A Patient With Charcot-Marie-Tooth Disease Type 4C (CMT4C) Presenting With Muscle Fasciculations and Motor Neuropathy.

We report an unusual patient who, at age 47 years, had presented with complaints of muscle fasciculations. After neurological examination and electromyogram testing, he was diagnosed with motor neuropathy. Over the next 10 years, in addition to fasciculations, he developed numbness in his feet without any other symptoms. His current neurological examination at age 57 years was normal, except for mildly decreased light touch in the anterior portion of both feet. The nerve conduction studies performed repeatedly showed sensorimotor polyneuropathy with demyelination features. Blood tests, including anti-ganglioside antibodies, were normal. Genetic testing revealed two rare variants in trans in the SH3 domain and tetratricopeptide repeats 2gene, c.3413 G>A p.(S1138N) and c.3269 C>G p.(A1090G). Protein modeling suggests that these are disease-producing mutations and likely the cause of the neuropathy of our patient. Our study expands the clinical and genetic spectrum of patients with Charcot-Marie-Tooth disease type 4C.

Demyelinating Peripheral Neuropathy Caused by the p.R160H Mutation in the LITAF Gene.

We report a 62-year-old woman who presented with complaints of numbness and tingling in her feet without a family history suggestive of neuropathy. Neurological examination and electromyogram testing confirmed the presence of a demyelinating neuropathy with a mild phenotype. Extensive testing revealed no etiology and she was diagnosed and treated unsuccessfully for chronic inflammatory demyelinating polyneuropathy. Ultimately, with the availability of next-generation sequencing, genetic testing revealed a heterozygous variant, chr16:11643500C > T, c.479 G > A, p.R160H, in the lipopolysaccharide-induced tumor necrosis factor (LITAF ) gene. Further analysis of this variant employing protein modeling suggests that this is a disease producing mutation causing Charcot Marie Tooth disease type 1C (CMT1C). Our study demonstrates the power of next-generation sequencing to diagnose patients with idiopathic neuropathy. This is important as it avoids unnecessary and expensive treatments for the patient and furthermore, allows genetic counseling for family members.

Novel Titin Gene Mutation Causing Autosomal Dominant Limb-Girdle Muscular Dystrophy.

We report a genotype-phenotype analysis of a family in which a titinopathy is transmitted in an autosomal dominant pattern. In this family, following neurological history and examination, electromyogram, and muscle biopsy, the diagnosis of limb-girdle muscular dystrophy with contractures was made in an affected mother and son. Genetic testing employing the whole exome was performed and revealed two variants in the TTN gene, c.712G>C, p. Glu238Gln and c.1397A>C, p.Gln466Arg, which segregated with the disease in the affected mother-son duo but not in an unaffected sibling. Although protein modeling suggests that the c.712G>C, p. Glu238Gln polymorphism is damaging, it has been reported in the Genome Aggregation Database which includes exome and genome sequence data of unrelated individuals sequenced as part of various disease-specific and population genetic studies. In contrast, the c.1397A>C, p.Gln466Arg variant is novel and has not been reported in any public genetic databases or our internal laboratory database. Protein modeling analysis indicates that p.Gln466Arg is damaging and we hypothesize that it is the disease-producing mutation resulting in muscular dystrophy. Our research report expands the spectrum of mutations causing titinopathy.

Contribution of Common Genetic Variants to Risk of Early Onset Ischemic Stroke.

