Andres Deik

The p.L302P mutation in the lysosomal enzyme gene SMPD1 is a risk factor for Parkinson disease

Objective: To study the possible association of founder mutations in the lysosomal storage disorder genes HEXA, SMPD1, and MCOLN1 (causing Tay-Sachs, Niemann-Pick A, and mucolipidosis type IV diseases, respectively) with Parkinson disease (PD). Methods: Two PD patient cohorts of Ashkenazi Jewish (AJ) ancestry, that included a total of 938 patients, were studied: a cohort of 654 patients from Tel Aviv, and a replication cohort of 284 patients from New York. Eight AJ founder mutations in the HEXA, SMPD1, and MCOLN1 genes were analyzed. The frequencies of these mutations were compared to AJ control groups that included large published groups undergoing prenatal screening and 282 individuals matched for age and sex. Results: Mutation frequencies were similar in the 2 groups of patients with PD. The SMPD1 p.L302P was strongly associated with a highly increased risk for PD (odds ratio 9.4, 95% confidence interval 3.9–22.8, p < 0.0001), as 9/938 patients with PD were carriers of this mutation compared to only 11/10,709 controls. Conclusions: The SMPD1 p.L302P mutation is a novel risk factor for PD. Although it is rare on a population level, the identification of this mutation as a strong risk factor for PD may further elucidate PD pathogenesis and the role of lysosomal pathways in disease development.

Parkinson disease phenotype in Ashkenazi jews with and without LRRK2 G2019S mutations

The phenotype of Parkinsons disease (PD) in patients with and without leucine‐rich repeat kinase 2 (LRRK2) G2019S mutations reportedly is similar; however, large, uniformly evaluated series are lacking. The objective of this study was to characterize the clinical phenotype of Ashkenazi Jewish (AJ) PD carriers of the LRRK2 G2019S mutation. We studied 553 AJ PD patients, including 65 patients who were previously reported, from three sites (two in New York and one in Tel‐Aviv). Glucocerebrosidase (GBA) mutation carriers were excluded. Evaluations included the Montreal Cognitive Assessment (MoCA), the Unified Parkinsons Disease Rating Scale (UPDRS), the Geriatric Depression Scale (GDS) and the Non‐Motor Symptoms (NMS) questionnaire. Regression models were constructed to test the association between clinical and demographic features and LRRK2 status (outcome) in 488 newly recruited participants. LRRK2 G2019S carriers (n = 97) and non‐carriers (n = 391) were similar in age and age at onset of PD. Carriers had longer disease duration (8.6 years vs. 6.1 years; P < 0.001), were more likely to be women (51.5% vs. 37.9%; P = 0.015), and more often reported first symptoms in the lower extremities (40.0% vs. 19.2%; P < 0.001). In logistic models that were adjusted for age, disease duration, sex, education, and site, carriers were more likely to have lower extremity onset (P < 0.001), postural instability and gait difficulty (PIGD) (P = 0.043), and a persistent levodopa response for >5 years (P = 0.042). Performance on the UPDRS, MoCA, GDS, and NMS did not differ by mutation status. PD in AJ LRRK2 G2019S mutation carriers is similar to idiopathic PD but is characterized by more frequent lower extremity involvement at onset and PIGD without the associated cognitive impairment.

Substance abuse and movement disorders: complex interactions and comorbidities.

The relationship between movement disorders and substance abuse, which we previously reviewed, is updated. We examine these relationships bidirectionally with focus on drugs of abuse that are known to cause movement disorders, as well as primary movement disorders that are associated with use and abuse of alcohol and dopaminergic medications. First, we review the movement disorders that may develop from the acute use or withdrawal of frequent drugs of abuse, including alcohol, cocaine, heroin, amphetamine and methcathinone. We then comment on the interaction between alcoholism and alcohol-responsive movement disorders, such as essential tremor and myoclonus-dystonia. Lastly, we discuss the potential for abuse of antiparkinsonian dopaminergic agents in patients with Parkinsons disease (PD).

