Brahim Tabarki

Acute transverse myelitis in children: Clinical course and prognostic factors

The objective of this study was to describe the clinical course of acute transverse myelitis in children, to identify prognostic factors, and to compare our findings with published data. Twenty-four children, aged 2 to 14 years and admitted with a diagnosis of acute transverse myelitis, were studied. Clinical features and results of investigations were collected at admission and during the course of the disease. Motor, sphincter, and global outcomes were compared with those in the main adult and pediatric series. During the initial phase, the most common presenting symptoms were pain (88%) and fever (58%). Motor loss preceded sphincter dysfunction in two thirds of patients and became bilateral in half of the patients. When maximal deficit was achieved (plateau), the patients presented a combination of sensory, motor, and sphincter dysfunctions without radicular involvement. The motor loss consistently involved the lower limbs but was inconsistent and moderate in the upper limbs. The mean duration of the plateau was 1 week. The recovery phase was characterized by a progressive improvement of all deficits. Sphincter dysfunction improved more slowly than did the other deficits. A full recovery was achieved by 31% of the patients; minimal sequelae were present in 25% and mild to severe sequelae in 44%. An unfavorable outcome was associated with complete paraplegia (P = .03) and/or a time to maximal deficit shorter than 24 hours (P = .005). A favorable outcome was associated with a plateau shorter than 8 days ( P = .03), the presence of supraspinal symptoms (P = .01), and a time to independent walking shorter than 1 month (P = .01). The course of acute transverse myelitis in children proceeds through three stages, an initial phase, a plateau, and a recovery phase, each characterized by specific clinical features. The global outcome was favorable in 56% of patients. Several prognostic factors were identified. (J Child Neurol 2003;18:401—406).

Biotin-responsive basal ganglia disease revisited: Clinical, radiologic, and genetic findings

Objective: To investigate the clinical, genetic, and neuroradiologic data of biotin-responsive basal ganglia disease (BBGD) and clarify the disease spectrum. Methods: We first investigated all patients attending our Division of Pediatric Neurology with a genetically proven diagnosis of BBGD between 2009 and 2011. All patients underwent a detailed medical history and clinical examination, extensive laboratory investigations including genetic tests, and brain MRI. Finally, we conducted a systematic review of the literature. Results: We enrolled 10 patients meeting the diagnostic criteria for BBGD, and analyzed the data on 14 patients from 4 previous reports. The BBGD occurred predominantly in preschool/school-aged patients in the Saudi population, but it was also observed in other ethnic groups. The typical clinical picture consisted of recurrent subacute encephalopathy leading to coma, seizures, and extrapyramidal manifestations. The brain MRI typically showed symmetric and bilateral lesions in the caudate nucleus and putamen, infra- and supratentorial brain cortex, and in the brainstem. Vasogenic edema characterized the acute crises as demonstrated by diffusion-weighted imaging/apparent diffusion coefficient MRI. Atrophy and gliosis in the affected regions were observed in patients with chronic disease. Early treatment with a combination of biotin and thiamine resulted in clinical and neuroradiologic improvement. Death and neurologic sequelae including dystonia, mental retardation, and epilepsy were observed in those who were not treated or were treated late. Conclusion: BBGD is an underdiagnosed pan-ethnic treatable condition. Clinicians caring for patients with unexplained encephalopathy and neuroimaging showing vasogenic edema in the bilateral putamen and caudate nuclei, infra- and supratentorial cortex, and brainstem should consider this disorder early in the hospital course because a therapeutic trial with biotin and thiamine can be lifesaving.

Kawasaki disease with predominant central nervous system involvement

A 4-year-old female was hospitalized with clinical and electroencephalographic evidence of acute encephalopathy. Five days later the classic signs of Kawasaki disease appeared. The neurologic outcome in this female was poor despite early treatment with immunoglobulin. Like many other vasculitidies, Kawasaki disease can have predominant neurologic symptoms as the initial presentation and during the subsequent evolution of the condition.

