italian ALS patient, carrying a novel p.E121G heterozygous missense mutation of SOD1, with a 14-year disease course and a prevalent lower motor neuron phenotype, which are not uncommon among SOD1 mutations carriers. To our knowledge, no other mutation of codon 121 of SOD1 has ever been reported. Three in silico models suggest a deleterious effect of the p.E121G mutation. Nevertheless, further studies are necessary to confirm its pathogenic role and to evaluate eventual genotype-phenotype correlations.

NADPH oxidase (NOX2) activity is a modifier of survival in ALS

NADPH-oxidases (NOX) catalyze the formation of reactive oxygen species (ROS), which play a role in the development of neurological diseases, particularly those generated by the phagocytic isoform NOX2. Increased ROS has been observed in the amyotrophic lateral sclerosis (ALS) SOD1 transgenic mouse, and in this preclinical model the inactivation of NOX2 decreases ROS production and extends survival. Our aim was to evaluate NOX2 activity measuring neutrophil oxidative burst in a cohort of 83 ALS patients, and age- and gender-matched healthy controls. Oxidative burst was measured directly in fresh blood using Phagoburst™ assay by flow cytometry. Mean fluorescence intensity (MFI), emitted in response to different stimuli, leads to produce ROS and corresponds to the percentage of oxidizing cells and their enzymatic activity (GeoMean). No difference was found between the MFI values in cases and controls. NOX2 activity was independent from gender and age, and in patients was not related to disease duration, site of onset (bulbar vs. spinal), or ALSFRS-R score. However, patients with a NOX2 activity lower than the median value showed a 1-year increase of survival from onset (p = 0.011). The effect of NOX2 was independent from other known prognostic factors. These findings are in keeping with the observations in the mouse model of ALS, and demonstrate the strong role of NOX2 in modifying progression in ALS patients. A proper modulation of NOX2 activity might hold therapeutic potential for ALS.

Genetic architecture of ALS in Sardinia

Conserved populations, such as Sardinians, displaying elevated rates of familial or sporadic amyotrophic lateral sclerosis (ALS) provide unique information on the genetics of the disease. Our aim was to describe the genetic profile of a consecutive series of ALS patients of Sardinian ancestry. All ALS patients of Sardinian ancestry, identified between 2008 and 2013 through the Italian ALS Genetic Consortium, were eligible to be included in the study. Patients and controls underwent the analysis of TARDBP, C9ORF72, SOD1, and FUS genes. Genetic mutations were identified in 155 out of 375 Sardinian ALS cases (41.3%), more commonly the p.A382T and p.G295S mutations of TARDBP and the GGGGCC hexanucleotide repeat expansion of C9ORF72. One patient had both p.G295S and p.A382T mutations of TARDBP and 8 carried both the heterozygous p.A382T mutation of TARDBP and a repeat expansion of C9ORF72. Patients carrying the p.A382T and the p.G295S mutations of TARDBP and the C9ORF72 repeat expansion shared distinct haplotypes across these loci. Patients with cooccurrence of C9ORF72 and TARDBP p.A382T missense mutation had a significantly lower age at onset and shorter survival. More than 40% of all cases on the island of Sardinia carry a mutation of an ALS-related gene, representing the highest percentage of ALS cases genetically explained outside of Scandinavia. Clinical phenotypes associated with different genetic mutations show some distinctive characteristics, but the heterogeneity between and among families carrying the same mutations implies that ALS manifestation is influenced by other genetic and nongenetic factors.

De novo nonsense mutation of the FUS gene in an apparently familial amyotrophic lateral sclerosis case

Mutations in C9ORF72, SOD1, TARDBP, and FUS genes account for approximately two-third of familial cases and 5% of sporadic amyotrophic lateral sclerosis (ALS) cases. We present the first case of an ALS patient carrying a de novo nonsense mutation in exon 14 of the FUS gene (c.1483c>t; p.R495X) with an apparently familial ALS. This mutation causes a phenotype characterized by a young age at onset, a rapid course (<24 months), and a bulbar onset with early respiratory involvement with a predominant lower motor neuron disease. De novo mutations could account for a sizable number of apparently sporadic ALS patients carrying mutations of ALS-related genes.