Heterogeneity in primary dystonia: Lessons from THAP1, GNAL, and TOR1A in Amish-Mennonites

A founder mutation in the Thanatos‐associated (THAP) domain containing, apoptosis associated protein 1 (THAP1) gene causing primary dystonia was originally described in the Amish‐Mennonites. However, there may be both genotypic and phenotypic heterogeneity of dystonia in this population that may also inform studies in other ethnic groups. Genotyping for THAP1 and for guanine nucleotide binding protein (G protein), α‐activating activity polypeptide, olfactory type (GNAL) mutations and genotype‐phenotype comparisons were performed for 76 individuals of Amish‐Mennonites heritage with primary dystonia. Twenty‐seven individuals had mutations in THAP1—most with the founder indel mutation—but two had different THAP1 mutations, 8 had mutations in GNAL, and 1 had a de novo GAG deletion in torsin 1A (TOR1A) (dystonia 1 [DYT1]). In the primary analysis comparing THAP1 carriers versus all non‐THAP1, non‐GNAL, non‐TOR1A individuals, age at onset was lower in THAP1 carriers (mean age ± standard deviation, 15.5 ± 9.2 years [range, 5‐38 years] vs. 39.2 ± 17.7 years [range, 1‐70 years]; P < 0.001), and THAP1 carriers were more likely to have onset of dystonia in an arm (44.4% vs. 15.0%; P = 0.02) and to have arm involvement (88.9% vs. 22.5%; P < 0.01), leg involvement (51.9% vs. 10.0%; P = 0.01), and jaw/tongue involvement (33.3% vs. 7.5%; P = 0.02) involvement at their final examination. Carriers were less likely to have dystonia restricted to a single site (11.11% in carriers vs. 65.9% in noncarriers; P < 0.01) and were less likely to have dystonia onset in cervical regions (25.9% of THAP1 carriers vs. 52.5% of noncarriers; P = 0.04). Primary dystonia in the Amish‐Mennonites is genetically diverse and includes not only the THAP1 indel founder mutation but also different mutations in THAP1 and GNAL as well as the TOR1A GAG deletion. Phenotype, particularly age at onset combined with final distribution, may be highly specific for the genetic etiology.

Neuropsychiatric characteristics of GBA-associated Parkinson disease

Mutations in GBA1 are a well-established risk factor for Parkinson disease (PD). GBA-associated PD (GBA-PD) may have a higher burden of nonmotor symptoms than idiopathic PD (IPD). We sought to characterize the relationship between GBA-PD and neuropsychiatric symptoms. Subjects were screened for common GBA1 mutations. GBA-PD (n=31) and non-carrier (IPD; n=55) scores were compared on the Unified Parkinson Disease Rating Scale (UPDRS), Montreal Cognitive Assessment (MoCA), Beck Depression Inventory (BDI), and the State-Trait Anxiety Index (STAI). In univariate comparisons, GBA-PD had a greater prevalence of depression (33.3%) versus IPD (13.2%) (p<0.05). In regression models controlling for age, sex, disease duration, motor disability, and MoCA score, GBA-PD had an increased odds of depression (OR 3.66, 95% CI 1.13-11.8) (p=0.03). Post-hoc analysis stratified by sex showed that, among men, GBA-PD had a higher burden of trait anxiety and depression than IPD; this finding was sustained in multivariate models. Among women, GBA-PD did not confer greater psychiatric morbidity than IPD. These results suggest that GBA1 mutations confer greater risk of neuropsychiatric morbidity in PD, and that sex may affect this association.

