Disrupted function and axonal distribution of mutant tyrosyl-tRNA synthetase in dominant intermediate Charcot-Marie-Tooth neuropathy

Charcot-Marie-Tooth (CMT) neuropathies are common disorders of the peripheral nervous system caused by demyelination or axonal degeneration, or a combination of both features. We previously assigned the locus for autosomal dominant intermediate CMT neuropathy type C (DI-CMTC) to chromosome 1p34-p35. Here we identify two heterozygous missense mutations (G41R and E196K) and one de novo deletion (153-156delVKQV) in tyrosyl-tRNA synthetase (YARS) in three unrelated families affected with DI-CMTC. Biochemical experiments and genetic complementation in yeast show partial loss of aminoacylation activity of the mutant proteins, and mutations in YARS, or in its yeast ortholog TYS1, reduce yeast growth. YARS localizes to axonal termini in differentiating primary motor neuron and neuroblastoma cultures. This specific distribution is significantly reduced in cells expressing mutant YARS proteins. YARS is the second aminoacyl-tRNA synthetase found to be involved in CMT, thereby linking protein-synthesizing complexes with neurodegeneration.

Glial fibrillary acidic protein mutations in infantile, juvenile, and adult forms of Alexander disease

Alexander disease is a progressive, usually fatal neurological disorder defined by the widespread and abundant presence in astrocytes of protein aggregates called Rosenthal fibers. The disease most often occurs in infants younger than 2 years and has been labeled a leukodystrophy because of an accompanying severe myelin deficit in the frontal lobes. Later onset forms have also been recognized based on the presence of abundant Rosenthal fibers. In these cases, clinical signs and pathology can be quite different from the infantile form, raising the question whether they share the same underlying cause. Recently, we and others have found pathogenic, de novo missense mutations in the glial fibrillary acidic protein gene in most infantile patients examined and in a few later onset patients. To obtain further information about the role of glial fibrillary acidic protein mutations in Alexander disease, we analyzed 41 new patients and another 3 previously described clinically, including 18 later onset patients. Our results show that dominant missense glial fibrillary acidic protein mutations account for nearly all forms of this disorder. They also significantly expand the catalog of responsible mutations, verify the value of magnetic resonance imaging diagnosis, indicate an unexpected male predominance for the juvenile form, and provide insights into phenotype-genotype relations.

CEP290 mutations are frequently identified in the oculo-renal form of Joubert syndrome-related disorders

Joubert syndrome-related disorders (JSRDs) are a group of clinically and genetically heterogeneous conditions that share a midbrain-hindbrain malformation, the molar tooth sign (MTS) visible on brain imaging, with variable neurological, ocular, and renal manifestations. Mutations in the CEP290 gene were recently identified in families with the MTS-related neurological features, many of which showed oculo-renal involvement typical of Senior-Loken syndrome (JSRD-SLS phenotype). Here, we performed comprehensive CEP290-mutation analysis on two nonoverlapping cohorts of JSRD-affected patients with a proven MTS. We identified mutations in 19 of 44 patients with JSRD-SLS. The second cohort consisted of 84 patients representing the spectrum of other JSRD subtypes, with mutations identified in only two patients. The data suggest that CEP290 mutations are frequently encountered and are largely specific to the JSRD-SLS subtype. One patient with mutation displayed complete situs inversus, confirming the clinical and genetic overlap between JSRDs and other ciliopathies.

A recurrent de novo mutation in TMEM106B causes hypomyelinating leukodystrophy

Hypomyelinating leukodystrophies are a heterogeneous group of disorders with a clinical presentation that often includes early-onset nystagmus, ataxia and spasticity and a wide range of severity. Using next-generation sequencing techniques and GeneMatcher, we identified four unrelated patients with brain hypomyelination, all with the same recurrent dominant mutation, c.754G>A p.(Asp252Asn), in TMEM106B. The mutation was confirmed as de novo in three of the cases, and the mildly affected father of the fourth affected individual was confirmed as mosaic for this variant. The protein encoded by TMEM106B is poorly characterized but is reported to have a role in regulation of lysosomal trafficking. Polymorphisms in TMEM106B are thought to modify disease onset in frontotemporal dementia, but its relation to myelination is not understood. Clinical presentation in three of the four patients is remarkably benign compared to other hypomyelinating disorders, with congenital nystagmus and mild motor delay. These findings add TMEM106B to the growing list of genes causing hypomyelinating disorders and emphasize the essential role lysosomes play in myelination.

