Novel mutations in DNAJB6 cause LGMD1D and distal myopathy in French families.

BACKGROUND AND PURPOSE: The aim was to determine the genetic background of unknown muscular dystrophy in five French families. METHODS: Twelve patients with limb girdle muscular dystrophy or distal myopathy were clinically evaluated. Gene mutations were identified using targeted exon sequencing and mutated DNAJB6 was tested in vitro. RESULTS: Five patients presented with distal lower limb weakness whilst others had proximal presentation with a variable rate of progression starting at the mean age of 38.5 years. Two novel mutations (c.284A>T, p.Asn95Ile, two families; and c.293_295delATG, p.Asp98del, one family) as well as the previously reported c.279C>G (p.Phe93Leu, two families) mutation in DNAJB6 were identified. All showed a reduced capacity to prevent protein aggregation. CONCLUSIONS: The mutational and phenotypical spectrum of DNAJB6-caused muscle disease is larger than previously reported, including also dysphagia. The originally reported c.279C>G (p.Phe93Leu) mutation is now identified in four different populations and appears to be a mutational hotspot. Our report confirms that some DNAJB6 mutations cause distal-onset myopathy and hence DNAJB6 defects should be considered broadly in dominant muscular dystrophy families.

Association study reveals novel risk loci for sporadic inclusion body myositis.

BACKGROUND AND PURPOSE: The aim was to identify potential genetic risk factors associated with sporadic inclusion body myositis (sIBM). METHODS: An association based case-control approach was utilized on whole exome sequencing data of 30 Finnish sIBM patients and a control cohort (n = 193). A separate Italian cohort of sIBM patients (n = 12) was used for evaluation of the results. RESULTS: Seven single nucleotide polymorphisms were identified in five genes that have a considerably higher observed frequency in Finnish sIBM patients compared to the control population, and the previous association of the genetic human leukocyte antigen region was confirmed. CONCLUSIONS: All seven identified variants could individually or in combination increase the susceptibility for sIBM.

Myofibrillar and distal myopathies.

Distal myopathies and myofibrillar myopathies are both rare subcategories of muscle diseases. Myofibrillar myopathies are genetically heterogeneous group of diseases characterized by distinctive histopathology of abnormal protein aggregations and myofibrillar disintegration. All genes causing myofibrillar myopathy encode proteins that either reside in or associate with the Z-disc. Distal myopathies are also genetically heterogeneous muscular dystrophies in which muscle weakness presents distally in the feet and/or hands. A subgroup of distal myopathies, desminopathy, distal myotilinopathy, ZASPopathy and alpha-B crystallin-mutated distal myopathy, belong to myofibrillar myopathies and show similar pathological changes in muscle biopsies. Common features of these diseases are dominant inheritance and adult-onset of symptoms starting in the feet and slowly progressing to encompass other muscle groups. Cardiomyopathy is not a common feature in distal MFM myopathies.

'Pathognomonic' muscle imaging findings in DNAJB6 mutated LGMD1D.

BACKGROUND AND PURPOSE: We have previously reported clinical, genetic and molecular pathomechanistic findings in DNAJB6 mutated LGMD1D. After publishing clinical findings of the original Finnish family we identified more Finnish, Italian and US families with the same disease, ultimately confirmed by mutations in the same gene. METHODS: Of the total number of 28 examined Finnish and Italian patients 23 underwent lower limb muscle imaging. RESULTS: At the early stages of the disease fatty degeneration in T1-weighed MRI sequences were observed in the soleus, adductor magnus, semimembranosus and biceps femoris muscles followed by medial gastrocnemius, adductor longus and later by vasti muscles of the quadriceps. Rectus femoris, lateral gastrocnemius, sartorius, gracilis and the anterolateral group of the lower leg muscles were spared until late senecence. The pattern of differential involvement could be identified at different stages of the disease process. CONCLUSIONS: Since the general clinical findings do not provide clues for diagnosis this distinct pattern of muscle involvement and pathognomonic imaging findings are highly relevant in the clinical setting. The pattern of muscle involvement is so typical that it can be used as a differential diagnostic tool for LGMD1D. The final diagnosis however requires molecular genetic confirmation.

Eight new mutations and the expanding phenotype variability in muscular dystrophy caused by ANO5.