Childhood dermatomyositis: Clinical course of 36 patients treated with low doses of corticosteroids

Thirty-six patients with juvenile dermatomyositis, seen consecutively between 1983 and 1996 and treated initially with low doses of corticosteroids (prednisolone 1 mg/kg/day), were studied retrospectively to evaluate their long-term evolution and to identify factors predictive of the functional outcome. After a mean follow-up of 4.9 years, 28 (78%) of the patients were well without functional impairment; five patients had inactive disease but with persisting disabilities; and three patients had active disease despite several years of treatment. Fifteen children (42%) developed dystrophic calcifications which, in five of these patients, interfered with functions. These patients treated for juvenile dermatomyositis with a low dose corticosteroid regimen had an evolution identical to that of the published series of patients treated with higher doses and probably had a better quality of life. The best predictors of good functional recovery and minimal calcinosis were early treatment after the onset of symptoms and low creatine kinase serum level at the time of diagnosis.

Characterizing the morbid genome of ciliopathies

BackgroundCiliopathies are clinically diverse disorders of the primary cilium. Remarkable progress has been made in understanding the molecular basis of these genetically heterogeneous conditions; however, our knowledge of their morbid genome, pleiotropy, and variable expressivity remains incomplete.ResultsWe applied genomic approaches on a large patient cohort of 371 affected individuals from 265 families, with phenotypes that span the entire ciliopathy spectrum. Likely causal mutations in previously described ciliopathy genes were identified in 85% (225/265) of the families, adding 32 novel alleles. Consistent with a fully penetrant model for these genes, we found no significant difference in their “mutation load” beyond the causal variants between our ciliopathy cohort and a control non-ciliopathy cohort. Genomic analysis of our cohort further identified mutations in a novel morbid gene TXNDC15, encoding a thiol isomerase, based on independent loss of function mutations in individuals with a consistent ciliopathy phenotype (Meckel-Gruber syndrome) and a functional effect of its deficiency on ciliary signaling. Our study also highlighted seven novel candidate genes (TRAPPC3, EXOC3L2, FAM98C, C17orf61, LRRCC1, NEK4, and CELSR2) some of which have established links to ciliogenesis. Finally, we show that the morbid genome of ciliopathies encompasses many founder mutations, the combined carrier frequency of which accounts for a high disease burden in the study population.ConclusionsOur study increases our understanding of the morbid genome of ciliopathies. We also provide the strongest evidence, to date, in support of the classical Mendelian inheritance of Bardet-Biedl syndrome and other ciliopathies.

RTTN Mutations Cause Primary Microcephaly and Primordial Dwarfism in Humans

Primary microcephaly is a developmental brain anomaly that results from defective proliferation of neuroprogenitors in the germinal periventricular zone. More than a dozen genes are known to be mutated in autosomal-recessive primary microcephaly in isolation or in association with a more generalized growth deficiency (microcephalic primordial dwarfism), but the genetic heterogeneity is probably more extensive. In a research protocol involving autozygome mapping and exome sequencing, we recruited a multiplex consanguineous family who is affected by severe microcephalic primordial dwarfism and tested negative on clinical exome sequencing. Two candidate autozygous intervals were identified, and the second round of exome sequencing revealed a single intronic variant therein (c.2885+8A>G [p.Ser963(∗)] in RTTN exon 23). RT-PCR confirmed that this change creates a cryptic splice donor and thus causes retention of the intervening 7 bp of the intron and leads to premature truncation. On the basis of this finding, we reanalyzed the exome file of a second consanguineous family affected by a similar phenotype and identified another homozygous change in RTTN as the likely causal mutation. Combined linkage analysis of the two families confirmed that RTTN maps to the only significant linkage peak. Finally, through international collaboration, a Canadian multiplex family affected by microcephalic primordial dwarfism and biallelic mutation of RTTN was identified. Our results expand the phenotype of RTTN-related disorders, hitherto limited to polymicrogyria, to include microcephalic primordial dwarfism with a complex brain phenotype involving simplified gyration.

