Barbara Leube

The ubiquitin pathway in Parkinson's disease

Mutations of the α-synuclein gene, have been identified in some familial forms of Parkinsons disease, and α-synuclein protein has been shown to accumulate in the brains of patients with the disease. These findings suggest that Parkinsons disease may be caused by the abnormal aggregation of α-synuclein protein. Here we have identified in a German family with Parkinsons disease a missense mutation in the ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) gene. We show that this mutation, Ile93Met, causes a partial loss of the catalytic activity of this thiol protease, which could lead to aberrations in the proteolytic pathway and aggregation of proteins.

Mutations in CIZ1 cause adult-onset primary cervical dystonia

Primary dystonia is usually of adult onset, can be familial, and frequently involves the cervical musculature. Our goal was to identify the causal mutation in a family with adult onset, primary cervical dystonia.

Utility of MLPA in deletion analysis of GCH1 in dopa-responsive dystonia

We applied multiple ligation-dependent probe amplification (MLPA) to patients from three families with characteristic dopa-responsive dystonia (DRD) but no base change in the gene GCH1. We found a complete deletion of GCH1 in affected members of family 1, and partial deletions in affected individuals of family 2 (exons 4–6) and of family 3 (exons 2–6). The findings were confirmed by quantitative real-time PCR. Our investigations demonstrate the utility of MLPA for routine deletion analysis of GCH1 in DRD patients with no sequence changes in this gene.

Clinical, cytogenetic, and molecular observations in a patient with Pallister-Killian-syndrome with an unusual karyotype.

Pallister‐Killian syndrome is a clinically recognizable syndrome, usually due to a tissue‐limited mosaicism for a supernumary 12p isochromosome (i12p). Here we report an unusual case with tetrasomy/trisomy/disomy 12p mosaic in fibroblasts and trisomy/disomy 12p mosaic in lymphocytes. The tetrasomy 12p was due to an i12p, the trisomy 12p to a single 12p marker. Both marker chromosomes were investigated with conventional cytogenetic techniques and fluorescent in situ hybridization (FISH). Stability under culturing conditions was studied. DNA‐analysis revealed prezygotic maternal origin of the extra 12p material. Clinically, the patient seems to have less retardation than most patients with Pallister‐Killian syndrome.

DYT7 Gene Locus for Cervical Dystonia on Chromosome 18p Is Questionable

A locus implicated in autosomal dominant cervical dystonia was assigned to chromosome 18p in 1 large family more than 15 years ago. This locus was designated DYT7. We reanalyzed the family clinically and genetically.

A phenotype map for 14q32.3 terminal deletions.

Detailed molecular‐cytogenetic studies combined with thorough clinical characterization are needed to establish genotype–phenotype correlations for specific chromosome deletion syndromes. Although many patients with subtelomeric deletions have been reported, the phenotype maps for many of the corresponding syndromes, including the terminal deletion 14q syndrome, are only slowly emerging. Here, we report on five patients with terminal partial monosomy of 14q32.3 and characteristic features of terminal deletion 14q syndrome. Four of the patients carry de novo terminal deletions of 14q, three of which have not yet been reported. One patient carries an unbalanced translocation der(14)t(9;14)(q34.3;q32.3). Minimum deletion sizes as determined by molecular karyotyping and FISH are 5.82, 5.56, 4.17, 3.54, and 3.29 Mb, respectively. Based on our findings and a comprehensive review of the literature, we refine the phenotype map for typical clinical findings of the terminal deletion 14q syndrome (i.e., intellectual disability/developmental delay, muscular hypotonia, postnatal growth retardation, microcephaly, congenital heart defects, genitourinary malformations, ocular coloboma, and several dysmorphic signs). Combining this phenotype map with benign copy‐number variation data available from the Database of Genomic Variants, we propose a small region critical for certain features of the terminal deletion 14q syndrome which contains only seven RefSeq genes.

Mutations in CIZ1 are not a major cause for dystonia in Germany.

Primary dystonias are a clinically and genetically heterogeneous group of movement disorders, characterized by involuntary, sustained muscle contractions, frequently causing twisting and repetitive movements or abnormal postures. Whereas most cases of early-onset generalized dystonia are caused by a 3-bp deletion in TOR1A, the exact genetic contribution for the more prevalent adult-onset and localized subtypes of dystonia is unknown. Apart from THAP1, mutations in CIZ1 have been reported to be responsible for autosomal dominantly inherited cervical dystonia in a large Caucasian pedigree. We aimed to evaluate the role of CIZ1 mutations in a series of 683 patients with sporadic and familial forms of predominantly cervical dystonia from movement disorder clinics in Germany (see Supplemental Data Table S1). The CIZ1 coding sequence (ENSG00000148337/ ENST00000393608) and adjacent intronic bases were analyzed by an amplicon-based Next Generation Sequencing approach (n 5 153 patients) and Sanger sequencing (n 5 530 patients). (For Methods, Primers. and NGS quality parameters, see Supplemental Data Tables S2–S5). In the overall combined cohort, we identified mostly annotated single-nucleotide polymorphisms detected at frequencies reported in the Exom variant server database (EVS). (For a summary of variants, see Table 1).