Steroids in intractable childhood epilepsy: Clinical experience and review of the literature

Steroids and adrenocorticotrophic hormone (ACTH) have been used for the treatment of infantile spasms for several years. However, the use of steroids in the treatment of epilepsy beyond infantile spasms has been limited to only a few studies. We report the experience with steroids in 32 children with intractable epilepsy, not including West syndrome. In 47% there was a decrease in seizure frequency, 25% became seizure free, 11% had a seizure reduction of >50% and 11% had a seizure reduction of <50%. Our study confirms the conclusions of few previous reports of effective adjunctive steroid treatment for children with intractable epilepsy. The possible side effects, however, especially during prolonged therapy remain an important concern.

Loss of paraplegin drives spasticity rather than ataxia in a cohort of 241 patients with SPG7

OBJECTIVE

We took advantage of a large multinational recruitment to delineate genotype-phenotype correlations in a large, trans-European multicenter cohort of patients with spastic paraplegia gene 7 (SPG7).

METHODS

We analyzed clinical and genetic data from 241 patients with SPG7, integrating neurologic follow-up data. One case was examined neuropathologically.

RESULTS

Patients with SPG7 had a mean age of 35.5 ± 14.3 years (n = 233) at onset and presented with spasticity (n = 89), ataxia (n = 74), or both (n = 45). At the first visit, patients with a longer disease duration (>20 years, n = 62) showed more cerebellar dysarthria (p < 0.05), deep sensory loss (p < 0.01), muscle wasting (p < 0.01), ophthalmoplegia (p < 0.05), and sphincter dysfunction (p < 0.05) than those with a shorter duration (<10 years, n = 93). Progression, measured by Scale for the Assessment and Rating of Ataxia evaluations, showed a mean annual increase of 1.0 ± 1.4 points in a subgroup of 30 patients. Patients homozygous for loss of function (LOF) variants (n = 65) presented significantly more often with pyramidal signs (p < 0.05), diminished visual acuity due to optic atrophy (p < 0.0001), and deep sensory loss (p < 0.0001) than those with at least 1 missense variant (n = 176). Patients with at least 1 Ala510Val variant (58%) were older (age 37.6 ± 13.7 vs 32.8 ± 14.6 years, p < 0.05) and showed ataxia at onset (p < 0.05). Neuropathologic examination revealed reduction of the pyramidal tract in the medulla oblongata and moderate loss of Purkinje cells and substantia nigra neurons.

CONCLUSIONS

This is the largest SPG7 cohort study to date and shows a spasticity-predominant phenotype of LOF variants and more frequent cerebellar ataxia and later onset in patients carrying at least 1 Ala510Val variant.

Variant ataxia telangiectasia: clinical and molecular findings and evaluation of radiosensitive phenotypes in a patient and relatives

