Extending the phenotypes associated with TRIO gene variants in a cohort of 25 patients and review of the literature.

The TRIO gene encodes a rho guanine exchange factor, the function of which is to exchange GDP to GTP, and hence to activate Rho GTPases, and has been described to impact neurodevelopment. Specific genotype-to-phenotype correlations have been established previously describing striking differentiating features seen in variants located in specific domains of the TRIO gene that are associated with opposite effects on RAC1 activity. Currently, 32 cases with a TRIO gene alteration have been published in the medical literature. Here, we report an additional 25, previously unreported individuals who possess heterozygous TRIO variants and we review the literature. In addition, functional studies were performed on the c.4394A > G (N1465S) and c.6244-2A > G TRIO variants to provide evidence for their pathogenicity. Variants reported by the current study include missense variants, truncating nonsense variants, and an intragenic deletion. Clinical features were previously described and included developmental delay, learning difficulties, microcephaly, macrocephaly, seizures, behavioral issues (aggression, stereotypies), skeletal problems including short, tapering fingers and scoliosis, dental problems (overcrowding/delayed eruption), and variable facial features. Here, we report clinical features that have not been described previously, including specific structural brain malformations such as abnormalities of the corpus callosum and ventriculomegaly, additional psychological and dental issues along with a more recognizable facial gestalt linked to the specific domains of the TRIO gene and the effect of the variant upon the function of the encoded protein. This current study further strengthens the genotype-to-phenotype correlation that was previously established and extends the range of phenotypes to include structural brain abnormalities, additional skeletal, dental, and psychiatric issues.

Current understanding of febrile seizures and their long-term outcomes.

In this paper we reframe febrile seizures, which are viewed as a symptom of an underlying brain disorder. The general observation is that a small cohort of children will develop febrile seizures (2-5% in the West), while the greater majority will not. This suggests that the brain that generates a seizure, in an often-mild febrile context, differs in some ways from the brain that does not. While the underlying brain disorder appears to have no significant adverse implication in the majority of children with febrile seizures, serious long-term outcomes (cognitive and neuropsychiatric) have been recently reported, including sudden death. These adverse events likely reflect the underlying intrinsic brain pathology, as yet undefined, of which febrile seizures are purely a manifestation and not the primary cause. A complex interaction between brain-genetics-epigenetics-early environment is likely at play. In view of this emerging data, it is time to review whether febrile seizures are a single entity, with a new and multidimensional approach needed to help with predicting outcome. WHAT THIS PAPER ADDS: A febrile seizure is due to a brain's aberrant response to high temperature. Problems in a small group of children are now being identified later in life. There is no clear correlation between duration or other characteristics of febrile seizures and subsequent mesial temporal sclerosis.

Guillain-Barré syndrome associated with CASPR2 antibodies: two paediatric cases.

The pathogenesis of Guillain-Barré syndrome (GBS) is considered to be, at least in part, mediated by autoantibodies directed against neuronal antigens. Antibodies to contactin-associated protein-like 2 (CASPR2), part of the voltage-gated potassium channel complex (VGKC-complex), are associated with neurological disease predominantly affecting the peripheral nervous system but are not known to be associated with GBS. We report two cases of ganglioside antibody-negative paediatric GBS associated with CASPR2 antibodies. Both patients made a complete clinical recovery. The tissue distribution and function of CASPR2 make it a biologically plausible autoimmune target in GBS and its clinical relevance in GBS should be determined in further studies.

Movement disorders in GLUT1 deficiency syndrome respond to the modified Atkins diet.

BACKGROUND: Movement disorders are a prominent feature of glucose transporter-1 (GLUT1) deficiency syndrome (GLUT1DS). First-choice treatment is a ketogenic diet, but compliance is poor. We have investigated the effect of the modified Atkins diet as an alternative treatment for movement disorders in GLUT1DS. METHODS: Four patients with GLUT1DS ages 15 to 30 years who had movement disorders as the most prominent feature were prospectively evaluated after initiation of the modified Atkins diet. Movement disorders included dystonia, ataxia, myoclonus, and spasticity, either continuous or paroxysmal, triggered by action or exercise. Duration of treatment ranged from 3 months to 16 months. RESULTS: All patients reached mild to moderate ketosis and experienced remarkable improvement in the frequency and severity of paroxysmal movement disorders. Cognitive function also improved subjectively. CONCLUSIONS: The modified Atkins diet is an effective and feasible alternative to the ketogenic diet for the treatment of GLUT1DS-related paroxysmal movement disorders in adolescence and adulthood.