BACKGROUND AND OBJECTIVES: Current genome-wide association studies of ischemic stroke have focused primarily on late onset disease. As a complement to these studies, we sought to identifythe contribution of common genetic variants to risk of early onset ischemic stroke. METHODS: We performed a meta-analysis of genome-wide association studies of early onset stroke (EOS), ages 18-59, using individual level data or summary statistics in 16,730 cases and 599,237 non-stroke controls obtained across 48 different studies. We further compared effect sizes at associated loci between EOS and late onset stroke (LOS) and compared polygenic risk scores for venous thromboembolism between EOS and LOS. RESULTS: We observed genome-wide significant associations of EOS with two variants in ABO, a known stroke locus. These variants tag blood subgroups O1 and A1, and the effect sizes of both variants were significantly larger in EOS compared to LOS. The odds ratio (OR) for rs529565, tagging O1, 0.88 (95% CI: 0.85-0.91) in EOS vs 0.96 (95% CI: 0.92-1.00) in LOS, and the OR for rs635634, tagging A1, was 1.16 (1.11-1.21) for EOS vs 1.05 (0.99-1.11) in LOS; p-values for interaction = 0.001 and 0.005, respectively. Using polygenic risk scores, we observed that greater genetic risk for venous thromboembolism, another prothrombotic condition, was more strongly associated with EOS compared to LOS (p=0.008). DISCUSSION: The ABO locus, genetically predicted blood group A, and higher genetic propensity for venous thrombosis are more strongly associated with EOS than with LOS, supporting a stronger role of prothrombotic factors in EOS.

Clinical and Genetic Analysis of a Patient with CMT4J.

We report the clinical and genetic analysis of a patient with a rare form of an autosomal recessive genetic neuropathy, Charcot Marie Tooth (CMT) disease type 4J. She presented at age 62 years with signs and symptoms consistent with a mild neuropathy. The onset of symptoms began approximately ten years earlier. Electrophysiological testing confirmed a demyelinating neuropathy and a comprehensive neuropathy screening for common causes of neuropathy was unrevealing. She underwent commercial whole exome sequencing, analyzing more than eighty genes known to cause neuropathy. Two mutations were detected, c.122T > C, p.Ile41Thr and c.2247dupC, p.Ser750GlnX10 in the FIG4 gene. The p.Ile41Thr mutation, which is paternally inherited, is a recurrent mutation reported in a number of unrelated families of European descent. The patient's father, also of European descent, provides further evidence supporting a founder effect for this mutation. In most patients carrying the p.Ile41Thr mutation, the neuropathy, unlike our patient, is often severe with early onset. The second mutation, c.2247dupC, p.Ser750GlnX10 is maternally inherited and not previously reported. Furthermore, based upon our protein modeling analysis, c.2247dupC is disease producing, representing a novel pathogenic mutation. Our study of this patient expands the clinical and genetic spectrum of patients with CMT 4J.

Genotype phenotype analysis in a family carrying truncating mutations in the titin gene.

We report a family carrying a previously described truncating mutation, NM_001267550.2(TTN):c.107889del p.(Lys35963Asnfs*9) in exon 364, and a novel truncating mutation, NM_001267550.1:c.100704C > A p.(Tyr33568*) in exon 358 in the titin gene. The c.107889del mutation, which was maternally transmitted, has been previously described in patients from the Iberian Peninsula. The mother was of Peruvian descent suggesting a potential European ancestral origin of this mutation. In this family, a daughter, who is a compound heterozygote carrying both these mutations, developed a peripartum cardiomyopathy during her second pregnancy. Subsequently, she was diagnosed with a myopathy following electromyography testing and a muscle biopsy which showed fiber type disproportion. Her brother, who carries only the paternally inherited c.100704C > A mutation, developed a cardiomyopathy following a suspected viral illness. Their father, who transmitted this mutation, has no evidence of a cardiomyopathy. We hypothesize that the c.100704C > A mutation confers susceptibility to the development of cardiomyopathy which may be brought on by cardiovascular stress. Our study of this family expands the genotype and phenotype spectrum of disorders that can be associated with mutations in the titin gene.

Genetic basis of lacunar stroke: a pooled analysis of individual patient data and genome-wide association studies.