OBJECTIVE: Description of 8 new ANO5 mutations and significant expansion of the clinical phenotype spectrum associated with previously known and unknown mutations to improve diagnostic accuracy. METHODS: DNA samples of 101 patients in 95 kindreds at our quaternary referral center in Finland, who had undetermined limb-girdle muscular dystrophy (LGMD), calf distal myopathy, or creatine kinase (CK) elevations of more than 2,000 IU/L, were selected for ANO5 genetic evaluation, and the clinical findings of patients with mutations were retrospectively analyzed. RESULTS: A total of 25 patients with muscular dystrophy caused by 11 different recessive mutations in the ANO5 gene were identified. The vast majority of mutations, 8 of 11, proved to be previously unknown new mutations. The most frequent mutation, c.2272C>T (p.R758C), was present in 20 patients. The phenotypes associated with this and the common European mutation, c.191dupA, varied from nearly asymptomatic high hyperCKemia to severe LGMD with consistently milder phenotypes in female patients. CONCLUSIONS: Mutations in ANO5 are a frequent cause of undetermined muscular dystrophy, with both distal and proximal presentation. Other types include high hyperCKemia, myalgia, or calf hypertrophy over decades without significant weakness, especially in female patients. Mutations are distributed all over the gene, indicating that muscular dystrophy caused by ANO5 can be expected to occur in all populations.

Increased plasma levels of cytokines after seizures in localization-related epilepsy.

OBJECTIVES: Experimental studies suggest increased cerebral production of inflammatory cytokines after prolonged seizures. Whether a single non-prolonged seizure in human patients is associated with activation of cytokine network is still unknown. MATERIALS AND METHODS: We studied the levels of interleukin-1beta (IL-1beta), interleukin-1 receptor antagonist (IL-1ra), interlukin-6 (IL-6) and soluble IL-6 receptors (sIL-6R and Gp130) in plasma after single seizures during video-EEG recordings in patients with chronic localization-related epilepsy. RESULTS: The levels of IL-1ra and IL-6 were increased after seizures, whereas IL-1beta and IL-6 cytokine receptors remained unchanged. CONCLUSIONS: These results show that only single seizures cause activation of cytokine cascade and associated inflammatory signals. In the case of recurrent seizures, these signals may result in structural changes in the nervous tissue, which are generally associated with drug refractory epilepsy.

Regulation of IL-6 system in cerebrospinal fluid and serum compartments by seizures: the effect of seizure type and duration.

Experimental studies suggest that cytokine production may be triggered by seizure activity. Here we determined the levels of interleukin-6 (IL-6) and its soluble receptor components (sIL-6R and sGp130) in CSF and serum from control subjects and patients after different types of seizures. IL-6 levels were increased after seizures, whereas sIL-6R levels were decreased. Interestingly, the levels of IL-6 were strongly increased after recurrent generalized tonic-clonic seizures (GTCS), whereas after single tonic-clonic or prolonged partial seizures IL-6 levels were increased to lesser extent. These results provide further support for a hypothesis of cytokine production induced by seizure activity per se.

Normal CSF neuron-specific enolase and S-100 protein levels in patients with recent non-complicated tonic-clonic seizures.

PURPOSE: Increased concentrations of the nervous-system-specific proteins neuron-specific enolase (NSE) and S-100 protein (S-100) have been measured with lesions in the CNS. Elevated levels of serum NSE (s-NSE) have been found in status epilepticus, but also after single epileptic seizures. Because larger studies addressing cerebrospinal fluid (CSF) levels of NSE or S-100 have not been performed, we measured CSF NSE and S-100 after tonic-clonic seizures to search for evidence of neuronal and glial damage. METHODS: 22 consecutive patients with single, previously undiagnosed and untreated tonic-clonic seizures were studied. Serum and CSF samples were collected within 24 h after seizure. 18 serum and CSF samples were measured from a control group. RESULTS: The mean CSF NSE was 8.9 ng/ml (range 0-28 ng/ml) and s-NSE 8.2 ng/ml (range 5-15 ng/ml) in the patient group. The mean concentrations in the control group were 13.1 ng/ml (range 3-24 ng/ml) and 8.0 ng/ml (range 5-12 ng/ml) respectively. The mean CSF S-100 was 3.17 microg/l (range 1.45-7.02 microg/l) and serum S-100 0.05 microg/l (range 0-0.32 microg/l), and in controls 3.19 microg/l (range 1.52-5.13 microg/l) and 0.08 microg/l (range 0-0.28 microg/l). CONCLUSION: There were no significant differences between the mean concentrations of NSE or S-100 in CSF and serum between the epileptic group and controls. These results do not confirm the previous observation of elevated NSE-levels after tonic-clonic seizures, which argues against neuronal or glial damage after uncomplicated tonic-clonic seizures in unmedicated patients.

Interleukin-6 and interleukin-1 receptor antagonist in cerebrospinal fluid from patients with recent tonic-clonic seizures.

