Genotype-phenotype correlation in IARS2-related diseases: A case report and review of literature.

Isoleucyl-tRNA synthetase 2 (IARS2) encodes mitochondrial isoleucine-tRNA synthetase. Pathogenic variants in the IARS2 gene are associated with mitochondrial disease. We report a female with IARS2 compound heterozygous variants, p.Val499Glyfs*14 and p.Arg784Trp who presented with infantile spasms, Leigh disease and Wolff-Parkinson White (WPW) pattern. This report expands the phenotypic spectrum of IARS2-related disease.

HSD10 disease in a female: A case report and review of literature.

HSD10 disease is a rare X-linked mitochondrial disorder caused by pathogenic variants in the HSD17B10 gene. The phenotype results from impaired 17ß-hydroxysteroid dehydrogenase 10 (17ß-HSD10) protein structure and function. HSD10 is a multifunctional protein involved in enzymatic degradation of isoleucine and branched-chain fatty acids, the metabolism of sex hormones and neurosteroids, as well as in regulating mitochondrial RNA maturation. HSD10 disease is characterised by progressive neurologic impairment. Disease onset is varied and includes neonatal-onset, infantile-onset and late-onset in males. Females can also be affected. Our index case is a 45-month-old female, who initially presented at 11 months of age with global developmental delay. She subsequently began to lose previously acquired cognitive and motor skills starting around 29 months of age. Brain MRI showed abnormalities in the basal ganglia indicative of possible mitochondrial disease. Urine organic acid analysis revealed elevations of 2-methyl-3-hydroxybutyric acid and tiglyglycine. HSD17B10 gene sequencing revealed a likely pathogenic variant, NM_001037811.2:c.439C>T (p.Arg147Cys) inherited from her mother, expected to be causative of HSD10 disease. Her X-chromosome inactivation study is consistent with a skewed X-inactivation pattern. We report a female patient with HSD10 disease caused by a missense pathogenic variant, Arg147Cys in the HSD17B10 gene. The patient is the fifth severely affected female with this disease. This case adds to the small number of known affected families with this highly variable disease in the literature. These findings support the possibility of X-inactivation patterns influencing the penetrance of HSD10 disease in females.

Treatment of Disorders of Tone and Other Considerations in Pediatric Movement Disorders.

Pediatric movement disorders (PMDs) consist of a heterogeneous group of signs and symptoms caused by numerous neurological diseases. Different neurological disorders in children also share overlapping movement disorders making a diagnosis of the underlying cause of the movement disorder challenging. The similarity of the symptoms across multiple disease types suggests that there may be a final common motor pathway causing the overlapping movement disorders. There are numerous disorders in children associated with disturbances in tone and involuntary movements. This chapter will focus primarily on those disorders that involve abnormalities of tone and other important considerations of pediatric movement disorders. This chapter will address rating scales and goals for treatment and will include a review of symptomatic treatment and, where possible, the treatment of the underlying disease processes. The chapter will review representative disorders, including an inborn error of metabolism, an autoimmune disorder, and a group of neurodegenerative disorders. These examples demonstrate how the disorder's underlying pathophysiology results in a specific approach to the underlying disease and the associated conditions of tone and involuntary movements. Finally, the multiple treatment options for cerebral palsy and considerations of cerebral palsy mimics will be discussed.

Diplopia With Dural Fibrotic Thickening.

Idiopathic hypertrophic pachymeningitis (HP) is a rare disorder of diffuse thickening of the cranial or spinal dura mater without an identifiable cause. Most common in adult males, idiopathic HP typically presents with headache with or without varied associated focal neurologic deficits and findings of dural enhancement on magnetic resonance imaging in a linear, nodular, or combined pattern. As it is felt to be an autoimmune disorder, treatment with high-dose corticosteroids is typically recommended, and without intervention, the course is usually progressive. The disease can commonly progress with a relapsing remitting course requiring other immune modulators such as methotrexate, azathioprine, or cyclophosphamide for control. Here, we describe a unique case of idiopathic HP as it presented in a pediatric patient and resolved without immunomodulatory therapy.

Genotype-phenotype correlation in interstitial 6q deletions: a report of 12 new cases.

