Phenotypic Variability of Variants Causing Congenital Myopathy: Report of Two Unrelated Patients from a Highly Consanguineous Population.

Congenital myopathies are rare neuromuscular hereditary disorders that manifest at birth or during infancy and usually appear with muscle weakness and hypotonia. One of such disorders, early-onset myopathy, areflexia, respiratory distress, and dysphagia (EMARDD, OMIM: 614399, MIM: 612453), is a rare autosomal recessive disorder caused by biallelic mutations (at homozygous or compound heterozygous status) in (multiple epidermal growth factor-like domains protein family). Here, we report two unrelated patients, who were born to consanguineous parents, having two novel deleterious variants.

Biallelic and monoallelic variants in PLXNA1 are implicated in a novel neurodevelopmental disorder with variable cerebral and eye anomalies.

Purpose: To investigate the effect of PLXNA1 variants on the phenotype of patients with autosomal dominant and recessive inheritance patterns and to functionally characterize the zebrafish homologs plxna1a and plxna1b during development.

Methods: We assembled ten patients from seven families with biallelic or de novo PLXNA1 variants. We describe genotype-phenotype correlations, investigated the variants by structural modeling, and used Morpholino knockdown experiments in zebrafish to characterize the embryonic role of plxna1a and plxna1b.

Tuberous Sclerosis Complex: Clinical Spectrum and Epilepsy: A Retrospective Chart Review Study.

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic neurocutaneous disorder, with heterogeneous manifestations. We aimed to review the clinical presentation of TSC and its association with epilepsy among Saudi population. This was a retrospective chart review study of 88 patients diagnosed with TSC with or without epilepsy.

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.

Lethal digenic mutations in the K channels Kir4.1 () and SLACK () associated with severe-disabling seizures and neurodevelopmental delay.

A 2-yr-old boy presented profound developmental delay, failure to thrive, ataxia, hypotonia, and tonic-clonic seizures that caused the death of the patient. Targeted and whole exome sequencing revealed two heterozygous missense variants: a novel mutation in the gene that encodes for the inward-rectifying K channel Kir4.1 and another previously characterized mutation in that encodes for the Na-activated K channel known as Slo2.

The landscape of genetic diseases in Saudi Arabia based on the first 1000 diagnostic panels and exomes.

In this study, we report the experience of the only reference clinical next-generation sequencing lab in Saudi Arabia with the first 1000 families who span a wide-range of suspected Mendelian phenotypes. A total of 1019 tests were performed in the period of March 2016-December 2016 comprising 972 solo (index only), 14 duo (parents or affected siblings only), and 33 trio (index and parents). Multigene panels accounted for 672 tests, while whole exome sequencing (WES) represented the remaining 347 tests.

Acute disseminated encephalomyelitis and thrombocytopenia following Epstein-Barr virus infection.

Epstein-Barr Virus (EBV) causes a broad spectrum of disease in humans with several clinical syndromes and is ubiquitous, infecting more than 95% of the world's population. Central Nervous System (CNS) disease alone associated with Epstein-Barr virus rarely occurs in previously healthy individuals. Systemic viral illness in children and complications are rare, but may occur.

Paroxysmal autonomic instability with dystonia after pneumococcal meningoencephalitis.

Streptococcus pneumoniae is a common cause of bacterial meningitis, frequently resulting in severe neurological impairment. A seven-month-old child presenting with Streptococcus pneumoniae meningoencephalitis developed right basal ganglia and hypothalamic infarctions. Daily episodes of agitation, hypertension, tachycardia, diaphoresis, hyperthermia, and decerebrate posturing were observed.

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis in a young Lebanese girl.

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is a recently recognized autoimmune neurologic disorder that presents with severe neuropsychiatric symptoms in previously healthy children. A 4-year-old Lebanese girl presented with new-onset behavioral changes, orofacial dyskinesias, fluctuation in consciousness, inability to walk, and mutism. Antibodies directed against NMDA receptors were detected in the patient's serum and cerebrospinal fluid.

Cardiac involvement in nonketotic hyperglycinemia.

Nonketotic hyperglycinemia is an autosomal recessive disorder of glycine metabolism characterized by the accumulation of glycine in the serum and cerebrospinal fluid with elevated cerebrospinal fluid to serum glycine ratio. The disease primarily affects the central nervous system, and has not been previously associated with myocardial involvement. In this article, the authors report an infant with nonketotic hyperglycinemia, who was found to have progressive left ventricular hypertrophy and dysfunction.

Severe hypoglycemic seizures in a child receiving 6-mercaptopurine.

A 4-year-old boy with acute lymphoblastic leukemia who was receiving 6-mercaptopurine during the maintenance chemotherapy experienced prolonged generalized tonic nocturnal seizures because of severe hypoglycemia after his evening dose by a 12-hour period of fasting. Investigations ruled out all causes of these seizures other than the 6-mercaptopurine-induced severe hypoglycemia.

Severe cerebral vaso-occlusive disease in macrophage activation syndrome.

A 14-year-old girl was diagnosed with macrophage activation syndrome, based on clinical presentation, laboratory tests, and bone marrow aspirate findings. She developed severe central nervous system involvement in the form of seizure disorder and severe diffuse occlusive cerebral vasculopathy, with extensive collateral circulation consistent with moyamoya disease. To our knowledge, this description is the first of these findings in association with macrophage activation syndrome.