BACKGROUND: The genetic basis of lacunar stroke is poorly understood, with a single locus on 16q24 identified to date. We sought to identify novel associations and provide mechanistic insights into the disease. METHODS: We did a pooled analysis of data from newly recruited patients with an MRI-confirmed diagnosis of lacunar stroke and existing genome-wide association studies (GWAS). Patients were recruited from hospitals in the UK as part of the UK DNA Lacunar Stroke studies 1 and 2 and from collaborators within the International Stroke Genetics Consortium. Cases and controls were stratified by ancestry and two meta-analyses were done: a European ancestry analysis, and a transethnic analysis that included all ancestry groups. We also did a multi-trait analysis of GWAS, in a joint analysis with a study of cerebral white matter hyperintensities (an aetiologically related radiological trait), to find additional genetic associations. We did a transcriptome-wide association study (TWAS) to detect genes for which expression is associated with lacunar stroke; identified significantly enriched pathways using multi-marker analysis of genomic annotation; and evaluated cardiovascular risk factors causally associated with the disease using mendelian randomisation. FINDINGS: Our meta-analysis comprised studies from Europe, the USA, and Australia, including 7338 cases and 254 798 controls, of which 2987 cases (matched with 29 540 controls) were confirmed using MRI. Five loci (ICA1L-WDR12-CARF-NBEAL1, ULK4, SPI1-SLC39A13-PSMC3-RAPSN, ZCCHC14, ZBTB14-EPB41L3) were found to be associated with lacunar stroke in the European or transethnic meta-analyses. A further seven loci (SLC25A44-PMF1-BGLAP, LOX-ZNF474-LOC100505841, FOXF2-FOXQ1, VTA1-GPR126, SH3PXD2A, HTRA1-ARMS2, COL4A2) were found to be associated in the multi-trait analysis with cerebral white matter hyperintensities (n=42 310). Two of the identified loci contain genes (COL4A2 and HTRA1) that are involved in monogenic lacunar stroke. The TWAS identified associations between the expression of six genes (SCL25A44, ULK4, CARF, FAM117B, ICA1L, NBEAL1) and lacunar stroke. Pathway analyses implicated disruption of the extracellular matrix, phosphatidylinositol 5 phosphate binding, and roundabout binding (false discovery rate <0·05). Mendelian randomisation analyses identified positive associations of elevated blood pressure, history of smoking, and type 2 diabetes with lacunar stroke. INTERPRETATION: Lacunar stroke has a substantial heritable component, with 12 loci now identified that could represent future treatment targets. These loci provide insights into lacunar stroke pathogenesis, highlighting disruption of the vascular extracellular matrix (COL4A2, LOX, SH3PXD2A, GPR126, HTRA1), pericyte differentiation (FOXF2, GPR126), TGF-ß signalling (HTRA1), and myelination (ULK4, GPR126) in disease risk. FUNDING: British Heart Foundation.

Intrafamilial Phenotypic Variability Associated with the I1739V Mutation in the SCN9A Gene.

The SCN9A gene encodes a voltage gated sodium channel Nav1.7 in which mutations can result in a wide variety of phenotypes ranging from congenital insensitivity to pain to small fiber neuropathy. We report the genotype phenotype analysis in a family carrying a specific mutation, I1739V, in the SCN9A gene. Neurophysiological studies have documented the gain of function impact of this mutation on this sodium channel. Interestingly, there is significant interfamilial phenotypic variability in individuals carrying this mutation. In our family, a father daughter combination had identical genotypes analyzing the SCN9A gene and multiple other genes known to cause neuropathy. Both of them carry the I1739V mutation but exhibit significant phenotypic variability with complaints of decreased sensitivity to discomfort in the father while the daughter has the clinical and laboratory features consistent with a small fiber neuropathy. We hypothesize that there are modifiers of the I1739V mutation that could involve intronic or exonic gene variants which contribute to this intrafamilial phenotypic variability. Our study has implications for genetic counseling, personalized medicine and the development of drugs to treat neuropathic pain.

Genome-Wide Association Study Meta-Analysis of Stroke in 22 000 Individuals of African Descent Identifies Novel Associations With Stroke.