Interstitial deletions of 6q are associated with variable phenotypes, including growth retardation, dysmorphic features, upper limb malformations, and Prader-Willi (PW)-like features. Only a minority of cases in the literature have been characterized with high resolution techniques, making genotype-phenotype correlations difficult. We report 12 individuals with overlapping, 200-kb to 16.4-Mb interstitial deletions within 6q15q22.33 characterized by microarray-based comparative genomic hybridization to better correlate deletion regions with specific phenotypes. Four individuals have a PW-like phenotype, though only two have deletion of SIM1, the candidate gene for this feature. Therefore, other genes on 6q may contribute to this phenotype including multiple genes on 6q16 and our newly proposed candidate, the transcription cofactor gene VGLL2 on 6q22.2. Two individuals present with movement disorders as a major feature, and ataxia is present in a third. The 4.1-Mb 6q22.1q22.2 critical region for movement disorders includes the cerebellar-expressed candidate gene GOPC. Observed brain malformations include thick corpus callosum in two subjects, cerebellar vermal hypoplasia in two subjects, and cerebellar atrophy in one subject. Seven subjects' deletions overlap a ~250-kb cluster of four genes on 6q22.1 including MARCKS, HDAC2, and HS3ST5, which are involved in neural development. Two subjects have only this gene cluster deleted, and one deletion was apparently de novo, suggesting at least one of these genes plays an important role in development. Although the phenotypes associated with 6q deletions can vary, using overlapping deletions to delineate critical regions improves genotype-phenotype correlation for interstitial 6q deletions.

Hypokalemia and alkalosis in adipsic hypernatremia are not associated with hyperaldosteronism.

Idiopathic adipsic hypernatremia (AH) is a rare disorder associated with hypokalemia and alkalosis. Hypokalemic alkalosis has been presumed to be secondary to hyperaldosteronism. We evaluated plasma renin activity, serum aldosterone, serum and urine electrolytes in a 17-year-old patient with AH on several occasions. Despite evidence of mild dehydration, serum Na >160 and K <3.2, aldosterone levels were suppressed and plasma renin activity was not elevated. Urine Na and K were not conserved. We also examined electrolyte and hormone levels in previously reported cases of AH. Aldosterone levels were not increased in any of the cases when measured. Renin secretion was increased in 2 patients. Among the compiled cases serum K was inversely correlated with serum Na (r = -0.73, p < 0.002, n = 15). Hypokalemia and alkalosis occurring in AH are not associated with secondary hyperaldosteronism. Patients with AH may have chronic renal losses of potassium leading to hypokalemia and alkalosis.

Sudden blindness in a child with end-stage renal disease.

Continuous peritoneal dialysis (CPD) is the preferred modality for renal replacement therapy in children with end-stage renal disease. Anterior ischemic optic neuropathy (AION) is a rare complication in patients on CPD. AION is characterized by ischemic injury of the optic nerve caused by hypoperfusion of the posterior ciliary arteries. It presents with acute visual loss and disc swelling, without additional neurological findings. We report a 2-year-old child with end-stage renal disease on CPD who developed AION. He was dehydrated and received intravenous fluid on admission. Additional treatment included methylprednisolone and levodopa. On his 3rd admission day, his pupils became reactive to light and his vision showed improvement. The improvement in vision might be due to the early detection and aggressive treatment of hypotension. It is difficult to demonstrate whether steroids or levodopa played a role in the improvement of his vision. Prospective studies to evaluate the effectiveness of levodopa in the treatment of AION are warranted in this potentially devastating condition.

Shaking-impact syndrome of infancy.

Shaking-impact syndrome (SIS) is a leading cause of traumatic brain injury in infants and young children. Evaluation of these children requires a detailed history and physical examination as well as documentation of intracranial injury with neuroimaging, a dilated fundoscopic examination, a skeletal survey and other laboratory studies. Debate still exists as to the exact mechanisms of brain injury in these patients. The various contributions of shaking alone, shaking with impact, and apnea are discussed. Differences of injury type and severity between accidental traumatic brain injury and SIS are delineated. The long-term neurodevelopmental outcome for survivors of SIS is generally poor. Because few treatment options are successful in reducing the morbidity and mortality of this syndrome, prevention may be the only reasonable solution.