Anti-Argonaute antibodies as a potential biomarker in NMOSD.

BACKGROUND AND OBJECTIVES: Neuromyelitis optica spectrum disorders (NMOSDs) are a group of diseases mainly characterised by recurrent optic neuritis and/or myelitis. Most cases are associated with a pathogenic antibody against aquaporin-4 (AQP4-Ab), while some patients display autoantibodies targeting the myelin oligodendrocyte glycoprotein (myelin oligodendrocyte glycoprotein antibodies (MOG-Abs)). Anti-Argonaute antibodies (Ago-Abs) were first described in patients with rheumatological conditions and were recently reported as a potential biomarker in patients with neurological disorders. The aims of the study were to investigate if Ago-Abs can be detected in NMOSD and to evaluate its clinical usefulness. METHODS: Sera from patients prospectively referred to our centre with suspected NMOSD were tested for AQP4-Abs, MOG-Abs and Ago-Abs with cell-based assays. RESULTS: The cohort included 104 prospective patients: 43 AQP4-Abs-positive cases, 34 MOG-Abs positive cases and 27 double-negative patients. Ago-Abs were detected in 7 of 104 patients (6.7%). Clinical data were available for six of seven patients. The median age at onset of patients with Ago-Abs was 37.5 [IQR 28.8-50.8]; five of six patients tested positive also for AQP4-Abs. Clinical presentation at onset was transverse myelitis in five patients, while one presented with diencephalic syndrome and experienced a transverse myelitis during follow-up. One case presented a concomitant polyradiculopathy. Median EDSS score at onset was 7.5 [IQR 4.8-8.4]; median follow-up was 40.3 months [IQR 8.3-64.7], and median EDSS score at last evaluation was 4.25 [IQR 1.9-5.5]. CONCLUSION: Ago-Abs are present in a subset of patients with NMOSD and, in some cases, represent the only biomarker of an autoimmune process. Their presence is associated with a myelitis phenotype and a severe disease course.

Early-onset epileptic encephalopathy related to germline PIGA mutations: A series of 5 cases.

The molecular diagnosis of early-onset epileptic encephalopathy (EOEE), an expanding field in child neurology, is becoming increasingly possible thanks to the widespread availability of next-generation sequencing and whole-exome sequencing. In the past 15 years, mutations in STXBP1, KCNQ2, SCN2A, SCN8A and numerous other genes have been reported, giving a more accurate insight for these rare diseases. Among these genes, germline mutations in Phosphatidyl Inositol Glycan A (PIGA) gene were first reported in 2012. Located on Xp22.2, PIGA is involved in the synthesis of GPI (glycosylphosphatidylinositol) which acts as a membrane anchor for different proteins: enzymes, adhesion molecules, regulation of the complement way, and co-receptor in transduction signal. Children suffering from this condition exhibit developmental delay with early-onset epilepsy, severe dysmorphic signs, multi-visceral anomalies and early death in the most severe forms. Here, we report five cases of germline PIGA mutations, with two missense mutations that have not been reported to date. We provide a new insight into the electroclinical phenotype. At the onset, epileptic spasms and focal-onset seizures with upper limbs and ocular involvements were present. Epilepsy proved pharmacoresistant in 4 out of 5 cases. Interictal EEG may be normal at the onset of epilepsy, but abnormalities in electroencephalographic studies were eventually present in all cases. Different types of seizures may be present simultaneously, and epileptic phenotypes evolve with aging.

Expanding the Spectrum of Neurological Manifestations in Cutis Laxa, Autosomal Recessive, Type IIIA.

Cutis laxa is a heterogeneous group of diseases, characterized by abundant and wrinkled skin and a variable degree of intellectual disability. Cutis laxa, autosomal recessive, type IIIA and autosomal dominant 3 syndromes are caused by autosomal recessive or de novo pathogenic variants in ALDH18A1. Autosomal recessive variants are known to lead to the most severe neurological phenotype, and very few patients have been described.We describe a 13-month-old patient with cutis laxa, autosomal recessive, type IIIA, with an extremely severe phenotype, including novel neurological findings. This description enlarges the neurological spectrum associated to cutis laxa, autosomal recessive, type IIIA, and provides an additional description of this syndrome.

Clinical dose effect and functional consequences of R92Q in two families presenting with a TRAPS/PFAPA-like phenotype.

