Case Report: A rare treatable metabolic syndrome (Brown-Vialetto-Van Laere syndrome) masquerading as chronic inflammatory demyelinating polyneuropathy from Saudi Arabia.

Background: Brown-Vialetto-Van Laere (BVVL) syndrome is an extremely rare autosomal recessive progressive motoneuron disease that is caused by a defect in the riboflavin transporter genes SLC52A2 and SLC52A3. BVVL syndrome has a variable age of presentation, and it is characterized by progressive auditory neuropathy, bulbar palsy, stridor, muscle weakness, and respiratory compromise secondary to diaphragmatic and vocal cord paralysis. BVVL syndrome has a poor prognosis in the absence of treatment, including morbidity with quadriparesis and sensorineural hearing loss, with mortality in the younger age group. Early administration of riboflavin is associated with prolonged survival, low morbidity, and reversal of some clinical manifestations. Case presentation: We describe an 18-month-old male infant with progressive pontobulbar palsy, loss of developmental milestones, and a clinical picture suggestive of chronic inflammatory demyelinating neuropathy. A nerve conduction study revealed axonal neuropathy, while molecular analysis revealed a homozygous mutation in one of the riboflavin transporter genes, SLC52A3, confirming BVVL syndrome. The patient needed long-term respiratory support and a gastrostomy tube to support feeding. With high-dose riboflavin supplementation, he experienced moderate recovery of motor function. Conclusion: This report highlights the importance of considering BVVL syndrome in any patient who presents with the clinical phenotype of pontobulbar palsy and peripheral axonal neuropathy, as early riboflavin treatment may improve or halt disease progression, thus reducing the associated mortality and morbidity.

Pattern and etiology of early childhood epilepsy: An Experience at a tertiary care University Center.

OBJECTIVES: To investigate seizure characteristics, types, and define the etiology of epilepsy in children aged ≤2 years using the 2017 ILAE classification. METHODS: A retrospective chart review was conducted at King Khalid University Hospital, King Saud University Medical City, Riyadh, Kingdom of Saudi Arabia for children below 2 years of age diagnosed with epilepsy, and on anti-seizure medications from January 2017 - December 2018. The collected data involved detailed information on the patients' seizure, electroclinical, neuroimaging, laboratory evaluations, and underlying etiology. RESULTS: One- hundred and fifty patients were included in the study and classified according to etiology into: genetic (43, 28.7%), structural (41, 27.3%), metabolic (10, 6.7%), infectious (8, 5.3%), immune-mediated (1, 0.7%) and unknown (47, 31.3%) groups. The most common seizure types were generalized epilepsy, among which generalized tonic-clonic seizures occurred in 56 (37%) patients, followed by tonic seizures in 31 (21%), infantile spasm in 19 (13%), myoclonic seizures in 4 (2.7%), atonic seizures in 6 (4%), and focal seizures in 33 (22%) patients. Global developmental delay and abnormalities in both neurologic exam and neuroimaging were more common in the structural and genetic groups. Electroencephalography was abnormal in 82 (55%) patients, including the majority of the structural group (26, 63.4%). CONCLUSION: The etiology of epilepsy in this cohort remains undetermined (unknown) in a large proportion of cases, followed by genetic and structural causes. This result added to the published international data about epilepsy in the first 2-years of life.

Hypermanganesemia with Dystonia Type 2: A Potentially Treatable Neurodegenerative Disorder: A Case Series in a Tertiary University Hospital.