We have previously reported increased concentrations of interleukin (1L)-6 in CSF from patients with tonic-clonic seizures, where increased cytokine production most likely is a consequence of neuronal epileptic activity associated with seizures. The biological effects of IL-6 are mediated by other cytokines, which are studied here in addition to IL-6. The purpose of this study was to analyze levels of soluble cytokines from plasma and CSF from patients with newly developed tonic-clonic seizures. The concentrations of IL-6, IL-1 receptor antagonist (IL-1RA), IL-1beta, tumor necrosis factor (TNFalpha) and nerve growth factor (NGF) were measured from plasma and CSF from 22 patients with newly developed tonic-clonic seizures within 24 h from the seizure and 18 controls. The mean concentrations of IL-6 were significantly increased in CSF (P<0.001) and plasma (P<0.01) after tonic-clonic seizures, there was some indication of increased concentrations of IL-1RA and no significant change in NGF, IL-1beta or TNFalpha. Our study shows that cytokine network is activated in patients after recent tonic-clonic seizures. We provide evidence of intrathecal production of IL-6 associated with electrical seizure activity.

Autoantibodies to glutamic acid decarboxylase in patients with therapy-resistant epilepsy.

BACKGROUND: Autoantibodies to glutamic acid decarboxylase (GAD-A) are present in type 1 diabetes and stiff man syndrome (SMS), and have also been reported in cerebellar ataxia. Epilepsy was present in 4 of 19 patients with SMS and GAD-A, implying that epilepsy sometimes is associated with anti-GAD autoimmunity. METHODS: The authors investigated the prevalence of GAD-A in patients with therapy-resistant localization-related epilepsy (n = 51) and generalized epilepsy (n = 49) by a radiobinding assay. The positive samples were confirmed by immunohistochemistry and immunoblotting of recombinant human GAD65. RESULTS: GAD-A were found in eight patients with localization-related epilepsy, whereas none of the patients with generalized epilepsy, other neurologic disorders (n = 38), or the control subjects (n = 48) had GAD-A. Two patients had high levels of GAD-A, similar to SMS, whereas six patients had significantly lower titers, characteristic of type 1 diabetes. The two patients with high levels of GAD-A had GAD-A both in serum and CSF by immunohistochemistry and immunoblotting. Both of them had longstanding therapy-resistant temporal lobe epilepsy but did not have diabetes. One had a history of autoimmune disease, whereas the other had serologic evidence of multiple autoantibodies without any clinical signs of autoimmune disease. CONCLUSIONS: GAD autoimmunity may be associated with refractory localization-related epilepsy.

Antiphospholipid and antinuclear antibodies in patients with epilepsy or new-onset seizure disorders.

PURPOSE: The increased prevalence of autoantibodies in patients with epilepsy has been traditionally regarded to be a consequence of antiepileptic drugs. The purpose of this study was to measure autoantibodies in well-defined groups of patients with seizures to determine the effects of epilepsy and antiepileptic medications on the presence of autoantibodies. PATIENTS AND METHODS: We studied the frequency of antinuclear antibodies, anti-beta2-glycoprotein I antibodies, and anticardiolipin antibodies in 50 patients with therapy-resistant localization-related epilepsy, 50 patients with generalized epilepsy syndromes, 52 patients with a newly diagnosed seizure disorder but no antiepileptic medication, and 83 healthy controls. RESULTS: Compared with controls, newly diagnosed patients had a significantly greater prevalence of immunoglobulin (Ig) G class anticardiolipin antibodies (21% versus 7%); the prevalence was 14% in patients with localization-related epilepsy and 8% in patients with generalized epilepsy. The prevalence of IgM class anticardiolipin antibodies was significantly greater in all seizure groups (60% in localization-related epilepsy, 42% in generalized epilepsies, and 33% in newly diagnosed patients) compared with controls (7%). Antinuclear antibodies were significantly more common in newly diagnosed patients (21%) and localization-related epilepsy (24%) compared with controls (12%). When patients with generalized epilepsy (8%) were used as the reference group, antinuclear antibodies were also significantly more frequent in localization-related epilepsy (relative risk [RR] = 2.9, 95% confidence interval [CI]: 1.1 to 8.2) and newly diagnosed seizures (RR = 3.4, 95% CI: 1.2 to 9.3). There were no consistent associations between autoantibodies and specific antiepileptic medications. CONCLUSIONS: The prevalence of autoantibodies is greater in patients with epilepsy, including newly diagnosed seizure disorder. The increased prevalence of autoantibodies is more strongly associated with epilepsy than with antiepileptic drugs, perhaps indicating that immune dysregulation may be commonly associated with epilepsy.