BACKGROUND AND PURPOSE: Stroke is a complex disease with multiple genetic and environmental risk factors. Blacks endure a nearly 2-fold greater risk of stroke and are 2× to 3× more likely to die from stroke than European Americans. METHODS: The COMPASS (Consortium of Minority Population Genome-Wide Association Studies of Stroke) has conducted a genome-wide association meta-analysis of stroke in >22 000 individuals of African ancestry (3734 cases, 18 317 controls) from 13 cohorts. RESULTS: In meta-analyses, we identified one single nucleotide polymorphism (rs55931441) near the HNF1A gene that reached genome-wide significance (P=4.62×10-8) and an additional 29 variants with suggestive evidence of association (P<1×10-6), representing 24 unique loci. For validation, a look-up analysis for a 100 kb region flanking the COMPASS single nucleotide polymorphism was performed in SiGN (Stroke Genetics Network) Europeans, SiGN Hispanics, and METASTROKE (Europeans). Using a stringent Bonferroni correction P value of 2.08×10-3 (0.05/24 unique loci), we were able to validate associations at the HNF1A locus in both SiGN (P=8.18×10-4) and METASTROKE (P=1.72×10-3) European populations. Overall, 16 of 24 loci showed evidence for validation across multiple populations. Previous studies have reported associations between variants in the HNF1A gene and lipids, C-reactive protein, and risk of coronary artery disease and stroke. Suggestive associations with variants in the SFXN4 and TMEM108 genes represent potential novel ischemic stroke loci. CONCLUSIONS: These findings represent the most thorough investigation of genetic determinants of stroke in individuals of African descent, to date.

Subtype Specificity of Genetic Loci Associated With Stroke in 16 664 Cases and 32 792 Controls.

BACKGROUND: Genome-wide association studies have identified multiple loci associated with stroke. However, the specific stroke subtypes affected, and whether loci influence both ischemic and hemorrhagic stroke, remains unknown. For loci associated with stroke, we aimed to infer the combination of stroke subtypes likely to be affected, and in doing so assess the extent to which such loci have homogeneous effects across stroke subtypes. METHODS: We performed Bayesian multinomial regression in 16 664 stroke cases and 32 792 controls of European ancestry to determine the most likely combination of stroke subtypes affected for loci with published genome-wide stroke associations, using model selection. Cases were subtyped under 2 commonly used stroke classification systems, TOAST (Trial of Org 10172 Acute Stroke Treatment) and causative classification of stroke. All individuals had genotypes imputed to the Haplotype Reference Consortium 1.1 Panel. RESULTS: Sixteen loci were considered for analysis. Seven loci influenced both hemorrhagic and ischemic stroke, 3 of which influenced ischemic and hemorrhagic subtypes under both TOAST and causative classification of stroke. Under causative classification of stroke, 4 loci influenced both small vessel stroke and intracerebral hemorrhage. An EDNRA locus demonstrated opposing effects on ischemic and hemorrhagic stroke. No loci were predicted to influence all stroke subtypes in the same direction, and only one locus (12q24) was predicted to influence all ischemic stroke subtypes. CONCLUSIONS: Heterogeneity in the influence of stroke-associated loci on stroke subtypes is pervasive, reflecting differing causal pathways. However, overlap exists between hemorrhagic and ischemic stroke, which may reflect shared pathobiology predisposing to small vessel arteriopathy. Stroke is a complex, heterogeneous disorder requiring tailored analytic strategies to decipher genetic mechanisms.

Genetic Analysis of a Large Family with Migraine, Vertigo, and Motion Sickness.

BACKGROUND: Migraine is a common disorder most typically presenting as headache and often associated with vertigo and motion sickness. It is a genetically complex condition with multiple genes ultimately contributing to the predisposition and development of this episodic neurological disorder. We identified a large American family of 29 individuals of which 17 members suffered from at least one of these disorders, migraine, vertigo, or motion sickness. Many of these individuals suffered from several simultaneously. We hypothesized that vertigo and motion sickness may involve genes that are independent to those directly contributing to migraine susceptibility. METHODS: Genome-wide linkage analysis performed using 400 microsatellite repeat markers spaced at 10 cM throughout the genome. The members of this family were phenotyped for each condition, migraine, vertigo, and motion sickness and analyzed separately. Statistical analysis was performed using two-point and multipoint linkage analysis employing a number of models including autosomal recessive or dominant patterns of inheritance with high and low genetic penetrance. RESULTS: We identified a novel locus for migraine, 9q13-q22 (maximum two-point logarithm of odds [LOD] score-2.51). In addition, there are suggestive LOD scores that localize to different chromosomes for each phenotype; vertigo (chromosome 18, LOD score of 1.82) and motion sickness (chromosome 4, LOD score of 2.09). CONCLUSIONS: Our analysis supports our hypothesis that the migraine-associated vertigo and motion sickness may involve distinct susceptibility genes.