IMPORTANCE: Hypermanganesemia with dystonia type 2 is a rare autosomal recessive neurodegenerative disorder characterized by the loss of previously acquired milestones, dystonia, parkinsonian features, a high serum manganese level, and characteristic neuroimaging findings such as bilateral and symmetrically increased T1 and decreased T2/fluid-attenuated inversion recovery signal intensity in the basal ganglia. This condition is secondary to a mutation in the SLC39A14 gene. OBJECTIVE: To present a series of three cases of hypermanganesemia with dystonia type 2, which was genetically confirmed secondary to a mutation in the SLC39A14 gene, and to describe the treatment and clinical course in these cases. DESIGN: A retrospective case series. SETTING: University, Tertiary hospital. PARTICIPANTS: Three unrelated pediatric patients with hypermanganesemia with dystonia type 2, genetically confirmed to be secondary to a mutation in the SLC39A14 gene. EXPOSURES: Chelation therapy using calcium disodium edetate. MAIN OUTCOME(S) AND MEASURE(S): The response to chelation therapy based on clinical improvements in motor and cognition developments. RESULTS: All three patients were started on chelation therapy using calcium disodium edetate, and two of them showed an improvement in their clinical course. The chelation therapy could alter the course of the disease and prevent deterioration in the clinical setting. CONCLUSIONS AND RELEVANCE: Early diagnosis and intervention with chelating agents, such as calcium disodium edetate, will help change the outcome in patients with hypermanganesemia with dystonia type 2. This finding highlights the importance of early diagnosis and treatment in improving the outcomes of patients with treatable neurodegenerative disorders.

Childhood absence epilepsy: Electro-clinical manifestations, treatment options, and outcome in a tertiary educational center.

Purpose and Background: To evaluate the electro-clinical manifestations and outcomes of children with absence epilepsy at a tertiary center in Saudi Arabia. Methods: This retrospective study reviewed the medical and EEG records of patients who were diagnosed to have CAE as per the International League Against Epilepsy (ILAE) definition for CAE. The study was conducted in the pediatric neurology clinic of King Khalid University Hospital, King Saud University Medical City, Riyadh, Saudi Arabia, between January 2000 and December 2019. Patients who did not meet (ILAE) criteria, lost follow-up, and those who did not receive treatment at KKUH were excluded. Data regarding the patient's disease, electro-clinical manifestations, anti-seizure medication response, and outcomes were collected. Results: A total of 35 patients, with an average age at diagnosis of 7 ± 2.1 y, were included in the study; among them, 51.4% were female and approximately 48.6% presented with a family history of epilepsy. Regarding clinical features, all patients experienced staring and altered awareness, 94.2% had less than 20 spells per day at the time of diagnosis, and 65.7% were provoked by the hyperventilation test. Regarding EEG findings, all patients had bilateral, symmetrical, and synchronous discharges in the form of regular 3 Hz spike-and-wave complexes, and 94.3% had a generalized initial ictal discharge. Also, 22.8% had eye fluttering with electrographic seizures. Ethosuximide (ESM) was used as the drug of choice in 45.7% of the patients. Regarding clinical outcomes, 94.3% had their disease clinically controlled, and 80% had a normalized EEG after few months of starting anti-seizure medication. Finally, 37.2% experienced complete remission of epilepsy after 3-5 y; however, one patient developed juvenile myoclonic epilepsy. Conclusion: This study described the electro-clinical manifestations of patients with childhood absence epilepsy and outcomes. Furthermore, early diagnosis and prompt treatment of childhood absence epilepsy improve treatment outcomes.

Acute Necrotizing Encephalopathy of Childhood: A Multicenter Experience in Saudi Arabia.