Variant ataxia telangiectasia (A-T) may be an underdiagnosed entity. We correlate data from radiosensitivity and kinase assays with clinical and molecular data from a patient with variant A-T and relatives. The coding region of ATM was sequenced. To evaluate the functional effect of the mutations, we performed kinase assays and developed a novel S-G2 micronucleus test. Our patient presented with mild dystonia, moderately dysarthric speech, increased serum α-fetoprotein but no ataxia nor telangiectasias, no nystagmus or oculomotor dyspraxia. She has a severe IgA deficiency, but does not have recurrent infections. She is compound heterozygote for ATM c.8122G>A (p.Asp2708Asn) and c.8851-1G>T, leading to in frame loss of 63 nucleotides at the cDNA level. A trace amount of ATM protein is translated from both alleles. Residual kinase activity is derived only from the p.Asp2708Asn allele. The conventional G0 micronucleus test, based on irradiation of resting lymphocytes, revealed a radiosensitive phenotype for the patient, but not for the heterozygous relatives. As ATM is involved in homologous recombination and G2/M cell cycle checkpoint, we optimized an S-G2 micronucleus assay, allowing to evaluate micronuclei in lymphocytes irradiated in the S and G2 phases. This test showed increased radiosensitivity for both the patient and the heterozygous carriers. Intriguingly, heterozygous carriers of c.8851-1G>T (mutation associated with absence of kinase activity) showed a stronger radiosensitive phenotype with this assay than heterozygous carriers of p.Asp2708Asn (mutation associated with residual kinase activity). The modified S-G2 micronucleus assay provided phenotypic insight into complement the diagnosis of this atypical A-T patient.

Expanding CEP290 mutational spectrum in ciliopathies

Ciliopathies are an expanding group of rare conditions characterized by multiorgan involvement, that are caused by mutations in genes encoding for proteins of the primary cilium or its apparatus. Among these genes, CEP290 bears an intriguing allelic spectrum, being commonly mutated in Joubert syndrome and related disorders (JSRD), Meckel syndrome (MKS), Senior-Loken syndrome and isolated Leber congenital amaurosis (LCA). Although these conditions are recessively inherited, in a subset of patients only one CEP290 mutation could be detected. To assess whether genomic rearrangements involving the CEP290 gene could represent a possible mutational mechanism in these cases, exon dosage analysis on genomic DNA was performed in two groups of CEP290 heterozygous patients, including five JSRD/MKS cases and four LCA, respectively. In one JSRD patient, we identified a large heterozygous deletion encompassing CEP290 C-terminus that resulted in marked reduction of mRNA expression. No copy number alterations were identified in the remaining probands. The present work expands the CEP290 genotypic spectrum to include multiexon deletions. Although this mechanism does not appear to be frequent, screening for genomic rearrangements should be considered in patients in whom a single CEP290 mutated allele was identified.

Unilateral internuclear ophthalmoplegia and ipsiversive torsional nystagmus

We report four patients with internuclear ophthalmoplegia and torsional nystagmus, ipsiversive to the side of the medial longitudinal fasciculus (MLF) lesion. The MLF lesion could be responsible for an inactivation of the ipsilateral interstitial nucleus of Cajal inducing a contraversive slow phase. The presence of a corrective ipsiversive quick phase implicates an intact rostral interstitial nucleus of the MLF.

Methylation defect in imprinted genes detected in patients with an Albright's hereditary osteodystrophy like phenotype and platelet Gs hypofunction

BACKGROUND

Pseudohypoparathyroidism (PHP) indicates a group of heterogeneous disorders whose common feature is represented by impaired signaling of hormones that activate Gsalpha, encoded by the imprinted GNAS gene. PHP-Ib patients have isolated Parathormone (PTH) resistance and GNAS epigenetic defects while PHP-Ia cases present with hormone resistance and characteristic features jointly termed as Albright's Hereditary Osteodystrophy (AHO) due to maternally inherited GNAS mutations or similar epigenetic defects as found for PHP-Ib. Pseudopseudohypoparathyroidism (PPHP) patients with an AHO phenotype and no hormone resistance and progressive osseous heteroplasia (POH) cases have inactivating paternally inherited GNAS mutations.