Clinical Spectrum of Stiff Person Syndrome: A Review of Recent Reports

Background “Classic” stiff person syndrome (SPS) features stiffness, anti-glutamic acid decarboxylase (anti-GAD) antibodies, and other findings. Anti-GAD antibodies are also detected in some neurological syndromes (such as ataxia) in which stiffness is inconsistently present. Patients with otherwise “classic” SPS may either lack anti-GAD antibodies or be seropositive for others. Hence, SPS cases appear to fall within a clinical spectrum that includes conditions such as progressive encephalomyelitis with rigidity and myoclonus (PERM), which exhibits brainstem and autonomic features. We have compiled herein SPS-spectrum cases reported since 2010, and have segregated them on the basis of likely disease mechanism (autoimmune, paraneoplastic, or cryptogenic) for analysis. Methods The phrases “stiff person syndrome”, “PERM”, “anti-GAD antibody syndrome”, and “glycine receptor antibody neurological disorders” were searched for in PubMed in January 2015. The results were narrowed to 72 citations after excluding non-English and duplicate reports. Clinical descriptions, laboratory data, management, and outcomes were categorized, tabulated, and analyzed. Results Sixty-nine autoimmune, 19 paraneoplastic, and 13 cryptogenic SPS-spectrum cases were identified. SPS was the predominant diagnosis among the groups. Roughly two-thirds of autoimmune and paraneoplastic cases were female. Anti-GAD antibodies were most frequently identified, followed by anti-amphiphysin among paraneoplastic cases and by anti-glycine receptor antibodies among autoimmune cases. Benzodiazepines were the most commonly used medications. Prognosis seemed best for cryptogenic cases; malignancy worsened that of paraneoplastic cases. Discussion Grouping SPS-spectrum cases by pathophysiology provided insights into work-up, treatment, and prognosis. Ample phenotypic and serologic variations are present within the categories. Ruling out malignancy and autoimmunity is appropriate for suspected SPS-spectrum cases.

Atypical presentation of late-onset Tay-Sachs disease.

Introduction: Late‐onset Tay‐Sachs disease (LOTS) is a lysosomal storage disease caused by deficient Beta‐hexosaminidase A activity. Methods: We describe a 53‐year‐old woman who presented with adult‐onset leg weakness, and whose initial diagnosis was progressive muscular atrophy without identifiable etiology. Development of cerebellar ataxia in mid‐life prompted reassessment. Results: Beta‐hexosaminidase A quantification assay demonstrated absence of the isozyme. Genetic testing identified compound heterozygous mutations in the HEXA gene, confirming the diagnosis of LOTS. Conclusions: The phenotypic spectrum of LOTS includes motor neuronopathy, ataxia, choreoathetosis, neuropathy, and psychiatric symptoms in various combinations. This patient highlights the emergence of different clinical features over many years and emphasizes the need to consider LOTS in the differential diagnosis of progressive muscular atrophy. Muscle Nerve 49: 768–771, 2014

Compound heterozygous PNPLA6 mutations cause Boucher–Neuhäuser syndrome with late-onset ataxia

PNPLA6 mutations, known to be associated with the development of motor neuron phenotypes, have recently been identified in families with Boucher–Neuhäuser syndrome. Boucher–Neuhäuser is a rare autosomal recessive syndrome characterized by the co-occurrence of cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy. Gait ataxia in Boucher–Neuhäuser usually manifests before early adulthood, although onset in the third or fourth decade has also been reported. However, given the recent identification of PNPLA6 mutations as the cause of this condition, the determining factors of age of symptom onset still need to be established. Here, we have identified a sporadic Boucher–Neuhäuser case with late-onset gait ataxia and relatively milder retinal changes due to compound heterozygous PNPLA6 mutations. Compound heterozygosity was confirmed by cloning and sequencing the patient’s genomic DNA from coding exons 26–29. Furthermore, both mutations (one novel and one known) fell in the phospholipase esterase domain, where most pathogenic mutations seem to cluster. Taken together, we herein confirm PNPLA6 mutations as the leading cause of Boucher–Neuhäuser syndrome and suggest inquiring about a history of hypogonadism or visual changes in patients presenting with late-onset gait ataxia. We also advocate for neuroophthalmologic evaluation in suspected cases.

KDR Mutation as a Novel Predictive Biomarker of Exceptional Response to Regorafenib in Metastatic Colorectal Cancer.