Retention of lysosomal protein CLN5 in the endoplasmic reticulum causes neuronal ceroid lipofuscinosis in Asian sibship.

The neuronal ceroid lipofuscinoses (NCLs) form a group of autosomal recessively inherited neurodegenerative disorders that mainly affect children. Ten NCL forms can be distinguished by age at onset, clinicopathologic features, and genetics. In eight of these forms, the underlying genes have been identified. At present, approximately 10% of all patients do not fall into one of the eight known genetic forms of NCL. We have identified two Asian families with two novel homozygous mutations in the CLN5 gene. In the first Pakistani family, two children developed symptoms of an early juvenile NCL. After exclusion of mutations in genes known to be associated with this age of onset in families from many different countries (CLN1, CLN2, CLN3, CLN6, CLN8 and CLN10) SNP array-based homozygosity mapping led to the identification of a novel homozygous mutation c.1072_1073delTT (p.Leu358AlafsX4) in CLN5. In the second Afghan family, two children developed symptoms of a late infantile NCL. The mutation c.1137G>T (p.Trp379Cys) in CLN5 was identified. The affected children in these families represent the first reported CLN5 patients originating in Asian sibships. Expression analysis showed that mutant p.Leu358AlafsX4 CLN5 is truncated and lacks a used N-glycosylation site at Asn401. The missense mutation p.Trp379Cys affected neither the size nor glycosylation of the CLN5 protein. Double immunofluorescence microscopy showed that while the wild-type CLN5 protein is localized in lysosomes, both mutant CLN5 proteins are retained in the endoplasmic reticulum rather than reaching the lysosome.

Fits, feet and HIV: lessons from a case of coexisting epilepsy and neuropathy in a patient with perinatally acquired HIV-1 infection.

An 18-year-old black African man with well-controlled perinatally acquired HIV-1 was diagnosed in late adolescence with the unrelated diagnoses of Charcot-Marie-Tooth type 1A (CMT1A), epilepsy due to polymicrogyria and subsequently developed severe depression. The CMT1A diagnosis occurred after transfer of care from a local paediatric HIV service to a tertiary paediatric referral centre and was precipitated by recognition of a history and neurological signs not typically associated with perinatal HIV. The case resulted in the establishment of a quarterly combined paediatric HIV and paediatric neurology multidisciplinary team clinic to assess children and adolescents living with HIV with neurological symptoms.

Clinical features, course, and outcomes of a UK cohort of pediatric moyamoya.

OBJECTIVE: To describe characteristics and course of a large UK cohort of children with moyamoya from multiple centers and examine prognostic predictors. METHODS: Retrospective review of case notes/radiology, with use of logistic regression to explore predictors of outcome. RESULTS: Eighty-eight children (median presentation age 5.1 years) were included. Thirty-six presented with arterial ischemic stroke (AIS) and 29 with TIA. Eighty had bilateral and 8 unilateral carotid circulation disease; 29 patients had posterior circulation involvement. Acute infarction was present in 36/176 hemispheres and chronic infarction in 86/176 hemispheres at the index presentation. Sixty-two of 82 with symptomatic presentation had at least one clinical recurrence. Fifty-five patients were treated surgically, with 37 experiencing fewer recurrences after surgery. Outcome was categorized as good using the Recovery and Recurrence Questionnaire in 39/85 patients. On multivariable analysis, presentation with TIA (odds ratio [OR] 0.09, 95% confidence interval [CI] 0.02-0.35), headache (OR 0.10, 95% CI 0.02-0.58), or no symptoms (OR 0.08, 95% CI 0.01-0.68) was less likely to predict poor outcome than AIS presentation. Posterior circulation involvement predicted poor outcome (OR 4.22, 95% CI 1.23-15.53). Surgical revascularization was not a significant predictor of outcome. CONCLUSIONS: Moyamoya is associated with multiple recurrences, progressive arteriopathy, and poor outcome in half of patients, especially with AIS presentation and posterior circulation involvement. Recurrent AIS is rare after surgery. Surgery was not a determinant of overall outcome, likely reflecting surgical case selection and presentation clinical status.

TBC1D24 genotype-phenotype correlation: Epilepsies and other neurologic features.