METHODOLOGY/PRINCIPAL FINDINGS

We here describe 17 subjects with an AHO-like phenotype that could be compatible with having PPHP but none of them carried Gsalpha mutations. Functional platelet studies however showed an obvious Gs hypofunction in the 13 patients that were available for testing. Methylation for the three differentially methylated GNAS regions was quantified via the Sequenom EpiTYPER. Patients showed significant hypermethylation of the XL amplicon compared to controls (36 ± 3 vs. 29 ± 3%; p<0.001); a pattern that is reversed to XL hypomethylation found in PHPIb. Interestingly, XL hypermethylation was associated with reduced XLalphaS protein levels in the patients' platelets. Methylation for NESP and ExonA/B was significantly different for some but not all patients, though most patients have site-specific CpG methylation abnormalities in these amplicons. Since some AHO features are present in other imprinting disorders, the methylation of IGF2, H19, SNURF and GRB10 was quantified. Surprisingly, significant IGF2 hypermethylation (20 ± 10 vs. 14 ± 7%; p<0.05) and SNURF hypomethylation (23 ± 6 vs. 32 6%; p<0.001) was found in patients vs. controls, while H19 and GRB10 methylation was normal.

CONCLUSION/SIGNIFICANCE

In conclusion, this is the first report of methylation defects including GNAS in patients with an AHO-like phenotype without endocrinological abnormalities. Additional studies are still needed to correlate the methylation defect with the clinical phenotype.

Infantile and juvenile presentations of Alexander's disease: a report of two cases

We describe 2 new cases of Alexander's disease, the first to be reported in Belgium. The first patient, a 4-year-old girl, presented with progressive megalencephaly, mental retardation, spastic tetraparesis, ataxia and epilepsy: post-mortem examination showed widespread myelin loss with Rosenthal fibers (RFs) accumulation throughout the neuraxis. She was the third of heterozygotic twins, the 2 others having developed normally and being alive at age 5 years. The second patient developed at age 10 years and over a decade spastic paraparesis, palatal myoclonus, nystagmus, thoracic hyperkyphosis and thoraco-lumbar scoliosis with radiological findings of bilateral anterior leukoencephalopathy. Brain stereotactic biopsy at age 16 years demonstrated numerous RFs. With these 2 cases, we review the literature on the various clinico-pathological conditions reported as Alexander's disease. We discuss the nosology of this entity and the pathogeny of RFs formation and dysmyelination. Clues to the diagnosis of this encephalopathy in the living patient are briefly described.

A 10-year follow-up of the European multicenter trial of interferon β-1b in secondary-progressive multiple sclerosis

OBJECTIVES

To explore long-term effects of treatment and prognostic relevance of variables assessed at baseline and during the European secondary progressive multiple sclerosis (SPMS) trial of interferon beta 1b (IFNB-1b).

METHODS

We assessed 362 patients (60% female; median age 41 years; Expanded Disability Status Scale (EDSS): 5.5; 51% randomized to IFNB-1b) for their EDSS and treatment history after 10 years. Non-parametric analysis of covariance (ANCOVA) and multivariate linear regression models were applied.

RESULTS

Median EDSS was 6.0 at the end of the randomized controlled trial (RCT), in the IFNB-1b and placebo groups, and 7.0 in long-term follow-up patients (those receiving IFNB-1b in the RCT were 6.5 and those receiving placebo in the RCT were 7.0; p = 0.086). 24 patients (6.6%) were deceased. The EDSS at baseline and the EDSS change during the RCT were the most important predictors of the EDSS 10 years later (partial R(2): 0.47). The ability to predict changes in EDSS 10 years after the RCT was limited (R(2): 0.12). Magnetic resonance imaging (MRI) measures remained in the predictive models, but explained < 5% of the variability.

CONCLUSIONS

The results from this analysis did not provide convincing evidence to support a favorable long-term outcome in those patients allocated IFNB-1b during the RCT, in our SPMS cohort. The progressive stage of the disease remains largely unpredictable by clinical and conventional MRI measures, so better prognostic markers are needed.

FIFA's approach to doping in football

BACKGROUND AND OBJECTIVES

FIFA's anti-doping strategy relies on education and prevention. A worldwide network of physicians guarantees doping control procedures that are straightforward and leave no place for cheating. FIFA actively acknowledges its responsibility to protect players from harm and ensure equal chances for all competitors by stringent doping control regulations, data collection of positive samples, support of research, and collaboration with other organisations. This article aims to outline FIFA's approach to doping in football.

METHOD

Description of FIFA's doping control regulations and procedures, statistical analysis of FIFA database on doping control, and comparison with data obtained by WADA accredited laboratories as for 2004.