BACKGROUND: TNF receptor-associated syndrome (TRAPS) is a dominantly inherited autoinflammatory condition caused by mutations in the TNFRSF1A gene. The mechanism underlying the variable expressivity of the common variant R92Q (rs4149584; c.362G>A; p.Arg121Gln) is unclear and is of critical importance for patient care and genetic counseling. This study evaluated the impact of the number of R92Q mutations in two unique unrelated families. METHODS: Two patients with undefined but clear autoinflammatory symptoms were referred for genetic diagnosis. Blood samples were collected from the available family members to screen autoinflammatory genes and assess key steps of the TNFR1-mediated signaling pathway using flow cytometry and ex vivo culture. RESULTS: R92Q homozygosity was demonstrated for the two probands. In family 1, the segregation analysis revealed TRAPS-like symptoms in all carriers, with a more severe presentation in the proband, whereas in family 2, the heterozygous parents were totally asymptomatic, suggesting recessive transmission. Functional studies revealed a nonclassical pathogenesis of TRAPS in the two probands and suggested a compensatory mechanism without clear dose effect. CONCLUSION: We observed for the first time a possible clinical dose effect of R92Q. This work highlights the importance of familial studies to reconcile the contradictory reports published on the pathogenicity of this variant.

Extracranial vertebral artery dissection in children: natural history and management.

INTRODUCTION: The objective of this study is to describe clinical and imaging presentation and outcome in extracranial vertebral artery dissection. METHODS: Single-centre retrospective study over a 14-year period included 20 consecutive patients under the age of 16 years with extracranial vertebral artery dissection. The diagnosis was based on vascular imaging performed at the acute phase and clinical symptoms. RESULTS: A male predominance was observed (sex ratio 9/1). The first symptoms consisted of headache (45%), neck pain (15%), nausea (30%) and vertigo (30%). Clinical signs leading to admission to hospital were hemiparesis (60%), visual disorders with oculomotor disorders (20%) or visual field defects (20%) and cerebellar syndrome (35%). Eight patients (40%) reported repeated transient episodes of neurological deficits, prior to the diagnosis. The segment most commonly affected was V2-V3 (50%), followed by V3 (15%) and V2 (15%), V3-V4 (10%) and proximal V4 (10%). All patients but one presented cerebral infarction. Eleven patients received first-line treatment with low molecular weight heparin (LMWH), and nine patients received aspirin. Three patients experienced a recurrence of symptoms, one under vitamin K antagonist (VKA) and 2 under aspirin. All three were switched to LMWH with success. Fifty-eight percent of the dissected arteries were occluded at long-term follow-up, although 73% of them were patent at the acute phase. CONCLUSION: Initial imaging must include posterior fossa vessels and the craniocervical region with V2-V3 segments. Conventional angiography may be indicated in the absence of a definitive diagnosis on noninvasive imaging. Healing of the dissected vertebral artery predominantly resulted in occlusion, which does not constitute a pejorative factor but indicates good quality healing.

Childhood CIDP: Study of 31 patients and comparison between slow and rapid-onset groups.

OBJECTIVES: To describe 31 children presenting a CIDP; to compare patients with rapid-onset disease vs. patients with slow-onset disease, a rapid-onset disease being defined by a time to peak impairment of less than 8 weeks. STUDY DESIGN: A retrospective chart review identified 31 patients completing criteria for childhood CIDP, with 24 "confirmed CIDP" and 7 "possible CIDP". Data collected were time to peak impairment, clinical presentation, cerebrospinal fluid analysis, nerve conduction study, nerve biopsy, treatments. Evaluation at the end of follow-up was reported according to modified Rankin scale. RESULTS: Thirteen patients (42%) exhibited symptoms in less than 2 months with more often cranial nerve abnormalities (38% vs. 6%, p = 0.059), and sensitive symptoms (62% vs. 11%, p = 0.0057). They evolved predominantly in a relapsing way (69% vs. 22%, p = 0.0047). Length of the disease was also longer in the rapid-onset group (5.5 years vs. 3.83 years) but without statistical difference. The slow-onset group exhibited more frequently ataxia at onset (28% vs. 8%, p > 0.05), and evolved predominantly in a progressive manner (61% vs. 15%, p > 0.05). Outcome was similar and good in the two groups. At least 3 out of the 4 major electrophysiological criteria were positive for 27/31 children (87%). Axonal involvement could be present very early. Immunoglobulins were given in 29 cases and corticosteroids in 22. A partial or complete recovery 1 month after first treatment was reported in 30 cases. Among second-line treatments, only azathioprine seemed effective in two out of three intractable children. CONCLUSIONS: The differences noted between the two groups should be tested in wider populations. Electrophysiological criteria are restrictive and axonal involvement should be studied. Prospective trials are required to find out the best first and second line treatments.