Genetic counselling in ALS: facts, uncertainties and clinical suggestions

The clinical approach to patients with amyotrophic lateral sclerosis (ALS) has been largely modified by the identification of novel genes, the detection of gene mutations in apparently sporadic patients, and the discovery of the strict genetic and clinical relation between ALS and frontotemporal dementia (FTD). As a consequence, clinicians are increasingly facing the dilemma on how to handle genetic counselling and testing both for ALS patients and their relatives. On the basis of existing literature on genetics of ALS and of other late-onset life-threatening disorders, we propose clinical suggestions to enable neurologists to provide optimal clinical and genetic counselling to patients and families. Genetic testing should be offered to ALS patients who have a first-degree or second-degree relative with ALS, FTD or both, and should be discussed with, but not offered to, all other ALS patients, with special emphasis on its major uncertainties. Presently, genetic testing should not be proposed to asymptomatic at-risk subjects, unless they request it or are enrolled in research programmes. Genetic counselling in ALS should take into account the uncertainties about the pathogenicity and penetrance of some genetic mutations; the possible presence of mutations of different genes in the same individual; the poor genotypic/phenotypic correlation in most ALS genes; and the phenotypic pleiotropy of some genes. Though psychological, social and ethical implications of genetic testing are still relatively unexplored in ALS, we recommend multidisciplinary counselling that addresses all relevant issues, including disclosure of tests results to family members and the risk for genetic discrimination.

Mutations in the Matrin 3 gene cause familial amyotrophic lateral sclerosis

MATR3 is an RNA- and DNA-binding protein that interacts with TDP-43, a disease protein linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. Using exome sequencing, we identified mutations in MATR3 in ALS kindreds. We also observed MATR3 pathology in ALS-affected spinal cords with and without MATR3 mutations. Our data provide more evidence supporting the role of aberrant RNA processing in motor neuron degeneration.

Analysis of the KIFAP3 gene in amyotrophic lateral sclerosis: a multicenter survival study

Sporadic amyotrophic lateral sclerosis is a multifactorial disease of environmental and genetic origin. In a previous large multicenter genome wide study, common genetic variation in the Kinesin-Associated Protein 3 (KIFAP3) gene (rs1541160) was reported to have a significant effect on survival in amyotrophic lateral sclerosis patients. However, this could not be replicated in 3 smaller independent cohorts. We conducted a large multicenter multivariate survival analysis (n = 2362) on the effect of genetic variation in rs1541160. The previously reported beneficial genotype did not show a significant improvement in survival in this patient group.

Homozygosity analysis in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) may appear to be familial or sporadic, with recognised dominant and recessive inheritance in a proportion of cases. Sporadic ALS may be caused by rare homozygous recessive mutations. We studied patients and controls from the UK and a multinational pooled analysis of GWAS data on homozygosity in ALS to determine any potential recessive variant leading to the disease. Six-hundred and twenty ALS and 5169 controls were studied in the UK cohort. A total of 7646 homozygosity segments with length >2 Mb were identified, and 3568 rare segments remained after filtering 'common' segments. The mean total of the autosomal genome with homozygosity segments was longer in ALS than in controls (unfiltered segments, P=0.05). Two-thousand and seventeen ALS and 6918 controls were studied in the pooled analysis. There were more regions of homozygosity segments per case (P=1 × 10(-5)), a greater proportion of cases harboured homozygosity (P=2 × 10(-5)), a longer average length of segment (P=1 × 10(-5)), a longer total genome coverage (P=1 × 10(-5)), and a higher rate of these segments overlapped with RefSeq gene regions (P=1 × 10(-5)), in ALS patients than controls. Positive associations were found in three regions. The most significant was in the chromosome 21 SOD1 region, and also chromosome 1 2.9-4.8 Mb, and chromosome 5 in the 65 Mb region. There are more than twenty potential genes in these regions. These findings point to further possible rare recessive genetic causes of ALS, which are not identified as common variants in GWAS.

No evidence for shared genetic basis of common variants in multiple sclerosis and amyotrophic lateral sclerosis

Genome-wide association studies have been successful in identifying common variants that influence the susceptibility to complex diseases. From these studies, it has emerged that there is substantial overlap in susceptibility loci between diseases. In line with those findings, we hypothesized that shared genetic pathways may exist between multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). While both diseases may have inflammatory and neurodegenerative features, epidemiological studies have indicated an increased co-occurrence within individuals and families. To this purpose, we combined genome-wide data from 4088 MS patients, 3762 ALS patients and 12 030 healthy control individuals in whom 5 440 446 single-nucleotide polymorphisms (SNPs) were successfully genotyped or imputed. We tested these SNPs for the excess association shared between MS and ALS and also explored whether polygenic models of SNPs below genome-wide significance could explain some of the observed trait variance between diseases. Genome-wide association meta-analysis of SNPs as well as polygenic analyses fails to provide evidence in favor of an overlap in genetic susceptibility between MS and ALS. Hence, our findings do not support a shared genetic background of common risk variants in MS and ALS.

