Javier Ruiz-Martínez

Clinical Correlations With Lewy Body Pathology in LRRK2-Related Parkinson Disease

IMPORTANCE Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common cause of genetic Parkinson disease (PD) known to date. The clinical features of manifesting LRRK2 mutation carriers are generally indistinguishable from those of patients with sporadic PD. However, some PD cases associated with LRRK2 mutations lack Lewy bodies (LBs), a neuropathological hallmark of PD. We investigated whether the presence or absence of LBs correlates with different clinical features in LRRK2-related PD. OBSERVATIONS We describe genetic, clinical, and neuropathological findings of 37 cases of LRRK2-related PD including 33 published and 4 unpublished cases through October 2013. Among the different mutations, the LRRK2 p.G2019S mutation was most frequently associated with LB pathology. Nonmotor features of cognitive impairment/dementia, anxiety, and orthostatic hypotension were correlated with the presence of LBs. In contrast, a primarily motor phenotype was associated with a lack of LBs. CONCLUSIONS AND RELEVANCE To our knowledge, this is the first report of clinicopathological correlations in a series of LRRK2-related PD cases. Findings from this selected group of patients with PD demonstrated that parkinsonian motor features can occur in the absence of LBs. However, LB pathology in LRRK2-related PD may be a marker for a broader parkinsonian symptom complex including cognitive impairment.

Parkinson's disease due to the R1441G mutation in Dardarin: A founder effect in the basques

The recent discovery of mutations in Dardarin (LRRK2) have been related to the appearance of Parkinsons disease in several families. Notably, one single mutation in this gene (R1441G) not only appeared in familial, but also in apparently sporadic Parkinson disease (PD) patients of Basque descent. A clinical population was ascertained, and subjects were classified into Basque and non‐Basque descent according to their known ancestry. The R1441G mutation was assayed using an allele‐specific polymerase chain reaction, and several single nucleotide polymorphisms surrounding this mutation were analyzed by direct sequencing. In addition to 22 members of the original Basque families where R1441G was identified, we observed 17 carriers of the mutation who were apparently related through a common ancestor. From a clinical perspective, the disease observed in mutation carriers is indistinguishable from that in noncarriers. The R1441G mutation causes a form of Parkinsons disease that is equivalent to that observed in idiopathic Parkinsons disease. This mutation appears in 16.4% and 4.0% of familial and sporadic PD in this Basque population, respectively.

Clinical outcome in 19 French and Spanish patients with valosin-containing protein myopathy associated with Paget’s disease of bone and frontotemporal dementia

We report the clinical, histological and genetic findings in 10 families (19 patients) presenting mutations in the valosin-containing protein (VCP). The mean age at onset was 42 years. The clinical pattern was characterized by an early involvement of the proximal upper limbs with scapular winging. Axial and lower limb muscles were often affected, whereas facial, oculobulbar muscles were spared. Ten patients were wheelchair bound after a mean disease course of 9 years and six patients required canes for walking. Two patients required mechanically assisted ventilation and seven patients had reduced vital capacity. There was no cardiac involvement. Pagets disease of bone was observed in eight patients and cognitive impairment in nine patients. Seven patients died as a consequence of weakness and respiratory distress. Muscle biopsy showed rimmed vacuolar myopathy. Genetic analysis revealed missense heterozygous mutations mostly located in exon 5 of the VCP gene, four of which were not previously reported. We observed intrafamilial and interfamilial variability in terms of severity, distribution of weakness and presence or not of Pagets disease or cognitive impairment.

LRRK2 G2019S and R1441G mutations associated with Parkinson’s disease are common in the Basque Country, but relative prevalence is determined by ethnicity

Mutations in LRRK2 gene are the most frequent cause of Parkinson’s disease (PD) described, but their prevalence varies between populations. Patients, 418, with PD and 138 unrelated controls from the Basque Country were screened for LRRK2 G2019S and R1441G mutations. Of the patients, 3.82% were heterozygous carriers of G2019S and 13.15% of R1441G. G2019S frequency was higher in non-Basque population (6.0%), while R1441G was more common in Basque origin population (22.4%). Our conclusion is that both G2019S and R1441G mutations’ frequency varies markedly between Basque and non-Basque origin population reinforcing the importance of ethnicity consideration when establishing mutation prevalence.