Background: Acute necrotizing encephalopathy of childhood (ANEC) is a rapidly progressing encephalopathy characterized by fever, depressed level of consciousness, and seizures. Diagnosis depends on clinical presentation and characteristic neuroimaging findings of abnormal signal intensity involving the thalami as well as the supra and infra-tentorial areas. Treatment modalities are not well-established; empirical treatment with antibiotics and antiviral agents is the initial step, followed by steroids and immunoglobulin, as well as supportive care. Patients with ANEC have a variable prognosis, but mortality is very high. Methods: A retrospective chart review of patients diagnosed with ANEC in five tertiary centers from January 2015 to October 2018 was performed. Clinical and radiological findings, as well as the therapeutic approach and outcomes, were described. Results: Twelve children were included ranging in age from 10 months to 6 years. All patients presented with preceding febrile illness, altered level of consciousness, and seizure. Radiological features showed abnormal signals in the thalami, and five patients (41.7%) had brainstem involvement. All patients received empirical treatment with antibiotics and antiviral agents. Ten patients (83.3%) received intravenous immunoglobulin (IVIG) and IV Methylprednisolone therapy. Outcomes were variable ranging from good outcomes with minimal neurological deficits to poor outcomes and death in 25% of cases. Conclusion: ANEC is a rare fulminant disease in children. The treatment is challenging. Early interventions with the use of IVIG and IV Methylprednisolone may change the outcome; however, further studies are needed to establish a consensus guideline for the management.

Pediatric intracranial hypertension. Experience from 2 Tertiary Centers.

OBJECTIVE: To review the experience of 2 tertiary centers in Saudi Arabia with intracranial hypertension (IH) in the pediatric population. METHODS: We retrospectively reviewed and analyzed pediatric patients diagnosed with IH from June 2002 to May 2017 in 2 institutes. RESULTS: We identified 53 patients (30 females and 23 males) with a mean age of 7 years at the time of presentation. Among them, 41 patients were younger than 12 years, and 12 were older. Obese and overweight patients constituted 27.00% (n = 14) of all cases, 8 (66.7%) of whom were older than 12 years. The most common presenting feature was papilledema followed by headache. Vitamin D deficiency, which constituted the most common associated condition, was identified in 12 (22.6%) patients. Acetazolamide was the treatment option in 98.11% of patients, and only 5.7% underwent surgical interventions. The length of follow-up ranged from 6 months to 8 years. CONCLUSION: Intracranial hypertension is rare in children and commonly seen in overweight females older than 12 years similar to adults. Patients younger than 12 years tend to develop secondary IH. More studies are needed to characterize the clinical presentation and guide the management plan.

PANDAS versus Hashimoto`s encephalopathy: a diagnostic dilemma in a Saudi girl.

Paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) is a rare recently recognised clinical syndrome with common presentations that include tics, Tourette's-like syndrome or obsessive-compulsive disorder. It is associated with various behavioural and psychiatric manifestations in children, such as separation anxiety disorder, body dysmorphic disorder, and attention deficit hyperactivity disorder. Steroid responsive encephalopathy with autoimmune thyroiditis (SREAT) is a rare disorder in children associated also with various movement disorders and neuropsychiatric manifestations. The present report describes a previously healthy 10-year-old girl who presented with motor tics, visual hallucination, separation anxiety, and emotional liability. Her workup showed an evidence of Hashimoto's thyroiditis on laboratory results, in addition to the elevation of antistreptolysin O titre (ASO). Based on this, a diagnosis of SREAT was made, and she was given courses of methylprednisolone with inadequate response. Then, the possibility of PANDAS was considered, and she responded to multiple courses of antibiotics with abate of symptoms after a course of intravenous immunoglobulin combined with monthly benzathine penicillin injections. To the best of our knowledge, this is the first reported case of PANDAS associated with autoimmune thyroiditis causing such diagnostic dilemma.

Autozygome and high throughput confirmation of disease genes candidacy.