Analyse génétique d'une famille étendue dont les membres souffrent de migraines, de vertiges et du mal des transports. Contexte : La migraine est un trouble courant qui entraîne habituellement des maux de tête et qui est souvent associé à des vertiges et au mal des transports. Il s'agit aussi d'une condition génétique complexe en vertu de laquelle de nombreux gènes contribuent à terme à cette prédisposition et au développement de ce trouble neurologique périodique. À cet égard, nous avons identifié une famille étendue américaine comptant 29 membres. De ce nombre, 17 d'entre eux avaient souffert d'au moins un de ces troubles : des migraines, des vertiges ou le mal des transports. À noter que plusieurs d'entre eux avaient souffert de ces troubles en même temps. Nous avons émis l'hypothèse que les vertiges et le mal des transports pourraient impliquer des gènes qui sont indépendants de ceux contribuant directement à la propension aux migraines. Méthodes : Nous avons effectué une analyse de liaison au moyen de 400 marqueurs microsatellites répétés et espacés à tous les 10 cm au sein de l'ensemble du génome des membres de cette famille. Les membres de cette famille ont été « phénotypés ¼ pour chaque type de trouble (les migraines, les vertiges et le mal des transports) et ont été ensuite analysés de façon séparée. Nous avons effectué une analyse statistique au moyen de l'analyse de liaison multipoint et à deux points, utilisant pour ce faire un certain nombre de modèles, par exemple le modèle autosomique récessif ou des patterns dominants de transmission avec une pénétrance génétique élevée ou faible. Résultats : Nous avons été en mesure d'identifier un nouveau locus dans le cas de la migraine : 9q13-q22 (maximum 2-points ; score au logarithme des probabilités ou LOD : - 2,51). De plus, il est des scores révélateurs au logarithme des probabilités qui permettent de localiser divers chromosomes pour chaque phénotype : vertiges (chromosome 18 ; score au logarithme des probabilités ou LOD : 1,82) et mal des transports (chromosome 4 ; score au logarithme des probabilités ou LOD : 2,09). Conclusions : Notre analyse confirme ainsi notre hypothèse initiale, à savoir que les cas de migraine auxquels sont associés des vertiges et le mal des transports pourraient très bien impliquer différents gènes de susceptibilité.

Publisher Correction: Multiancestry genome-wide association study of 520,000 subjects identifies 32 loci associated with stroke and stroke subtypes.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Adult Diagnosis of Type 1 Fiber Predominance Myopathy Caused by Novel Mutations in the RYR1 Gene.

We describe a 57-year-old patient with mild diffuse weakness that was incidentally detected when he was evaluated for restless leg syndrome. An electromyography confirmed the presence of a myopathy without suggestion of inflammatory myopathy. A muscle biopsy demonstrated type 1 fiber predominance with minimal inflammatory features suggesting a genetic myopathy. Exome sequencing revealed c.10648C > T variant (p.R3550W), and a novel variant, c.10749_10753delGGAGG (E3584Rfs*3), in the ryanodine receptor 1 (RYR1) gene transmitted through his asymptomatic father indicating these mutations are in trans. Prompted by these results, a 47-year-old sister presented for evaluation. Her examination showed mild proximal muscle weakness, and an electromyography confirmed a noninflammatory myopathy. Her genotype was identical to her affected brother confirming that in these siblings, the RYR1 mutations, transmitted in an autosomal recessive pattern, are the cause of their myopathy. The adult age at diagnosis of these affected siblings likely reflects the mild and minimally progressive nature of the myopathy.

Limb Girdle Muscular Dystrophy due to Digenic Inheritance of DES and CAPN3 Mutations.

