Bi-allelic variants in HCRT cause autosomal recessive narcolepsy.

Narcolepsy with cataplexy is a complex disease with both genetic and environmental risk factors. To gain further insight into the homozygous HCRT-related narcolepsy, we present a case series of five patients from two consanguineous families, each harboring a novel homozygous variant of HCRT c.17_18del. All affected individuals exhibited severe cataplexy accompanied by narcolepsy symptoms during infancy. Additionally, cataplexy symptoms improved or disappeared in the majority of patients over time. Pathogenic variants in HCRT cause autosomal recessive narcolepsy with cataplexy. Genetic testing of the HCRT gene should be conducted in specific subgroups of narcolepsy, particularly those with early onset, familial cases, and a predominantly cataplexy phenotype.

Hereditary Hyperekplexia in Saudi Arabia.

BACKGROUND: Hyperekplexia is a rare disorder characterized by exaggerated startle responses to unexpected sensory stimuli, recurrent apneas, and stiffness. Only few studies have been published on this disorder in populations with high rates of consanguinity. METHODS: We retrospectively reviewed Saudi patients with genetically confirmed hereditary hyperekplexia using a standard questionnaire that was sent to nine major referral hospitals in Saudi Arabia. RESULTS: A total of 22 Saudi patients (11 males, 11 females) from 20 unrelated families who had hereditary hyperekplexia were included. Based on molecular studies, they were classified into different subtypes: SLC6A5 variant (12 patients, 54.5%), GLRB variant (seven patients, 31.8%), and GLRA1 variant (three patients, 13.7%). All patients were homozygous for the respective causal variant. The combined carrier frequency of hereditary hyperekplexia for the encountered founder mutations in the Saudi population is 10.9 per 10,000, which translates to a minimum disease burden of 13 patients per 1,000,000. CONCLUSION: Our study provides comprehensive epidemiologic information, prevalence figures, and clinical characteristics of a large cohort of patients with hereditary hyperekplexia.

Lisdexamfetamine Therapy in Paroxysmal Non-kinesigenic Dyskinesia Associated with the KCNMA1-N999S Variant.

BACKGROUND: KCNMA1-linked channelopathy is a rare movement disorder first reported in 2005. Paroxysmal non-kinesigenic dyskinesia (PNKD) in KCNMA1-linked channelopathy is the most common symptom in patients harboring the KCNMA1-N999S mutation. PNKD episodes occur up to hundreds of times daily with significant morbidity and limited treatment options, often in the context of epilepsy. CASES: We report 6 cases with the KCNMA1-N999S variant treated with lisdexamfetamine (0.7-1.25 mg/kg/day), a pro-drug of dextroamphetamine. Data were collected retrospectively from interviews and chart review. Parent-reported daily PNKD episode counts were reduced under treatment, ranging from a 10-fold decrease to complete resolution. CONCLUSION: Our findings suggest that lisdexamfetamine is an effective therapy for PNKD3 (KCNMA1-associated PNKD). Treatment produced dramatic reductions in debilitating dyskinesia episodes, without provocation or exacerbation of other KCNMA1-associated symptoms such as seizures.

Inherited Metabolic Causes of Stroke in Children: Mechanisms, Types, and Management.

A stroke should be considered in cases of neurologic decompensation associated with inherited metabolic disorders. A resultant stroke could be a classical ischemic stroke (vascular stroke) or more commonly a "metabolic stroke." A metabolic stroke begins with metabolic dysfunctions, usually caused by a stressor, and leads to the rapid onset of prolonged central neurological deficits in the absence of vessel occlusion or rupture. The cardinal features of a metabolic stroke are stroke-like episodes without the confirmation of ischemia in the typical vascular territories, such as that seen in classic thrombotic or embolic strokes. Identifying the underlying cause of a metabolic stroke is essential for prompt and appropriate treatment. This study reviews the major inherited metabolic disorders that predispose patients to pediatric stroke, with an emphasis on the underlying mechanisms, types, and management.

Spinal Cord Involvement in Pediatric-Onset Metabolic Disorders With Mendelian and Mitochondrial Inheritance.

Previous reviews have described the features of brain involvement in pediatric-onset metabolic disorders with Mendelian and mitochondrial inheritance, but only a few have focused on spinal cord abnormalities. An increasing number of metabolic disorders with Mendelian and mitochondrial inheritance in children with predominant spinal cord involvement has been recognized. Spinal cord involvement may be isolated or may occur more frequently with brain involvement. Timely diagnosis and occasional genetic counseling are needed for timely therapy. Therefore, clinicians must be aware of the clinical, laboratory, and radiographic features of these disorders. In this review, we describe pediatric-onset metabolic disorders with Mendelian and mitochondrial inheritance and predominant spinal cord involvement. Furthermore, we provide an overview of these conditions, including background information and examples that require rapid identification, focusing on treatable conditions; that would be catastrophic if they are not recognized.

Metabolic and genetic disorders mimicking cerebral palsy.

Cerebral palsy is a syndrome that encompasses a large group of childhood movement and posture disorders that result from a lesion occurring in the developing brain. The clinical presentation of many metabolic and genetic conditions, particularly in highly consanguineous populations, can mimic cerebral palsy particularly at early age. The aim of this review article is to identify the clinical features that should alert the physician to the possibility of disorders that resemble cerebral palsy, the clinical and neuroimaging red flags, and highlight some metabolic and genetic conditions which may present with spasticity, ataxia and dyskinesia. In the case of metabolic or genetic disorder, making a precise diagnosis is particularly important for the possibility of treatment, accurate prognosis and genetic counseling.

Penetrating Injury of the Heart From a Chronically Migrating Foreign Body.

A 46-year-old man experienced a remote unexpected lung injury with a sharp object. The object migrated over the years, penetrating the mediastinal structure, injuring the pericardium and the right-sided chambers of the heart. The injury was complicated by hemodynamic instability and pericardial tamponade. An emergent pericardiocentesis followed by thoracotomy, foreign body extraction, and puncture site closure. This is a very rare case of remote penetrating lung injury with a dormant course.

The incidence and spectrum of central nervous system malformations in newborns over a decade (2001-2010) in the Central Region of Saudi Arabia.

OBJECTIVE: To study the incidence and spectrum of central nervous system (CNS) malformations confirmed by computerized tomography (CT), or magnetic resonance imaging (MRI) in a Saudi newborn population of Riyadh over a 10-year period, and to compare our findings with those in the published literature. METHODS: This is a retrospective analysis of prospectively collected data on all inborn babies admitted to the Neonatal Intensive Care Unit in Riyadh Military Hospital, Riyadh, Kingdom of Saudi Arabia that underwent CT or MRI of the brain and spine from January 2001 to December 2010. Out born babies, babies who sustained birth asphyxia, and premature babies were excluded from the study. RESULTS: During the study period, 849 imaging studies were carried out, and from these 248 babies with CNS malformations were identified. Specific syndromes associated with CNS malformations occurred in 58 (23.4%). Dysraphism was found in 42 babies (16.9%) (25 spinal and 17 cranial). Hydrocephalus was present in 30 (12.1%), cortical malformations occurred in 31 (12.5%), which was dominated by abnormal cell migration in 20. Cerebellar and posterior fossa abnormalities were diagnosed in 44 (17.7%), Dandy-Walker syndrome in 15, and Joubert syndrome in 12. Prosencephalic pathology was seen in 39 (15.7%), commissural abnormalities in 29, while there was holoprosencephaly in 12. Vascular malformations were found in 4 babies (1.4%). CONCLUSION: This study showed a wide spectrum of malformations, with all CNS malformations confirmed by advanced imaging techniques.