RESULTS

Data on positive doping samples per substance and confederation/nation documented at the FIFA medical office from 1994 to 2005 are provided. According to the FIFA database, the incidence of positive cases over the past 11 years was 0.12%, with about 0.42% in 2004 (based on the assumption of 20,750 samples per year) and 0.37% in 2005. Especially important in this regard is the extremely low incidence of the true performance enhancing drugs such as anabolic steroids and stimulants. However, there is a need for more consistent data collection and cross checks among international anti-doping agencies as well as for further studies on specific substances, methods, and procedures. With regard to general health impairments in players, FIFA suggests that principles of occupational medicine should be considered and treatment with banned substances for purely medical reasons should be permitted to enable players to carry out their profession. At the same time, a firm stand has to be taken against suppression of symptoms by medication with the aim of meeting the ever increasing demands on football players.

CONCLUSION

Incidence of doping in football seems to be low, but much closer collaboration and further investigation is needed with regard to banned substances, detection methods, and data collection worldwide.

Classical Friedreich's ataxia and its genotype

Fourteen patients with classical features of Friedreich's ataxia (FRDA) were examined. The clinical diagnosis of FRDA was afterwards confirmed in all patients by the appropriate DNA investigation which showed markedly increased amounts of GAA repeats on both alleles of the frataxin gene. None of our patients presented with atypical features such as late-onset FRDA, FRDA with retained deep tendon reflexes or with a very slow course. Five of them are not yet confined to a wheelchair. But for 1 patient who died at age 36 years and had the largest number of GAA repeats on both alleles, there was no significant correlation between number of repeats in the shortest allele, age at onset, age at wheelchair dependence, duration of the disease and main clinical signs. All patients but 3 had between 500 and 1,050 GAA repeats. The 3 patients with, respectively, 400, 450 and 500 repeats on the shortest allele had a clinical course comparable to the other patients. Even in the case of variations in the number of repeats in the same sibship, there were only modest differences between the siblings concerning age at onset of the disease, symptoms and signs and age at wheelchair dependence. There were no qualitative differences in the main clinical features and laboratory investigations in the full-blown phase of the disorder. Molecular biology has become a major element in the diagnosis of FRDA. DNA testing for FRDA should be applied to every case of idiopathic autosomal recessive or sporadic ataxia. However, the clinical features of FRDA remain fully characteristic in many patients and keep their diagnostic value.

Autosomal dominant in cis D4Z4 repeat array duplication alleles in facioscapulohumeral dystrophy

Facioscapulohumeral dystrophy (FSHD) has a unique genetic aetiology resulting in partial chromatin relaxation of the D4Z4 macrosatellite repeat array on 4qter. This D4Z4 chromatin relaxation facilitates inappropriate expression of the transcription factor DUX4 in skeletal muscle. DUX4 is encoded by a retrogene that is embedded within the distal region of the D4Z4 repeat array. In the European population, the D4Z4 repeat array is usually organized in a single array that ranges between 8 and 100 units. D4Z4 chromatin relaxation and DUX4 derepression in FSHD is most often caused by repeat array contraction to 1-10 units (FSHD1) or by a digenic mechanism requiring pathogenic variants in a D4Z4 chromatin repressor like SMCHD1, combined with a repeat array between 8 and 20 units (FSHD2). With a prevalence of 1.5% in the European population, in cis duplications of the D4Z4 repeat array, where two adjacent D4Z4 arrays are interrupted by a spacer sequence, are relatively common but their relationship to FSHD is not well understood. In cis duplication alleles were shown to be pathogenic in FSHD2 patients; however, there is inconsistent evidence for the necessity of an SMCHD1 mutation for disease development. To explore the pathogenic nature of these alleles we compared in cis duplication alleles in FSHD patients with or without pathogenic SMCHD1 variant. For both groups we showed duplication-allele-specific DUX4 expression. We studied these alleles in detail using pulsed-field gel electrophoresis-based Southern blotting and molecular combing, emphasizing the challenges in the characterization of these rearrangements. Nanopore sequencing was instrumental to study the composition and methylation of the duplicated D4Z4 repeat arrays and to identify the breakpoints and the spacer sequence between the arrays. By comparing the composition of the D4Z4 repeat array of in cis duplication alleles in both groups, we found that specific combinations of proximal and distal repeat array sizes determine their pathogenicity. Supported by our algorithm to predict pathogenicity, diagnostic laboratories should now be furnished to accurately interpret these in cis D4Z4 repeat array duplications, alleles that can easily be missed in routine settings.

