Lack of mutations in the epsilon-sarcoglycan gene in patients with different subtypes of primary dystonias.

Primary dystonias represent a clinically and genetically heterogeneous group of movement disorders. Mutations in the epsilon-sarcoglycan (SGCE) gene have been found recently to cause myoclonus-dystonia (MD). Considerable clinical variation of SGCE mutation carriers leads to the hypothesis that mutations in the SGCE gene might also be relevant for other subtypes of dystonias. To determine the contribution of mutations in the SGCE gene in patients with different subtypes of dystonias, we analyzed the coding sequence of the SGCE gene in a group of 296 patients with a clinical phenotype of primary dystonia and in 2 patients with a clinical phenotype of myoclonus-dystonia. Patients with mutations in the DYT1 gene were excluded. We could not detect a mutation in the SGCE gene in any of the 298 patients. Our results suggest that mutations in the SGCE gene cannot be held responsible for other subtypes of primary dystonia.     

Genetic heterogeneity in ten families with myoclonus-dystonia

BACKGROUND: Myoclonus-dystonia (M-D) is a movement disorder with autosomal dominant inheritance and reduced penetrance but may also occur sporadically. Recently, mutations in the epsilon-sarcoglycan gene (SGCE) were shown to cause M-D. Furthermore, single variants in the dopamine D2 receptor (DRD2) and DYT1 genes were found in combination with SGCE mutations in two M-D families, and another M-D locus was recently mapped to chromosome 18p11 in one family. METHODS: The authors clinically and genetically characterised ten consecutive cases with myoclonus-dystonia; seven familial and three sporadic. Twenty nine M-D patients and 40 unaffected family members underwent a standardised clinical examination by a movement disorder specialist. Index cases were screened for mutations in the SGCE, DYT1, and DRD2 genes and for deletions of the SGCE gene. Suitable mutation negative families were tested for linkage to the SGCE region and to chromosome 18p11. RESULTS: Two SGCE mutations were detected among the seven familial but no mutation in the sporadic cases. Haplotype analysis at the new M-D locus was compatible with linkage in two families and excluded in another family, suggesting at least one additional M-D gene. There were no obvious clinical differences between M-D families with and without detected mutations. CONCLUSION: M-D is genetically heterogeneous with SGCE mutations accounting for the disease in only part of the clinically typical cases.     

Examination of the SGCE gene in Tourette syndrome patients with obsessive-compulsive disorder.

Mutations in the epsilon-sarcoglycan gene (SGCE) have been reported in families with myoclonus-dystonia (M-D). In addition to abnormal movements, obsessive-compulsive disorder (OCD) has also been described in families with M-D. OCD is a common feature in another movement disorder, namely Tourette syndrome (TS). The comorbidity of these disorders suggests that common genetic factors might be involved in their susceptibility. To evaluate this, we performed two sets of experiments. An association study using a polymorphism within an intron of the SGCE gene was assessed in patients with TS and OCD versus controls, and the SGCE gene itself was screened for mutations in all TS/OCD patients, followed by direct sequencing of the gene in a limited number of these patients. No correlation was found by either method.     

Inherited myoclonus‐dystonia and epilepsy: Further evidence of an association?

Epilepsy and electroencephalogram (EEG) abnormalities have been considered exclusion criteria for the clinical diagnosis of myoclonus-dystonia (M-D). We report on the second M-D family in which several clinically affected epsilon-sarcoglycan gene (SGCE) mutation carriers have seizures in addition to myoclonus and dystonia, adding to the evidence that epilepsy and EEG abnormalities may form part of the phenotypic spectrum of the condition. A nonsense mutation in exon 3 (289C-->T) of SGCE resulting in the insertion of a premature stop codon (R97X) was detected in affected members of this family.     

Myoclonus-dystonia syndrome: epsilon-sarcoglycan mutations and phenotype

Mutations in the gene for epsilon-sarcoglycan (SGCE) have been found to cause myoclonus-dystonia syndrome. We now report clinical and genetic findings in nine additional European families with myoclonus-dystonia syndrome. The clinical presentation in 24 affecteds was homogeneous with myoclonus predominantly of neck and upper limbs in 23 of them and dystonia, presenting as cervical dystonia and/or writer's cramp, in 13 cases. Six novel and one previously known heterozygous SGCE mutations were identified. SGCE deficiency seems to be the common pathogenetic mechanism in myoclonus-dystonia syndrome.     

Epsilon-sarcoglycan mutations found in combination with other dystonia gene mutations

Myoclonus-dystonia is a movement disorder associated with mutations in the epsilon-sarcoglycan gene (SGCE) in most families and in the DRD2 and DYT1 genes in two single families. In both of the latter families, we also found a mutation of SGCE. The molecular mechanisms through which the detected mutations may contribute to myoclonus-dystonia remain to be determined.     