A case report of AA amyloidosis associated with familial periodic fever syndrome diagnosed after kidney transplantation: never say never

Recurrent or "de novo" AA amyloidosis in the renal allograft is rarely described. We describe a case of severe nephrotic syndrome in a recipient of a kidney graft with a previous diagnosis of polycystic nephropathy caused by AA amyloidosis diagnosed only after the renal transplantation. The disease was possibly a tumor necrosis factor receptor-associated periodic syndrome (TRAPS). TRAPS is a rare hereditary inflammatory disease never reported to the best of our knowledge, as a de novo diagnosis in the transplantation setting. Biopsy of the renal graft, indicated for the onset of heavy proteinuria, and genetic investigation provided the clues for diagnosis.

Systemic AA amyloidosis as a unique manifestation of a combined mutation of TNFRSF1A and MEFV genes

We report the case of a 22-year-old Caucasian woman presenting with a new-onset nephrotic syndrome with normal renal function during the 35th week of pregnancy. AA (secondary) amyloidosis was further diagnosed at the renal biopsy. Extensive genetic testing revealed that the patient was heterozygous for both TNFRSF1A p.R92Q and MEFV p.M694I mutations leading to an autoinflammatory syndrome characterized by amyloid deposition as the sole manifestation.

Lab-on-a-chip: emerging analytical platforms for immune-mediated diseases

Miniaturization of analytical procedures has a significant impact on diagnostic testing since it provides several advantages such as: reduced sample and reagent consumption, shorter analysis time and less sample handling. Lab-on-a-chip (LoC), usually silicon, glass, or silicon-glass, or polymer disposable cartridges, which are produced using techniques inherited from the microelectronics industry, could perform and integrate the operations needed to carry out biochemical analysis through the mechanical realization of a dedicated instrument. Analytical devices based on miniaturized platforms like LoC may provide an important contribution to the diagnosis of high prevalence and rare diseases. In this paper we review some of the uses of Lab-on-a-chip in the clinical diagnostics of immune-mediated diseases and we provide an overview of how specific applications of these technologies could improve and simplify several complex diagnostic procedures.

Extensive genetics of ALS: a population-based study in Italy

OBJECTIVE

To assess the frequency and clinical characteristics of patients with mutations of major amyotrophic lateral sclerosis (ALS) genes in a prospectively ascertained, population-based epidemiologic series of cases.

METHODS

The study population includes all ALS cases diagnosed in Piemonte, Italy, from January 2007 to June 2011. Mutations of SOD1, TARDBP, ANG, FUS, OPTN, and C9ORF72 have been assessed.

RESULTS

Out of the 475 patients included in the study, 51 (10.7%) carried a mutation of an ALS-related gene (C9ORF72, 32; SOD1, 10; TARDBP, 7; FUS, 1; OPTN, 1; ANG, none). A positive family history for ALS or frontotemporal dementia (FTD) was found in 46 (9.7%) patients. Thirty-one (67.4%) of the 46 familial cases and 20 (4.7%) of the 429 sporadic cases had a genetic mutation. According to logistic regression modeling, besides a positive family history for ALS or FTD, the chance to carry a genetic mutation was related to the presence of comorbid FTD (odds ratio 3.5; p = 0.001), and age at onset ≤54 years (odds ratio 1.79; p = 0.012).

CONCLUSIONS

We have found that ∼11% of patients with ALS carry a genetic mutation, with C9ORF72 being the commonest genetic alteration. Comorbid FTD or a young age at onset are strong indicators of a possible genetic origin of the disease.

An ALS case with a novel D90N-SOD1 heterozygous missense mutation

Abstract Amyotrophic lateral sclerosis (ALS) is the most common form of motor neuron disease. We describe the case of a patient with a rapidly progressive form of ALS characterized by both upper and lower motor neuron impairment, no early bulbar signs and severe pain in all four extremities. The patient had a heterozygous c.271G > A mutation in SOD1, leading to an amino acids substitution of asparagine to aspartate at position 90 of the protein chain (p.D90N). Our report confirms that ALS patients with D90 codon heterozygous mutations may be associated with rapid progression and a prominent pain syndrome.

UNC13A influences survival in Italian amyotrophic lateral sclerosis patients: a population-based study

The common variant rs12608932, located within an intron of UNC13A gene on chromosome 19p13.3, has been suggested to influence susceptibility to amyotrophic lateral sclerosis (ALS), as well as survival, in patients of north European descent. To examine this possibility further, we evaluated the association of rs12608932 with susceptibility and survival in a population-based cohort of 500 Italian ALS patients and 1457 Italian control samples. Although rs12608932 was not associated with ALS susceptibility in our series (p = 0.124), it was significantly associated with survival under the recessive model (median survival for AA/AC genotypes = 3.5 years [interquartile range, 2.2-6.4]; CC = 2.5 years [interquartile range, 1.6-4.2]; p = 0.017). Furthermore, rs12608932 genotype remained an independent prognostic factor in Cox multivariable analysis adjusting for other factors known to influence survival (p = 0.023). Overall, minor allele carrier status of rs12608932 was strongly associated with an approximate 1-year reduction of survival in ALS patients, making it a significant determinant of phenotype variation. The identification of UNC13A as a modifier of prognosis among sporadic ALS patients potentially provides a new therapeutic target aimed at slowing disease progression.