Harlequin syndrome in a pediatric population: a case series

Harlequin syndrome is a rare condition, presenting with unilateral facial flushing and hyperhidrosis in response to physical exercise, heat or emotional stressors and has scarcely been reported in pediatric patients. It is caused by a dysfunction of vasomotor and sudomotor sympathetic fiber activity inhibiting the ability to flush on the affected side, causing the neurologically intact side to appear red. We present three pediatric cases of this uncommon syndrome, each of them of different origin and displaying distinct associated (neurological) symptoms, and review medical literature. Insight into the anatomical structure of the thoracocervical and facial sympathetic nervous system is pivotal as it dictates symptomatology. About half of Harlequin syndrome cases are complicated with ocular symptoms and a minority may be part of more extensive partial dysautonomias affecting facial sudomotor, vasomotor and pupillary responses, such as Holmes-Adie syndrome and Ross syndrome. Etiology is generally idiopathic, however, cases secondary to surgery, trauma or infection have been described. Considering its predominantly self-limiting nature, treatment is usually unnecessary and should be restricted to incapacitating cases.

Double-blind, parallel-group evaluation of etodolac and naproxen in patients with acute sports injuries

The efficacy and safety of etodolac and naproxen were compared in a double-blind, randomized, parallel-group outpatient study. Patients with acute sports injuries were assigned to receive either etodolac 300 mg TID (50 patients) or naproxen 500 mg BID (49 patients) for up to 7 days. Assessments were made at the pretreatment screening (baseline) and at days 2, 3, 4, and 7 of treatment. Assessments included patient and physician global evaluations, spontaneous and induced pain intensity, range of motion, tenderness, heat, degree of swelling, and degree of erythema. Safety assessments, including laboratory profiles, were made at pretreatment and at final evaluation; patients' complaints were elicited at all visits. Both treatment groups showed significant (P less than or equal to 0.05) improvement from baseline for all efficacy parameters by day 2 and thereafter at all time points. Improvement was similar for the two groups. No patients in either group withdrew from the study because of drug-related adverse reactions. The results of this study indicate that etodolac (900 mg/day) is effective and well tolerated as an analgesic and anti-inflammatory in acute sports injuries and is comparable to naproxen (1000 mg/day).

Nutritional intake evolution in adolescent sporting boys over the last two decades

The AIM of the study was to evaluate the nutritional trends in young elite male soccer players, attending national soccer league at RFC Bruges over the last two decades. At the start of each season, players and parents are instructed about normal healthy nutrition and fluid intake by dieticians.

METHODS

Since 1983, dieticians perform dietary habit surveys in the adolescent player groups. They instruct players and parents how to record all food and fluid intake during 3 days, a training-day, a match-day and an off -day. It is asked to do the recordings when players and parents are together and parents are asked to supervise the recording. Intakes are calculated using the Becel institute nutrition software (BINS), Becel, 2003.

RESULTS

A significant decrease of energy intake/m2 is observed over the last 20 years. Body composition, measured as age-matched body mass index remained at median levels for the population during this period. An important modification of dietary content towards the recommended daily intakes is observed. Fat, saturated fat and cholesterol intake decreased dramatically. Carbohydrate intake increased.

CONCLUSIONS

A positive evolution towards the recommended dietary composition is observed over the years. However, the decrease in caloric intake without influence on the body mass index could suggest that these elite male footballers have a decreased physical activity as compared to 20 years ago.