PURPOSE: Establishing links between Mendelian phenotypes and genes enables the proper interpretation of variants therein. Autozygome, a rich source of homozygous variants, has been successfully utilized for the high throughput identification of novel autosomal recessive disease genes. Here, we highlight the utility of the autozygome for the high throughput confirmation of previously published tentative links to diseases. METHODS: Autozygome and exome analysis of patients with suspected Mendelian phenotypes. All variants were classified according to the American College of Medical Genetics and Genomics guidelines. RESULTS: We highlight 30 published candidate genes (ACTL6B, ADAM22, AGTPBP1, APC, C12orf4, C3orf17 (NEPRO), CENPF, CNPY3, COL27A1, DMBX1, FUT8, GOLGA2, KIAA0556, LENG8, MCIDAS, MTMR9, MYH11, QRSL1, RUBCN, SLC25A42, SLC9A1, TBXT, TFG, THUMPD1, TRAF3IP2, UFC1, UFM1, WDR81, XRCC2, ZAK) in which we identified homozygous likely deleterious variants in patients with compatible phenotypes. We also identified homozygous likely deleterious variants in 18 published candidate genes (ABCA2, ARL6IP1, ATP8A2, CDK9, CNKSR1, DGAT1, DMXL2, GEMIN4, HCN2, HCRT, MYO9A, PARS2, PLOD3, PREPL, SCLT1, STX3, TXNRD2, WIPI2) although the associated phenotypes are sufficiently different from the original reports that they represent phenotypic expansion or potentially distinct allelic disorders. CONCLUSIONS: Our results should facilitate the timely relabeling of these candidate disease genes in relevant databases to improve the yield of clinical genomic sequencing.

The many faces of peroxisomal disorders: Lessons from a large Arab cohort.

Defects in the peroxisomes biogenesis and/or function result in peroxisomal disorders. In this study, we describe the largest Arab cohort to date (72 families) of clinically, biochemically and molecularly characterized patients with peroxisomal disorders. At the molecular level, we identified 43 disease-causing variants, half of which are novel. The founder nature of many of the variants allowed us to calculate the minimum disease burden for these disorders in our population ~1:30 000, which is much higher than previous estimates in other populations. Clinically, we found an interesting trend toward genotype/phenotype correlation in terms of long-term survival. Nearly half (40/75) of our peroxisomal disorders patients had documented survival beyond 1 year of age. Most unusual among the long-term survivors was a multiplex family in which the affected members presented as adults with non-specific intellectual disability and epilepsy. Other unusual presentations included the very recently described peroxisomal fatty acyl-CoA reductase 1 disorder as well as CRD, spastic paraparesis, white matter (CRSPW) syndrome. We conclude that peroxisomal disorders are highly heterogeneous in their clinical presentation. Our data also confirm the demonstration that milder forms of Zellweger spectrum disorders cannot be ruled out by the "gold standard" very long chain fatty acids assay, which highlights the value of a genomics-first approach in these cases.

Auto-immune anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis: three case reports.

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a recently identified auto-immune disorder characterised by severe memory deficit, a decreased level of consciousness, seizures, autonomic dysfunction and movement disorders. Three girls with the disorder are reported; they were aged 4 years, 5 years and 10 months. The 10-month-old infant who is one of the youngest patients reported with anti-NMDAR encephalitis worldwide, had MRI features suggestive of herpes simplex encephalitis (known to trigger anti-NMDAR encephalitis), but CSF PCR for herpes simplex was negative. All the patients presented with seizures, behavioural change, regression of speech, dystonia and choreo-athetosis. Anti-NMDAR antibodies were detected in all patients' sera and cerebrospinal fluid (CSF). Intravenous immunoglobulin, corticosteroids and rituximab were administered at different intervals. Cases 1 and 2 made a full recovery, but case 3 has mild motor and speech delay. Patients who present with encephalopathy, seizures and movement disorders should be tested for anti-NMDAR antibodies in serum and CSF in addition to being screened for herpes simplex encephalitis.

Klippel-Trenaunay and Sturge-Weber overlapping syndrome in a Saudi boy.