KIAA0556 is a novel ciliary basal body component mutated in Joubert syndrome

BackgroundJoubert syndrome (JBTS) and related disorders are defined by cerebellar malformation (molar tooth sign), together with neurological symptoms of variable expressivity. The ciliary basis of Joubert syndrome related disorders frequently extends the phenotype to tissues such as the eye, kidney, skeleton and craniofacial structures.ResultsUsing autozygome and exome analyses, we identified a null mutation in KIAA0556 in a multiplex consanguineous family with hallmark features of mild Joubert syndrome. Patient-derived fibroblasts displayed reduced ciliogenesis potential and abnormally elongated cilia. Investigation of disease pathophysiology revealed that Kiaa0556-/- null mice possess a Joubert syndrome-associated brain-restricted phenotype. Functional studies in Caenorhabditis elegans nematodes and cultured human cells support a conserved ciliary role for KIAA0556 linked to microtubule regulation. First, nematode KIAA0556 is expressed almost exclusively in ciliated cells, and the worm and human KIAA0556 proteins are enriched at the ciliary base. Second, C. elegans KIAA0056 regulates ciliary A-tubule number and genetically interacts with an ARL13B (JBTS8) orthologue to control cilium integrity. Third, human KIAA0556 binds to microtubules in vitro and appears to stabilise microtubule networks when overexpressed. Finally, human KIAA0556 biochemically interacts with ciliary proteins and p60/p80 katanins. The latter form a microtubule-severing enzyme complex that regulates microtubule dynamics as well as ciliary functions.ConclusionsWe have identified KIAA0556 as a novel microtubule-associated ciliary base protein mutated in Joubert syndrome. Consistent with the mild patient phenotype, our nematode, mice and human cell data support the notion that KIAA0556 has a relatively subtle and variable cilia-related function, which we propose is related to microtubule regulation.

Severe early-onset epileptic encephalopathy due to mutations in the KCNA2 gene: Expansion of the genotypic and phenotypic spectrum.

BACKGROUND Recently, de novo loss- or gain-of-function mutations in the KCNA2 gene; have been described in individuals with epileptic encephalopathy, ataxia or intellectual disability. CASE DESCRIPTION In this report, we describe a further case of KCNA2-early-onset epileptic encephalopathy. The patient presented since birth with intractable seizures, progressive microcephaly, developmental delay, and progressive brain atrophy. Whole-exome sequencing showed a novel de novo mutation in the KCNA2 gene: c.1120A > G (p.Thr374Ala). CONCLUSION This case expands the genotypic and phenotypic disease spectrum of this genetic form of KCNA2-early onset epileptic encephalopathy.

Familial spastic paraplegia as the presenting manifestation in patients with purine nucleoside phosphorylase deficiency.

We report two siblings with purine nucleoside phosphorylase deficiency revealed by isolated spastic paraplegia, whereas symptoms of immune deficiency did not become apparent until 3 years of age. As the concurrence of immunodeficiency and neurologic problems strongly suggests the diagnosis of purine nucleoside phosphorylase deficiency, special attention should be paid to counts of lymphocytes in any infant with spastic paraplegia. (J Child Neurol 2003;18:140—141).

Further Delineation of the ALG9-CDG Phenotype

ALG9-CDG is one of the less frequently reported types of CDG. Here, we summarize the features of six patients with ALG9-CDG reported in the literature and report the features of four additional patients. The patients presented with drug-resistant infantile epilepsy, hypotonia, dysmorphic features, failure to thrive, global developmental disability, and skeletal dysplasia. One patient presented with nonimmune hydrops fetalis. A brain MRI revealed global atrophy with delayed myelination. Exome sequencing identified a novel homozygous mutation c.1075G>A, p.E359K of the ALG9 gene. The results of our analysis of these patients expand the knowledge of ALG9-CDG phenotype.