We report the clinical and genetic analysis of a 63-year-old man with progressive weakness developing over more than 20 years. Prior to his initial visit, he underwent multiple neurological and rheumatological evaluations and was treated for possible inflammatory myopathy. He did not respond to any treatment that was prescribed and was referred to our center for another opinion. He underwent a neurological evaluation, electromyography, magnetic resonance imaging of his legs, and a muscle biopsy. All testing indicated a chronic myopathy without inflammatory features suggesting a genetic myopathy. Whole-exome sequencing testing more than 50 genes known to cause myopathy revealed variants in the COL6A3 (rs144651558), RYR1 (rs143445685), CAPN3 (rs138172448), and DES (rs144901249) genes. We hypothesized that the inheritance pattern could follow a digenic pattern of inheritance. Screening for these polymorphisms in an unaffected sister revealed the presence of all these same variants except for that in the CAPN3 gene. All variants were studied to determine their frequency and if they had been previously reported as mutations. They were also subjected to protein modeling programs, including SIFT, PolyPhen, and MutationTaster. This analysis indicated that the CAPN3 variant c.1663G>A (rs138172448), which results in a p.Val555Ile change, and the DES gene variant c.656C>T (rs144901249), which results in a p.Thr219Ile change, are both predicted to be damaging. These 2 variants were further investigated employing the STRING program that analyzes protein networks and pathways. This analysis provided further support for our hypothesis that these mutations in the CAPN3 and DES genes, through digenic inheritance, are the cause of the myopathy in this patient.

Novel Mutation in Anoctamin 5 Gene Causing Limb-Girdle Muscular Dystrophy 2L.

We report a 49-year-old man who presented with a history of asymmetric weakness. His neurological examination and electromyogram testing suggested the presence of a myopathy. A muscle biopsy confirmed the presence of a myopathy with several lobulated, whorled and ring fibers, and it showed no evidence of inflammation. Genetic testing of more than 50 genes known to cause myopathy was performed and demonstrates the presence of the common founder mutation in ANO5 gene c.191dupA, which he inherited from his unaffected father. In addition, he inherited a novel mutation, c.1063C>T (p.L355F) in exon 11 of ANO5 gene from his unaffected mother. The founder mutation is a known pathogenic variant and, based on our protein modeling analysis, the novel c.1063C>T (p.L355F) variant is likely pathogenic. This indicates that he is a compound heterozygote, providing strong support for the diagnosis of limb-girdle muscular dystrophy 2L.

Multiancestry genome-wide association study of 520,000 subjects identifies 32 loci associated with stroke and stroke subtypes.

Stroke has multiple etiologies, but the underlying genes and pathways are largely unknown. We conducted a multiancestry genome-wide-association meta-analysis in 521,612 individuals (67,162 cases and 454,450 controls) and discovered 22 new stroke risk loci, bringing the total to 32. We further found shared genetic variation with related vascular traits, including blood pressure, cardiac traits, and venous thromboembolism, at individual loci (n = 18), and using genetic risk scores and linkage-disequilibrium-score regression. Several loci exhibited distinct association and pleiotropy patterns for etiological stroke subtypes. Eleven new susceptibility loci indicate mechanisms not previously implicated in stroke pathophysiology, with prioritization of risk variants and genes accomplished through bioinformatics analyses using extensive functional datasets. Stroke risk loci were significantly enriched in drug targets for antithrombotic therapy.

Clinical and Genetic Analysis of an Asian Indian Family with Charcot-Marie-Tooth Disease Type 4C.

Charcot-Marie-Tooth disease type 4C, an autosomal recessive genetic neuropathy, is caused by mutations in the SH3TC2 (SH3 domain and tetratricopeptide repeats 2) gene. Interestingly, although mutations in this gene have been observed in European gypsies, a population that originated in India, there are few publications describing Indian patients. We report our analysis of a 50-year-old woman of Asian Indian descent with onset of progressive distal weakness and sensory loss in childhood. A clinical examination revealed the presence of a neuropathy with pes cavus without spinal abnormalities. Electrophysiological testing confirmed a sensorimotor length-dependent neuropathy with demyelinating features. A genetic analysis revealed she carries 2 novel mutations, c.2488G>T variant (rs879254317) and c.731+5G>A variant (rs879254316), in the SH3TC2 gene. Further genetic testing demonstrated that her son is a carrier of the c.731+5G>A mutation. Our analysis confirms that this patient is a compound heterozygote inheriting these mutations, which are in trans, in an autosomal recessive pattern. Her son developed an episode of sciatic neuropathy with complete resolution. We hypothesize that in his case, haploinsufficiency caused by c.731+5G>A mutation may have predisposed him to the development of this focal neuropathy.