Myoclonus-dystonia due to genomic deletions in the epsilon-sarcoglycan gene

Direct genomic DNA sequencing fails to detect epsilon-sarcoglycan (SGCE) mutations in up to 30% of familial myoclonus-dystonia (M-D) cases. We identified novel large heterozygous deletions of SGCE exon 5 or exon 6 in two M-D pedigrees. Like nonsense mutations, exon rearrangements result in the generation of premature stop codons downstream of the deleted exon. SGCE exon dosage assays may identify additional families with SGCE mutation and thus reduce "genetic heterogeneity."     

Clinical and genetic features of myoclonus-dystonia in 3 cases: a video presentation.

Many cases of myoclonus-dystonia (M-D) are caused by mutations in the epsilon-sarcoglycan (SGCE) gene. We describe 3 children with a similar clinical picture of autosomal dominant M-D and an SGCE mutation in only one of them, suggesting that M-D is genetically heterogeneous.     

Autosomal dominant myoclonus-dystonia and Tourette syndrome in a family without linkage to the SGCE gene.

The objective of this study was to report clinical details and results of genetic testing for mutations in the epsilon-sarcoglycan (SGCE) gene, the Slit and Trk-like 1 (SLITRK1) gene and for linkage to the DYT15, DYT1, and DRD2 gene loci in a family with autosomal dominant myoclonus-dystonia (M-D) and Gilles de la Tourette syndrome (GTS). Fourteen family members, from three generations, underwent a detailed clinical assessment and donated DNA samples. The SGCE and the SLITRK1 gene were sequenced and investigated by gene dosage analysis in selected family members. Linkage to the SGCE, DYT15, DYT1, DRD2, and SLITRK1 loci was also tested. Results: We included three healthy and 11 affected family members with M-D (n = 3), dystonia alone (n = 2), GTS (n = 1), tics (n = 1) or a combination of these with obsessive compulsive disorder (OCD) (M-D + OCD: n = 2; dystonia+OCD: n = 1; M-D + GTS + OCD: n = 1). There was no linkage to the SGCE, DYT15, DYT1 or DRD2 loci. No changes were found in the SLITRK1 gene. The presence of both M-D and GTS in one family, in which all known M-D loci and a recently discovered GTS locus were excluded, suggests a novel susceptibility gene for both M-D and GTS.     

Clinical findings of a myoclonus-dystonia family with two distinct mutations

Myoclonus-dystonia has recently been associated with mutations in the epsilon-sarcoglycan gene (SCGE) on 7q21. Previously, the authors reported a patient with myoclonus-dystonia and an 18-bp deletion in the DYT1 gene on 9q34. The authors have now re-evaluated the patient harboring this deletion for mutations in the SGCE gene and identified a missense change. In the current study, the authors describe the clinical details of this family carrying mutations in two different dystonia genes. Further analysis of these mutations separately and together in cell culture and in animal models should clarify their functional consequences.     

Deep brain stimulation in myoclonus-dystonia syndrome.

Myoclonus-dystonia syndrome (MDS) is an autosomal dominant disorder characterized by bilateral myoclonic jerks. An 8-year-old boy presenting with early onset, medically intractable, MDS due to a mutation in the epsilon-sarcoglycan gene (SGCE) underwent chronic bilateral stimulation of the globus pallidus internus, which eliminates both myoclonus and dystonia. We conclude that deep brain stimulation can be an effective and safe treatment for MDS.     

No muscle involvement in myoclonus-dystonia caused by ɛ-sarcoglycan gene mutations

Mutations in the ɛ-sarcoglycan gene ( SGCE ) can cause autosomal dominant inherited myoclonus-dystonia (M-D). Defects in other sarcoglycans; α-, β-, γ-, and δ can cause autosomal recessive inherited limb girdle muscular dystrophies. ɛ- and α-sarcoglycans are very homologous and may substitute for one-another in different tissues. We therefore investigated whether mutations in SGCE also cause abnormalities of skeletal and myocardial muscle.
Six patients with clinically and genetically verified M-D and no signs of limb-girdle muscular dystrophy were included. Skeletal muscle biopsies were obtained from all patients, and endomyocardial muscle biopsy from one of the patients. Morphological and immunohistological investigations were performed and compared with controls.
Histological and immunohistological investigations of muscle and clinical assessment of muscle strength and mass showed no difference between M-D patients and controls.
Our findings indicate that patients with M-D have no signs or symptoms of muscle disease. This suggests a different role of the sarcoglycan complex ɛβγδ versus αβγδ complex in humans, as earlier suggested in rodents.     