Mutations in Progranulin Gene: Clinical, Pathological, and Ribonucleic Acid Expression Findings

BACKGROUND There is an increasing interest in the clinico-pathological correlation of mutations in progranulin (PGRN) and frontotemporal lobar degeneration (FTLD) complex diseases. We aim to study the PGRN expression variability in patients with different clinical features for a better understanding of its roles in FTLD disease. METHODS We sequenced the PGRN gene in 72 patients suffering from FTLD (25 familial and 47 sporadic cases) and in 24 asymptomatic at-risk relatives. We also analyzed PGRN expression in blood by quantitative real-time polymerase chain reaction from 37 patients, 8 asymptomatic mutation carriers, and 10 control subjects as well as in brain tissue from 16 patients and 9 control subjects. RESULTS Four novel mutations were associated with familial and sporadic FTLD and familial dementia associated with amyotrophic lateral sclerosis. We identified a close association between the IVS6-1G>A mutation in PGRN and corticobasal syndrome. Brain tissue was available for carriers of two of the four mutations (IVS6-1 G>A and P357HfsX3). Immunohistochemical analysis revealed ubiquitin- and TDP-43positive and tau/alpha-synuclein negative immunoreactive neuronal intranuclear inclusions. The relative expression of PGRN in the clinical sample was significantly lower in carriers of the IVS6-1 G>A than in control subjects. CONCLUSIONS Progranulopathies are a major cause of the main phenotypes included in the FTLD complex. According to our results, the level of expression of PGRN in blood could be a useful marker both for diagnostics of part of the spectrum of FTLD conditions and for monitoring future treatments that might boost the level of PGRN in this disorder.

Olfactory deficits and cardiac 123I‐MIBG in Parkinson's disease related to the LRRK2 R1441G and G2019S mutations

It has been proposed that olfactory tests and metaiodobenzylguanidine cardiac scintigraphy may help diagnose idiopathic Parkinsons disease in the premotor phase. However, it is not clear what value these tests have in all patients with Parkinsons disease and, particularly, in those who carry mutations in LRRK2. The objective was to analyze olfactory dysfunction and the changes in cardiac I‐metaiodobenzylguanidine uptake in patients with Parkinsons disease carrying the R1441G and G2019S mutations in LRRK2, and in patients with Parkinsons disease with no known mutations. Patients with Parkinsons disease were screened for R1441G and G2019S LRRK2 gene mutations and classified as LRRK2 mutation carriers or noncarriers. A total of 190 patients with Parkinsons disease (44 LRRK2 mutation carriers) were tested for olfactory dysfunction using the Brief Smell Identification Test. Cardiac 123I‐metaiodobenzylguanidine scintigraphy was performed on 90 patients with Parkinsons disease (27 LRRK2 mutation carriers). Thirty‐six percent of patients with LRRK2 mutations have hyposmia, compared to 75% of noncarrier patients with Parkinsons disease (P < .001). Sixty‐six percent of LRRK2 mutation carriers have low early metaiodobenzylguanidine uptake, compared to 86% of noncarriers (P = .048). Similarly, the heart/mediastinum ratio in delayed metaiodobenzylguanidine images appeared to differ between these groups of patients with Parkinsons disease, although these results did not reach statistical significance. The data obtained indicate that olfactory and cardiac impairment is less prevalent when Parkinsons disease is associated with mutations in LRRK2, although the underlying mechanisms for this difference remain unclear. Thus, such screening would be less useful to detect the premotor phase in asymptomatic relatives who carry mutations in LRRK2 than in cases not associated with LRRK2.

Neuropathology of Parkinson's Disease with the R1441G Mutation in LRRK2

We report the neuropathological findings in a patient with Parkinsons disease (PD) associated with Basque R1441G‐LRRK2/dardarin mutation. The patient was a man with disease onset at 68 years of age, with unilateral rest tremor; the Parkinsonism was well controlled with medication for 15 years. He died at the age of 86, after 18 years of evolution. The neuropathological examination disclosed mild neuronal loss in the substantia nigra pars compacta without α‐synuclein, tau, LRRK2, or ubiquitin cytoplasmic inclusions. Lewy bodies and Lewy neurites were absent. This is the first neuropathological study of PD associated with brain with the R1441G mutation in LRRK2.

CD24 V/V is an allele associated with the risk of developing multiple sclerosis in the Spanish population.

The allele C in the CD24 gene has been related to multiple sclerosis (MS). In this work we check this single nucleotide polymorphism (SNP) in a population of 135 patients and 285 controls. Our results confirm the association between the V/V genotype at aa 57 of this gene and MS and highlight the importance of taking into account the origin of the subjects to avoid a population bias.

Identification of a novel THAP1 mutation at R29 amino-acid residue in sporadic patients with early-onset dystonia.