Lance-Adams syndrome associated with cerebellar pathology.

Lance-Adams syndrome (LAS) is an uncommon neurological disorder characterized by the development of chronic post-hypoxic myoclonus. There are relatively few cases described following successful cardiopulmonary resuscitation. We report a patient who developed LAS 3 months after successful resuscitation. Cerebral imaging studies indicate that brain pathology in LAS patients is not uniform, suggesting that the pathophysiology of myoclonus may vary from patient to patient. Our patient adds to this etiological heterogeneity by demonstrating the unusual feature of cerebellar pathology by both cerebral magnetic resonance imaging and single-photon emission computed tomography scans. There is also heterogeneity of these patients in their response to therapy. Unlike some patients described in the literature, our patient has not responded to drug treatment. Studies of these rare patients with LAS are important as they provide insight into the pathophysiology of this condition which, it is hopefully, will facilitate the development of more effective therapy.

Genetic variation at 16q24.2 is associated with small vessel stroke.

OBJECTIVE: Genome-wide association studies (GWAS) have been successful at identifying associations with stroke and stroke subtypes, but have not yet identified any associations solely with small vessel stroke (SVS). SVS comprises one quarter of all ischemic stroke and is a major manifestation of cerebral small vessel disease, the primary cause of vascular cognitive impairment. Studies across neurological traits have shown that younger-onset cases have an increased genetic burden. We leveraged this increased genetic burden by performing an age-at-onset informed GWAS meta-analysis, including a large younger-onset SVS population, to identify novel associations with stroke. METHODS: We used a three-stage age-at-onset informed GWAS to identify novel genetic variants associated with stroke. On identifying a novel locus associated with SVS, we assessed its influence on other small vessel disease phenotypes, as well as on messenger RNA (mRNA) expression of nearby genes, and on DNA methylation of nearby CpG sites in whole blood and in the fetal brain. RESULTS: We identified an association with SVS in 4,203 cases and 50,728 controls on chromosome 16q24.2 (odds ratio [OR; 95% confidence interval {CI}] = 1.16 [1.10-1.22]; p = 3.2 × 10-9 ). The lead single-nucleotide polymorphism (rs12445022) was also associated with cerebral white matter hyperintensities (OR [95% CI] = 1.10 [1.05-1.16]; p = 5.3 × 10-5 ; N = 3,670), but not intracerebral hemorrhage (OR [95% CI] = 0.97 [0.84-1.12]; p = 0.71; 1,545 cases, 1,481 controls). rs12445022 is associated with mRNA expression of ZCCHC14 in arterial tissues (p = 9.4 × 10-7 ) and DNA methylation at probe cg16596957 in whole blood (p = 5.3 × 10-6 ). INTERPRETATION: 16q24.2 is associated with SVS. Associations of the locus with expression of ZCCHC14 and DNA methylation suggest the locus acts through changes to regulatory elements. Ann Neurol 2017;81:383-394.

Role of Therapeutic Plasma Exchange in Treatment of Tumefactive Multiple Sclerosis-Associated Low CD4 and CD8 Levels.

We report a 35-year-old healthy male who developed central nervous system inflammatory demyelinating disease consistent with tumefactive multiple sclerosis. About 2 weeks after onset of symptoms and prior to initiation of therapy, the patient had lymphopenia and low CD4 and CD8 levels. His lymphocyte count was 400 cells/µl (850-3,900 cells/µl), CD4 was 193 cells/µl (490-1,740 cells/µl) and CD8 was 103 cells/µl (180-1,170 cells/µl). He was treated with intravenous methylprednisolone followed by therapeutic plasma exchange, the levels of CD4 and CD8 normalized, and ultimately, he recovered completely.