This is the case of an 84-year-old woman diagnosed with Stage IVb colon adenocarcinoma (CRC) metastatic to the liver, retroperitoneum, anastomotic site, and distal rectal sigmoid colon. She experienced intolerable side effects to systemic chemotherapy with 5-fluorouracil and bevacizumab, as well as disease progression. Next generation sequencing of her tumor was ordered, and further discussion of her malignancy’s genomic information took place at a multidisciplinary molecular tumor board. The patient had mutations in KRAS (Kirsten rat sarcoma viral oncogene homolog) which made her ineligible for epidermal growth factor receptor (EGFR) inhibitors; however, a KDR p.R961W c.2881C>T mutation was noted as a variant of unknown significance (VUS). KDR (kinase insert domain receptor) is the human gene encoding for vascular endothelial growth factor receptor 2 (VEGFR-2). She was then considered a suitable candidate for regorafenib, which she could only tolerate at a low dose of 40 mg daily, with the intent of prolonging her survival and to optimize her quality of life. We report her excellent tolerance and exceptional response to low dose regorafenib, including symptomatic, tumor marker, and sustained partial metabolic radiological improvement. In the largest Phase III trial of regorafenib in CRC, only five patients (1%) of 760 experienced a partial response (versus one patient, 0.4%, receiving placebo). KDR R961W mutation has been described but no functional data has been reported. This mutation occurs in the tyrosine kinase domain of the VEGFR-2. Regorafenib targets VEGFR-2 (KDR). Hereby we hypothesize KDR mutation as a novel predictive biomarker to exceptional response to regorafenib in metastatic colorectal cancer. To our knowledge, this is the first reported case of the potential correlation between KDR mutation and regorafenib use for the successful management of a patient with advanced CRC, leading to what is considered an exceptional response. Further studies based on this preliminary data are warranted.

Transcranial sonography and functional imaging in glucocerebrosidase mutation Parkinson disease

BACKGROUND Heterozygous glucocerebrosidase (GBA) mutations are the leading genetic risk factor for Parkinson disease, yet imaging correlates, particularly transcranial sonography, have not been extensively described. METHODS To determine whether GBA mutation heterozygotes with Parkinson disease demonstrate hyperechogenicity of the substantia nigra, transcranial sonography was performed in Ashkenazi Jewish Parkinson disease subjects, tested for the eight most common Gaucher disease mutations and the LRRK2 G2019S mutation, and in controls. [(18)F]-fluorodeoxyglucose or [(18)F]-fluorodopa positron emission tomography is also reported from a subset of Parkinson disease subjects with heterozygous GBA mutations. RESULTS Parkinson disease subjects with heterozygous GBA mutations (n = 23) had a greater median maximal area of substantia nigral echogenicity compared to controls (n = 34, aSNmax = 0.30 vs. 0.18, p = 0.007). There was no difference in median maximal area of nigral echogenicity between Parkinson disease groups defined by GBA and LRRK2 genotype: GBA heterozygotes; GBA homozygotes/compound heterozygotes (n = 4, aSNmax = 0.27); subjects without LRRK2 or GBA mutations (n = 32, aSNmax = 0.27); LRRK2 heterozygotes/homozygotes without GBA mutations (n = 27, aSNmax = 0.28); and GBA heterozygotes/LRRK2 heterozygotes (n = 4, aSNmax = 0.32, overall p = 0.63). In secondary analyses among Parkinson disease subjects with GBA mutations, maximal area of nigral echogenicity did not differ based on GBA mutation severity or mutation number. [(18)F]-fluorodeoxyglucose (n = 3) and [(18)F]-fluorodopa (n = 2) positron emission tomography in Parkinson disease subjects with heterozygous GBA mutations was consistent with findings in idiopathic Parkinson disease. CONCLUSIONS Both transcranial sonography and positron emission tomography are abnormal in GBA mutation associated Parkinson disease, similar to other Parkinson disease subjects.