Sturge-Weber Syndrome (SWS) is a rare, sporadic neurocutaneous disorder. It is typically characterized by unilateral, posterior leptomeningeal angiomas that calcify, glaucoma, and facial portwine tains. Klippel-Trenaunay syndrome (KTS) is a rare congenital syndrome characterized by ipsilateral cutaneous capillary malformations, venous varicosities, and bony or soft tissue overgrowth of the affected limbs. The clinical, neuroradiological features as well as the outcome of a Saudi boy who was referred to the Division of Pediatric Neurology, King Saud University Medical City, Riyadh, Saudi Arabia, with intractable focal seizure and left-sided hemiparesis who was eventually diagnosed with combined SWS and KTS is described here. The rare coexistence of SWS and KTS should be suspected in a child presenting with neurological manifestation such as epilepsy, mental sub normality, or hemiparesis, with port-wine staining or capillary hemangioma and enlarged limbs. Awareness may help in improving the quality of life and survival of these patients.

A novel syndrome of Klippel-Feil anomaly, myopathy, and characteristic facies is linked to a null mutation in MYO18B.

BACKGROUND: Klippel-Feil anomaly (KFA) can be seen in a number of syndromes. We describe an apparently novel syndromic association with KFA. METHODS: Clinical phenotyping of two consanguineous families followed by combined autozygome/exome analysis. RESULTS: Two patients from two apparently unrelated families shared a strikingly similar phenotype characterised by KFA, myopathy, mild short stature, microcephaly, and distinctive facies. They shared a single founder autozygous interval in which whole exome sequencing revealed a truncating mutation in MYO18B. There was virtually complete loss of the transcript in peripheral blood, indicative of nonsense-mediated decay. Electron microscopy of muscle confirms abnormal myosin filaments with accompanying myopathic changes. CONCLUSIONS: Deficiency of MYO18B is linked to a novel developmental disorder which combines KFA with myopathy. This suggests a widespread developmental role for this gene in humans, as observed for its murine ortholog.

Accelerating novel candidate gene discovery in neurogenetic disorders via whole-exome sequencing of prescreened multiplex consanguineous families.

Our knowledge of disease genes in neurological disorders is incomplete. With the aim of closing this gap, we performed whole-exome sequencing on 143 multiplex consanguineous families in whom known disease genes had been excluded by autozygosity mapping and candidate gene analysis. This prescreening step led to the identification of 69 recessive genes not previously associated with disease, of which 33 are here described (SPDL1, TUBA3E, INO80, NID1, TSEN15, DMBX1, CLHC1, C12orf4, WDR93, ST7, MATN4, SEC24D, PCDHB4, PTPN23, TAF6, TBCK, FAM177A1, KIAA1109, MTSS1L, XIRP1, KCTD3, CHAF1B, ARV1, ISCA2, PTRH2, GEMIN4, MYOCD, PDPR, DPH1, NUP107, TMEM92, EPB41L4A, and FAM120AOS). We also encountered instances in which the phenotype departed significantly from the established clinical presentation of a known disease gene. Overall, a likely causal mutation was identified in >73% of our cases. This study contributes to the global effort toward a full compendium of disease genes affecting brain function.

The clinical utility of molecular karyotyping for neurocognitive phenotypes in a consanguineous population.

PURPOSE: Molecular karyotyping has rapidly become the test of choice in patients with neurocognitive phenotypes, but studies of its clinical utility have largely been limited to outbred populations. In consanguineous populations, single-gene recessive causes of neurocognitive phenotypes are expected to account for a relatively high percentage of cases, thus diminishing the yield of molecular karyotyping. The aim of this study was to test the clinical yield of molecular karyotyping in the highly consanguineous population of Saudi Arabia. METHODS: We have reviewed the data of 584 patients with neurocognitive phenotypes (mainly referred from pediatric neurology clinics), all evaluated by a single clinical geneticist. RESULTS: At least 21% of tested cases had chromosomal aberrations that are likely disease-causing. These changes include both known and novel deletion syndromes. The higher yield of molecular karyotyping in this study as compared with the commonly cited 11% can be explained by our ability to efficiently identify single-gene disorders, thus enriching the samples that underwent molecular karyotyping for de novo chromosomal aberrations. We show that we were able to identify a causal mutation in 37% of cases on a clinical basis with the help of autozygome analysis, thus bypassing the need for molecular karyotyping. CONCLUSION: Our study confirms the clinical utility of molecular karyotyping even in highly consanguineous populations.