Mutations in the epsilon-sarcoglycan gene found to be uncommon in seven myoclonus-dystonia families

Myoclonus-dystonia syndrome (MDS) is a disorder for which the major cause appears to be mutations in the epsilon-sarcoglycan gene (SGCE). The authors have now performed mutation screening in 22 affected individuals from seven families with findings of typical MDS. A novel 5-bp deletion in exon 7 of the gene in one family and the previously reported R102X nonsense mutation in exon 3 in two other families were identified. Mutations in the SGCE gene were found in the minority of families screened in this series.     

Myoclonus-dystonia, obsessive-compulsive disorder, and alcohol dependence in SGCE mutation carriers

Although myoclonus and dystonia are the hallmarks of myoclonus-dystonia (M-D), psychiatric features, particularly obsessive-compulsive disorder and alcohol dependence, have been reported in three families linked to chromosome 7q21. As the epsilon sarcoglycan (SGCE) gene for M-D was subsequently identified, we evaluated the relationship between psychiatric features and SGCE mutations in these original and two additional families and confirm that OCD and alcohol dependence are associated with manifesting mutated SGCE.     

The epsilon-sarcoglycan gene in myoclonic syndromes

Mutations in the epsilon-sarcoglycan gene (SGCE) are associated with familial myoclonus dystonia, but the full spectrum of the phenotype may not be fully defined. We screened 58 individuals with a range of myoclonic/dystonic syndromes for SGCE mutations. We found mutations (three of them novel) in six (21%) of the 29 patients with essential myoclonus and myoclonic dystonia, but did not find mutations in the 29 patients with other phenotypes.     

Phenotype-genotype correlation in Dutch patients with myoclonus-dystonia

The epsilon-sarcoglycan (SGCE) gene is an important cause of myoclonus-dystonia (M-D), although the majority of cases with an M-D phenotype test negative. Seven of 31 patients with the M-D phenotype carried a mutation in the SGCE gene. Positive family history and truncal myoclonus were independent prognostic factors. Early disease onset, onset with both myoclonus and dystonia, and axial dystonia were detected significantly more often in the mutation carriers.     

A novel conserved mutation in SGCE gene in 3 unrelated patients with classical phenotype myoclonus–dystonia syndrome

Abstract

Objective and importance: Myoclonus–dystonia syndrome (MDS, DYT11) is an inherited disorder characterized by clinical and genetic heterogeneity. MDS is inherited in autosomal dominant pattern and caused by heterozygous mutations in the gene encoding epsilon-sarcoglycan (SGCE) on chromosome 7q21. SGCE gene mutations are present in about 30–50% patients classified as definite-MDS. Earlier onset of motor symptoms is indicated in MDS patients who are SGCE mutations carriers. We present clinical phenotype of three unrelated MDS patients bearing novel, not described yet, mutation in SGCE gene.

Clinical presentation: Presence of a substantial mutation in exon 3, changing aspartic acid to asparagine in codon 96 (D96N) of SGCE protein has been revealed. Three unrelated individuals, bearing the same mutation have diversity of symptoms, with some common features. Age of onset of our patients differs: 2, 14 to 38 years of age.

Intervention/technique: Detection of mutations in SGCE gene was performed via direct sequencing of SGCE gene.

Conclusions: Our results confirm the role of the SGCE gene in the pathogenesis of MDS and call into question the impact of SGCE mutations on the age of onset. The existing list of known mutations and diversity of symptoms in patients bearing the same mutation indicates that there is a lack of genotype–phenotype correlation. Heterogeneity of disease indicates necessity for further research in order to find the molecular fingerprint which may be a landmark in diagnostic studies of MDS.     

Unusual familial presentation of epsilon‐sarcoglycan gene mutation with falls and writer's cramp

Inherited myoclonus dystonia (M‐D, DYT11) is an autosomal dominant dystonia‐plus syndrome, which in many families is caused by mutations in the SGCE/ (epsilon‐sarcoglycan gene. We present a family with M‐D, with an unusual presentation characterized by infantile onset with falls in two sisters and adult‐onset writer's cramp in their father. Myoclonus dystonia is typically characterized by a variable mixture of alcohol‐sensitive myoclonic jerks and dystonia classically affecting mainly the proximal arms and neck. Leg involvement is less frequent, and to our knowledge, initial presentation with falls has not previously been described. The unusual phenotype of the family is discussed. © 2008 Movement Disorder Society.     

Hereditary myoclonus-dystonia associated with epilepsy

A five-generation Dutch family with inherited myoclonus-dystonia (M-D) is described. Genetic analysis revealed a novel truncating mutation within the epsilon-sarcoglycan gene (SGCE). In three of five gene carriers, epilepsy and/or EEG abnormalities were associated with the symptoms of myoclonus and dystonia. The genetic and clinical heterogeneity of M-D is extended. EEG changes and epilepsy should not be considered exclusion criteria for the clinical diagnosis of M-D.