OBJECTIVE: To evaluate the phenotypic spectrum associated with mutations in TBC1D24. METHODS: We acquired new clinical, EEG, and neuroimaging data of 11 previously unreported and 37 published patients. TBC1D24 mutations, identified through various sequencing methods, can be found online (http://lovd.nl/TBC1D24). RESULTS: Forty-eight patients were included (28 men, 20 women, average age 21 years) from 30 independent families. Eighteen patients (38%) had myoclonic epilepsies. The other patients carried diagnoses of focal (25%), multifocal (2%), generalized (4%), and unclassified epilepsy (6%), and early-onset epileptic encephalopathy (25%). Most patients had drug-resistant epilepsy. We detail EEG, neuroimaging, developmental, and cognitive features, treatment responsiveness, and physical examination. In silico evaluation revealed 7 different highly conserved motifs, with the most common pathogenic mutation located in the first. Neuronal outgrowth assays showed that some TBC1D24 mutations, associated with the most severe TBC1D24-associated disorders, are not necessarily the most disruptive to this gene function. CONCLUSIONS: TBC1D24-related epilepsy syndromes show marked phenotypic pleiotropy, with multisystem involvement and severity spectrum ranging from isolated deafness (not studied here), benign myoclonic epilepsy restricted to childhood with complete seizure control and normal intellect, to early-onset epileptic encephalopathy with severe developmental delay and early death. There is no distinct correlation with mutation type or location yet, but patterns are emerging. Given the phenotypic breadth observed, TBC1D24 mutation screening is indicated in a wide variety of epilepsies. A TBC1D24 consortium was formed to develop further research on this gene and its associated phenotypes.

Postinfectious immune-mediated encephalitis after pediatric herpes simplex encephalitis.

We report a 3-year-old patient who presented a secondary acute neurological deterioration clinically characterized by a partial Kluver-Bucy syndrome, 1 month after the onset of herpes simplex encephalitis. This episode is unlikely due to continuation or resumption of cerebral viral replication but might be related to an immune-inflammatory process. In children, postinfectious immune-mediated encephalitis occurring after HSE are usually clinically characterized by choreoathetoid movements. This type of movement disorder was, however, not observed in this patient. On the basis of this case and a review of the literature, we hypothesize the existence of a spectrum of secondary immune-mediated process triggered by herpes simplex virus cerebral infection ranging from asymptomatic cases with diffuse white matter involvement to secondary acute neurological deteriorations with or without extrapyramidal features.

Pediatric SUNCT Syndrome.

This report describes a 5-year-old male with sudden unilateral headache attacks (2-50 seconds) accompanied by conjunctival injection, lacrimation, and nasal congestion. The episodes occurred without a precipitating factor, never during sleep. Brain imaging was normal. The attacks resolved spontaneously within 5 months. This headache syndrome (short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing) was previously described in two other children aged 10 and 11.

Unilateral cortical necrosis following status epilepticus with hypoglycemia.

Isolated status epilepticus or severe hypoglycemia rarely causes irreversible focal neurologic deficits in children. We describe three children who presented with status epilepticus and prolonged hypoglycemia resulting in hemiplegia due to unilateral hemispheric damage. The non-vascular cortical topography of the lesions is consistent with selective neuronal necrosis, confirmed by histopathology in one patient. This suggests increased neuronal vulnerability to necrosis secondary to energy failure resulting from combination of hypoglycemia and status epilepticus.

Gait control in spinal palsy.

Developmental motor impairment with lower limb spasticity most commonly corresponds to cerebral palsy of the spastic diplegia type. Here we describe a 4-year-old girl whose locomotor phenotype reflects early cortico-spinal lesion at the spinal level. This child has developmental spastic paraparesis secondary to D4-D8 cord compression. We analysed her gait using the ELITE optoelectronic system and compared it to that of six normal age-matched controls and six age-matched children with leucomalacic spastic diplegia. Gait characteristics of the patient included preservation of head orientation and arm swing similar to findings in normal controls and contrasting with children with spastic diplegia. She also had truncal instability and displayed lack of selectivity in lower limb movement as in spastic diplegia and in contrast with normal controls. This may reflect differences in locomotor control between developmental spasticity of cerebral and spinal origin. The latter might correspond to spinal palsy defined as abnormal movement and posture secondary to non-progressive pathological processes affecting the immature spinal cord.

Motor strategies in standing up in leukomalacic spastic diplegia.

In spastic diplegia impaired postural control jeopardizes the organization of whole-body movements. We studied segmental motor patterns involved in standing up from a supine position in ten children with spastic diplegia associated with periventricular leukomalacia and 14 unimpaired children using a visual analysis scale previously devised for developmental research. This approach examines specific movement patterns in upper limbs, axis and lower limbs. We found that children with spastic diplegia use movement patterns described in normal children but with markedly reduced intra- and interindividual variability. One previously undescribed stereotyped lower limb pattern was observed in four patients. This approach can systematically characterize the limited repertoire of movement in patients with spastic diplegia and therefore contribute to a better understanding of motor control.