NECAP1 loss of function leads to a severe infantile epileptic encephalopathy.

BACKGROUND: Epileptic encephalopathy is a broad clinical category that is highly heterogeneous genetically. OBJECTIVE: To describe a multiplex extended consanguineous family that defines a molecularly novel subtype of early infantile epileptic encephalopathy. METHODS: Autozygosity mapping and exome sequencing for the identification of the causal mutation. This was followed by expression analysis of the candidate gene. RESULTS: In an extended multigenerational family with six affected individuals, a single novel disease locus was identified on chromosome 12p13.31-p13.2. Within that locus, the only deleterious novel exomic variant was a homozygous truncating mutation in NECAP1, encoding a clathrin-accessory protein. The mutation was confirmed to trigger nonsense-mediated decay. Consistent with previous reports, we show that NECAP1 is highly enriched in the central nervous system. CONCLUSIONS: NECAP1 is known to regulate clathrin-mediated endocytosis in synapses. The mutation we report here links for the first time this trafficking pathway in early infantile epileptic encephalopathy.

The neurologic aspects of hypomelanosis of Ito: Case report and review of the literature.

The term hypomelanosis of Ito (HI) is applied to individuals with skin hypopigmentation along the lines of Blaschko. Although it was originally described as a purely cutaneous disease, subsequent studies describing HI reported a 33% to 94% association with multiple extracutaneous manifestations, mostly of the central nervous and musculoskeletal systems. This leads to characterization of HI as a neurocutaneous disorder. We report a 10-year-old boy who presented with constellation of multiple congenital anomalies including facial dysmorphism, skin hypopigmentation, musculoskeletal, and nervous system abnormalities. The latter manifested as hypotonia, generalized seizures, and mild mental retardation. Cranial magnetic resonance imaging revealed normal finding initially, however; follow-up diffusion weighted images were suggestive of a possible iron accumulation. The facial phenotype coupled with the bilateral globus pallidi lesions were never been reported in association with HI. Thus, our patient represents a possible novel example of HI.

New findings in a global approach to dissect the whole phenotype of PLA2G6 gene mutations.

Mutations in PLA2G6 gene have variable phenotypic outcome including infantile neuroaxonal dystrophy, atypical neuroaxonal dystrophy, idiopathic neurodegeneration with brain iron accumulation and Karak syndrome. The cause of this phenotypic variation is so far unknown which impairs both genetic diagnosis and appropriate family counseling. We report detailed clinical, electrophysiological, neuroimaging, histologic, biochemical and genetic characterization of 11 patients, from 6 consanguineous families, who were followed for a period of up to 17 years. Cerebellar atrophy was constant and the earliest feature of the disease preceding brain iron accumulation, leading to the provisional diagnosis of a recessive progressive ataxia in these patients. Ultrastructural characterization of patients' muscle biopsies revealed focal accumulation of granular and membranous material possibly resulting from defective membrane homeostasis caused by disrupted PLA2G6 function. Enzyme studies in one of these muscle biopsies provided evidence for a relatively low mitochondrial content, which is compatible with the structural mitochondrial alterations seen by electron microscopy. Genetic characterization of 11 patients led to the identification of six underlying PLA2G6 gene mutations, five of which are novel. Importantly, by combining clinical and genetic data we have observed that while the phenotype of neurodegeneration associated with PLA2G6 mutations is variable in this cohort of patients belonging to the same ethnic background, it is partially influenced by the genotype, considering the age at onset and the functional disability criteria. Molecular testing for PLA2G6 mutations is, therefore, indicated in childhood-onset ataxia syndromes, if neuroimaging shows cerebellar atrophy with or without evidence of iron accumulation.

Ophthalmologic observations in a patient with partial mosaic trisomy 8.