Dystonia is a movement disorder characterized by involuntary, sustained muscular contractions affecting one or more sites of the body and abnormal postures. The clinical spectrum of dystonia is diverse: however, the most common form of the disease is primary torsion dystonia (PTD). PTD usually onsets in infancy or adolescence and affects the trunk, neck, or limbs. Two genes are associated with PTD, DYT1 (OMIM 128100; TOR1A) and DYT6 (OMIM 609520; THAP1). Mutations in THAP1 were, first, identified in families presenting with cranial or cervical dystonia that frequently progressed to involve other body regions, and later, in families presenting with early-onset generalized dystonia with prominent spasmodic dysphonia. Here, 24 patients presenting with either generalized (6) or cervical dystonia (18) were investigated for the presence of THAP1 mutations. The mean age at onset was 48 years (range 9–77 years). All patients provided written informed consent to participate in this study. Sequencing analysis of the coding region of the THAP1 gene revealed the presence of a novel c.86G>A transition resulting in p.Arg29Gln in two sporadic cases suffering from early-onset cervical dystonia and early-onset generalized dystonia, respectively. This novel mutation, located in exon 2 of the THAP1 gene, affects an amino-acid previously identified as mutated in families presenting with multifocal and generalized dystonia. Furthermore, R29 amino acid is conserved between species; suggesting, p.Arg29Gln is likely to be pathogenic. Although both p.Arg29Gln mutation carriers are from the same geographical region, there is no evidence of a common founder. A novel silent, mutation which resulted in c.81T>C transition causing p.Leu27Leu was also identified in a sporadic, late-onset dystonia patient presenting with involuntary movements in the neck at the age of sixty; however, its pathogenic role remains unclear. Both novel THAP1 mutations were absent in a Spanish series of 182 control chromosomes. We concluded that pathogenic mutations were only found in early-onset cases. THAP1 mutations occur throughout the entire gene; however, many seem to cluster in the THAP domain of the protein, including the novel THAP1 mutations described here (Fig. 1). It has been suggested that mutations in the THAP domain may reduce the DNA binding ability of THAP; therefore we speculate that mutations at R29 may also act via this mechanism. Clinical features of both patients carrying p.Arg29Gln mutation are described below. This case is a 55 years old man who, at the age of 9, presented with a right-sided torticollis which persisted for more than a year. A surgical intervention was given around his neck and in the right upper limb. Since then, no improvement was determined however the disease showed slow progression. At 54, he noted having cognitive changes and difficulties in speech and ingestion. There was no family history of movement disorders and his mother died with cognitive decline of late onset. Dystonia was mainly present in the face and proximal left upper limb. Left sided torticollis was found with a tendency of retrocollis and fluctuating involvement of both platysma. The trapezia and ECMs were hypertrophic. MRI brain was normal. The cervical spine showed mild disc protrusion at C5-C6 and C6-C7 without radicular involvements. To control the dystonia, increased dose of Botulinum toxin (Dysport), up to 700 units, was required. This case is a 33 years old man who, at the age of 14, presented with abnormal pain sensation in the left upper limb. He progressed to develop dystonic movements in the hand which usually presented as wrist flexion on the radial side and, occasionally, on the ulnar side. In addition, the left upper limb showed forced abduction. Dystonia has now spread to the left foot. His grandmother was diagnosed as having Parkinson’s disease and his great-aunt with possible blepharospasm. Brain MRI was normal and cervical spine showed minimal disc protrusion at C5-C6 without any compression noted. The arm abduction was controlled with botulinum toxin; however, dystonia remained uncontrolled and no additional medication was given. Serum copper, ceruloplasmin, calcium, phosphate, ferritin, and glucose were normal in both cases. To summarize, THAP1 mutations may be present in sporadic, early-onset, cervical, and generalized dystonia.

Apolipoprotein E ɛ4 allele in familial and sporadic Parkinson's disease

Abstract Parkinsons disease (PD) is the second most common age-related neurodegenerative disease after Alzheimers disease (AD). Common risk factors for both diseases have been explored to study potential etiologic interactions between these two neurodegenerative disorders. The APOEɛ4 allele, previously associated with AD, has also been associated with risk of PD and with the presence of some clinical features in PD patients. However, the role of APOE ɛ4 allele in risk of PD remains unclear. We studied the distribution of APOE alleles in 276 unrelated familial and sporadic PD patients and in 212 controls. Patients and controls were classified by ethnicity. No genetic heterogeneity between Basques and people from other regions of Spain was found. No significant differences in APOE allele distribution between PD patients and controls were found; however, lower ɛ4 allele frequency was observed when the sporadic PD group was analyzed separately. By contrast, an increase in ɛ4 allele frequency was found in familial PD patients with cognitive decline. We conclude that the APOE ɛ4 allele may be associated with the risk of developing PD in isolated cases and that it is linked to the presence of cognitive decline in familial PD in our sample.