Pediatric phantom vision (Charles Bonnet) syndrome.

Visual symptomatology in childhood often presents diagnostic difficulties. Recurrent paroxysmal visual complaints, although typically associated with migraine, may also signal other disorders. We describe a 9-year-old partially sighted male with paroxysmal zoopsias resulting from Charles Bonnet syndrome. This condition is characterized by paroxysmal visual hallucinations occurring in patients with chronic visual impairment, akin to the phantom-limb phenomenon. This pediatric case is the fourth report of this condition. We have reviewed the other cases.

Nonsurgical cerebellar mutism (anarthria) in two children.

Cerebellar mutism (anarthria) is a well-described complication of posterior fossa tumor resection. It is accompanied by a characteristic behavior including irritability and autistic features. This syndrome is typically reversible within days to months. Underlying pathophysiology is unknown. We describe two children who presented with a similar clinical finding after nonsurgical cerebellar involvement, hemolytic-uremic syndrome in one and cerebellitis in the other. Postmortem pathologic findings in the first patient indicated cerebellar ischemic necrosis. Single-photon emission computed tomography in the second patient revealed diffuse cerebellar hypoperfusion with no supratentorial abnormalities, refuting a phenomenon of diaschisis between cerebellar and frontal connections. These findings confirm that this clinical syndrome may occur in a nonsurgical, nontraumatic context. They are consistent with recent integrative hypotheses explaining cerebellar anarthria.

Motor strategies in standing up in children with hemiplegia.

In spastic hemiplegia, the organization of whole body movements is impaired by deficient postural control. We studied segmental motor patterns involved in standing up from supine position in 15 children with spastic hemiplegic cerebral palsy and 14 unimpaired children using a visual analysis scale previously validated for developmental research. This approach examines specific movement patterns in upper limbs, axis, and lower limbs. We found that children with hemiplegia use movement patterns described in normal children but with reduced interindividual variability and a significant preponderance of asymmetric patterns. One previously undescribed stereotyped lower limb pattern was observed in two children with spastic hemiplegia. Emergence of these patterns is consistent with the referent body image theory. This approach can systematically characterize the limited repertoire of movement in patients with disorders of movement and posture and therefore contribute to a better understanding of motor control. The approach may guide management proposals with particular reference to variability and symmetry and might be used as a follow-up tool.

Cervical myelitis from herpes simplex virus type 1.

Although subacute ascending paralysis without sensory involvement is typically evocative of Guillain-Barré syndrome, it can alternatively be due to infection or inflammation of the spinal cord. We describe a 16-month-old female who presented with ascending flaccid paresis after an upper respiratory tract infection. She then developed signs of upper motor neuron involvement of the lower limbs associated with upper motor neuron involvement of the upper limbs. Motor nerve conduction and electromyographic studies of upper limbs demonstrated anterior horn cell involvement. Neuroimaging was consistent with cervical myelitis, and cerebrospinal fluid polymerase chain reaction was positive for herpesvirus-1. Although association with the primary infection of the respiratory tract may be fortuitous, possible neurotropic or hematogenous spread of herpesvirus-1 to the cervical spinal cord cannot be excluded. She then developed signs of upper motor neuron involvement of the lower limbs associatred with lower motor neuron involvement of the upper limbs [corrected].

Benign intracranial hypertension: atypical presentation of Miller Fisher syndrome?

Acute ocular paresis, nausea, vomiting, and headaches associated with high intracranial pressure without obvious intracranial pathology are typical features of benign intracranial hypertension. We describe two young children whose presentation, initially suggestive of idiopathic or benign intracranial hypertension, evolved to comprise ophthalmoplegia, ataxia, and areflexia. This triad characterizes Miller Fisher syndrome, a clinical variant of Guillain-Barré syndrome that occurs rarely among children. In both patients, this diagnosis was supported by the clinical course and neurophysiologic findings. Plasma serology was positive for Campylobacter jejuni and anti-GQ1b antibodies in one patient and for antimyelin antibodies in the other. This report of two children with Miller Fisher syndrome presenting with intracranial hypertension adds to the findings for a similar patient treated previously, which raises the question concerning the possible role or contribution of benign intracranial hypertension in Miller Fisher syndrome.