BACKGROUND: To carefully assess the phenotype and genotype of a patient with partial mosaic trisomy 8 with particular attention to ophthalmologic features. METHODS: Ophthalmologic and neuro-ophthalmologic examination; neuroimaging; conventional karyotyping; and array comparative genomic hybridization (CGH). RESULTS: The proband was the only affected child of a non-consanguineous family. At birth she was noted to have facial dysmorphism including telecanthus, low set ears, prominent nares, and an everted lower lip. She had an accommodative esotropia with otherwise normal globes, optic nerves, retinae, and orbits. She also had delayed motor milestones and mild mental retardation associated with agenesis of the corpus callosum. Both karyotyping and array CGH documented mosaic partial trisomy of chromosome 8 that included all of the "q" arm and part of the proximal "p" arm. CONCLUSIONS: This girl had a number of the classic features of mosaic trisomy 8, including an accommodative esotropia with none of the other ocular and orbital anomalies described in patients with mosaic trisomy 8. This report constitutes an initial effort to create a virtual database of patients with mosaic chromosome 8 in which careful phenotype-genotype correlation employing high resolution array CGH may help identify clues regarding the genetic etiology of ophthalmologic features of this syndrome.

Stroke in Saudi children. Epidemiology, clinical features and risk factors.

OBJECTIVES: To describe the epidemiology and clinical features of stroke in a prospective and retrospective cohort of Saudi children and ascertain the causes, pathogenesis, and risk factors. METHODS: The Retrospective Study Group (RSG) included children with stroke who were evaluated at the Division of Pediatric Neurology, or admitted to King Khalid University Hospital, College of Medicine, King Saud University, Riyadh, Kingdom of Saudi Arabia during the period July 1992 to February 2001. The Prospective Study Group (PSG) included those seen between February 2001 and March 2003. RESULTS: During the combined study periods of 10 years and 7 months, 117 children (61 males and 56 females, aged one month-12 years) were evaluated; the majority (89%) of these were Saudis. The calculated annual hospital frequency rate of stroke was 27.1/100,000 of the pediatric (1 month-12 years) population. The mean age at onset of the initial stroke in the 104 Saudi children was 27.1 months (SD = 39.3 months) and median was 6 months. Ischemic strokes accounted for the majority of cases (76%). Large-vessel infarcts (LVI, 51.9%) were more common than small-vessel lacunar lesions (SVLL, 19.2%). Five patients (4.8%) had combined LVI and SVLL. Intracranial hemorrhage was less common (18.2%), whereas sinovenous thrombosis was diagnosed in 6 (5.8%) patients. A major risk factor was identified in 94 of 104 (89.4%) Saudi children. Significantly more hematologic disorders and coagulopathies were identified in the PSG compared to the RSG (p=0.001), reflecting a better yield following introduction of more comprehensive hematologic and coagulation laboratory tests during the prospective study period. Hematologic disorders were the most common risk factor (46.2%), presumed perinatal ischemic cerebral injury was a risk factor in 23 children (22.1%) and infectious and inflammatory disorders of the circulatory system in 18 (17.3%). Congenital and genetic cerebrovascular anomalies were the underlying cause in 7 patients (6.7%) and cardiac diseases in 6 (5.8%). Six patients (5.8%) had moyamoya syndrome, which was associated with another disease in all of them. Inherited metabolic disorders (3.8%) included 3 children with Leigh syndrome and a 29-month-old girl with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. Systemic vascular disease was a risk factor in 3 children (2.9%) including 2 who had hypernatremic dehydration; and post-traumatic arterial dissection was causative in 3 cases (2.9%). Several patients had multiple risk factors, whereas no risk factor could be identified in 11 (10.6%). CONCLUSION: Due to the high prevalence and importance of multiple risk factors, a comprehensive investigation, including hematologic, neuroimaging and metabolic studies should be considered in every child with stroke.