A novel mutation of the SGCE-gene in a German family with myoclonus-dystonia syndrome

Here we describe the clinical and genetic findings of a 40 year old female patient and her 2-years-younger sister (Fig. 1, probands III:1 and III:2) suffering from myoclonus-dystonia syndrome (MDS) with a novel missense mutation in the gene encoding e-sarcoglycan (SGCE), which inhibits the expression of exon 4 and leads to a truncated and, therefore, inactive protein. MDS is an autosomal-dominant inherited disease characterized by a combination of dystonia and myoclonic jerks that frequently respond to ethanol ingestion [1]. Additional non-motor symptoms like anxiety and panic attacks, obsessive–compulsive symptoms, or addiction may coexist. In many cases, mutations in the SGCE-gene have been proven to cause the disease [2]. The two sisters experienced progressive symptoms of dystonia combined with myoclonic features in both lower extremities since the age of 1 year. While the older patient developed additional myoclonic jerks of the head as well as of both arms, particularly during action, the symptoms of her sister were less severe and limited to the lower extremities and the trunk (online resource 1 and 2). No other member of the family was affected (Fig. 1). The patients never suffered from seizures or psychiatric diseases. Cranial MRI, MEP, SSEP, and EEG were normal. Laboratory testing of spinal fluid, urine, and blood did not provide any hints for immunological or metabolic diseases. After extraction and sequencing of the patients’ and their father’s (Fig. 1, proband II:1) DNA, a novel heterozygote point mutation with a substitution of guanosine against adenosine at the last position of exon 4 (c.463G[A) was detected in both patients and their father (Fig. 2a). Different software algorithms suggested a high chance for an aberrant splicing, and thus, the presence of a translationally relevant mutation. This prediction was confirmed with the electrophoresis of the probands’ RT–PCR products on an agarose gel, which revealed a shortened RT– PCR product for both sisters, but not for the father. Sequencing of the short RT–PCR fragment confirmed that the sequence of exon 3 was followed by the sequence of exon 5 (Fig. 2b). The phenomenon of the missing exon 4 in the cDNA had to be due to aberrant splicing, because the coding strand of the sisters’ DNA contained the nucleotide sequence of all exons. As the DNA sequence of exon 4 consists of 73 nucleotides, this aberrant splicing did not only cause a deletion of relevant nucleotides [3, 4], but also predicted to result in an inactive protein due to a frame shift and a stop after 14 amino acids (p.I131TfsX15). In contrast to the findings in both sisters, the RT–PCR product of the father had a regular sequence. Electronic supplementary material The online version of this article (doi:10.1007/s00415-011-5911-6) contains supplementary material, which is available to authorized users.

Blood RNA biomarkers in prodromal PARK4 and rapid eye movement sleep behavior disorder show role of complexin 1 loss for risk of Parkinson's disease

ABSTRACT Parkinsons disease (PD) is a frequent neurodegenerative process in old age. Accumulation and aggregation of the lipid-binding SNARE complex component α-synuclein (SNCA) underlies this vulnerability and defines stages of disease progression. Determinants of SNCA levels and mechanisms of SNCA neurotoxicity have been intensely investigated. In view of the physiological roles of SNCA in blood to modulate vesicle release, we studied blood samples from a new large pedigree with SNCA gene duplication (PARK4 mutation) to identify effects of SNCA gain of function as potential disease biomarkers. Downregulation of complexin 1 (CPLX1) mRNA was correlated with genotype, but the expression of other Parkinsons disease genes was not. In global RNA-seq profiling of blood from presymptomatic PARK4 indviduals, bioinformatics detected significant upregulations for platelet activation, hemostasis, lipoproteins, endocytosis, lysosome, cytokine, Toll-like receptor signaling and extracellular pathways. In PARK4 platelets, stimulus-triggered degranulation was impaired. Strong SPP1, GZMH and PLTP mRNA upregulations were validated in PARK4. When analysing individuals with rapid eye movement sleep behavior disorder, the most specific known prodromal stage of general PD, only blood CPLX1 levels were altered. Validation experiments confirmed an inverse mutual regulation of SNCA and CPLX1 mRNA levels. In the 3′-UTR of the CPLX1 gene we identified a single nucleotide polymorphism that is significantly associated with PD risk. In summary, our data define CPLX1 as a PD risk factor and provide functional insights into the role and regulation of blood SNCA levels. The new blood biomarkers of PARK4 in this Turkish family might become useful for PD prediction. Summary: Complexin 1 is a prodromal biomarker and risk factor for REM sleep behavior disorder and PARK4-associated Parkinsons disease.

Ulna/height ratio as clinical parameter separating EXT1 from EXT2 families?

Multiple osteochondromas (MO) is an autosomal-dominant inherited disorder. The two genes responsible (EXT1 and EXT2) have been identified. We investigated 12 MO families for phenotype details and the genetic basis by cosegregation and mutation analysis (seven novel pathogenic mutations [five frameshift, one splice site, and one gross deletion] and one novel missense polymorphism). We found EXT1 to be responsible in seven families (19 affected members) and EXT2 in four families (17 affected members). One family remains undetermined. We found a tendency to a more severe phenotype in EXT1 families. As a novel finding, we could identify a single parameter (ulna/height ratio) that separates EXT1 family from EXT2 family in our series.