Replication of association of CHRNA4 rare variants with sporadic amyotrophic lateral sclerosis: the Italian multicentre study

Neuronal nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels widely expressed throughout the mammalian brain, including bulbar and spinal motor neurons. They are involved in neuroprotection and in control of release of many neurotransmitters, including glutamate. Previous data raised the hypothesis that rare variants in the region coding the intracellular loop subunits of nAChRs might represent one of several genetic risk factors for SALS. The aim of present study was to replicate the study in an independent cohort of ALS patients. We analysed 718 sporadic ALS patients from five Italian ALS centres and 1300 ethnically matched controls. We focused primarily on CHRNA4, encoding α4 subunit, since most mutations were previously detected in this gene. We observed a significant association between CHRNA4 mutations and ALS (OR 2.91; 95% CI 1.4080-6.0453; p = 0.0056). Most mutations detected in patients were not present in the dbSNP134 and in 3500 ethnically matched control chromosomes and affected evolutionary conserved amino acid residues. In conclusion, the present data confirm that CHRNA4 variants are overrepresented in SALS strengthening the hypothesis can they act as predisposing genetic factors for SALS.

C9ORF72 hexanucleotide repeat expansions in the Italian sporadic ALS population

It has been recently reported that a large proportion of patients with familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are associated with a hexanucleotide (GGGGCC) repeat expansion in the first intron of C9ORF72. We have assessed 1757 Italian sporadic ALS cases, 133 from Sardinia, 101 from Sicily, and 1523 from mainland Italy. Sixty (3.7%) of 1624 mainland Italians and Sicilians and 9 (6.8%) of the 133 Sardinian sporadic ALS cases carried the pathogenic repeat expansion. None of the 619 regionally matched control samples (1238 chromosomes) carried the expansion. Twenty-five cases (36.2%) had behavioral FTD in addition to ALS. FTD or unspecified dementia was also detected in 19 pedigrees (27.5%) in first-degree relatives of ALS patients. Cases carrying the C9ORF72 hexanucleotide expansion survived 1 year less than cases who did not carry this mutation. In conclusion, we found that C9ORF72 hexanucleotide repeat expansions represents a sizeable proportion of apparent sporadic ALS in the Italian and Sardinian population, representing by far the most common mutation in Italy and the second most common in Sardinia.

ALS/FTD phenotype in two Sardinian families carrying both C9ORF72 and TARDBP mutations

BACKGROUND

In the isolated population of Sardinia, a Mediterranean island, ∼25% of ALS cases carry either a p.A382T mutation of the TARDBP gene or a GGGGCC hexanucleotide repeat expansion in the first intron of the C9ORF72 gene.

OBJECTIVE

To describe the co-presence of two genetic mutations in two Sardinian ALS patients.

METHODS

We identified two index ALS cases carrying both the p.A382T missense mutation of TARDBP gene and the hexanucleotide repeat expansion of C9ORF72 gene.

RESULTS

The index case of Family A had bulbar ALS and frontemporal dementia (FTD) at 43. His father, who carried the hexanucleotide repeat expansion of C9ORF72 gene, had spinal ALS and FTD at 64 and his mother, who carried the TARDBP gene p.A382T missense mutation, had spinal ALS and FTD at 69. The index case of Family B developed spinal ALS without FTD at 35 and had a rapid course to respiratory failure. His parents are healthy at 62 and 63. The two patients share the known founder risk haplotypes across both the C9ORF72 9p21 locus and the TARDBP 1p36.22 locus.

CONCLUSIONS

Our data show that in rare neurodegenerative causing genes can co-exist within the same individuals and are associated with a more severe disease course.

Valosin-containing protein (VCP) mutations in sporadic amyotrophic lateral sclerosis

We recently reported that mutations in the valosin-containing protein (VCP) gene are a cause of 1%-2% of familial amyotrophic lateral sclerosis (ALS) cases, but their role in the pathogenesis of sporadic ALS is unclear. We undertook mutational screening of VCP in 701 sporadic ALS cases. Three pathogenic variants (p.Arg159Cys, p.Asn387Thr, and p.R662C) were found in three U.S. cases, each of whom presented with progressive upper and lower motor neuron signs consistent with definite ALS by El Escorial diagnostic criteria. Our data indicate that VCP mutations may underlie apparently sporadic ALS but account for <1% of this form of disease.