Static Leukoencephalopathy Associated with 17p13.3 Microdeletion Syndrome: A Case Report.

BACKGROUND: Leukoencephalopathy associated with dysmorphic features may be attributed to chromosomal abnormalities such as 17p13.3 microdeletion syndrome. CASE: A 19-year-old female patient was referred to our hospital for diagnostic evaluation of her leukoencephalopathy. She demonstrated moderate intellectual disability, minor dysmorphic features, and short stature. Serial brain magnetic resonance images obtained within a 16-year interval revealed prolonged T2 signals in the deep cerebral white matter with enlarged Virchow-Robin spaces. A nonsymptomatic atlas anomaly was also noted. Using microarray-based comparative genomic hybridization, we identified a 2.2-Mb terminal deletion at 17p13.3, encompassing YWHAE, CRK, and RTN4RL1 but not PAFAH1B1. CONCLUSION: Except for atlas anomaly, the patient's clinical and imaging findings were compatible with the diagnosis of 17p13.3 microdeletion syndrome. The white matter abnormality was static and nonprogressive. The association between the atlas abnormality and this deletion remains elusive. We note the importance of exploring submicroscopic chromosomal imbalance when patients show prominent but static white matter abnormalities with discrepantly mild and stable neurological signs.

Hyperglycemic Crisis in Patients With Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like Episodes (MELAS).

BACKGROUND: Diabetes mellitus is the most commonly encountered endocrinopathy in patients with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), which manifests as multisystemic organ failure. Whether the management of diabetes mellitus in MELAS requires special consideration is not fully clarified. METHODS: In this single-center study, we retrospectively reviewed the medical records of patients with MELAS to elucidate the clinical characteristics of MELAS-associated diabetes mellitus. RESULTS: Four patients among a total of 25 individuals with MELAS who were treated in the study institution developed diabetes mellitus. One patient had well-controlled diabetes mellitus, whereas the remaining three patients experienced hyperglycemic crisis as the first manifestation of diabetes mellitus. Two of the three patients were children aged four and six years. The hyperglycemic events occurred after surgery, infection, and status epilepticus, respectively. None of the three patients had diabetes mellitus previously based on randomly measured serum glucose levels that were within the normal range before the hyperglycemic crisis. Glycated hemoglobin levels measured during the hyperglycemic crisis indicated prediabetes in two patients and diabetes mellitus in one patient. Two patients recovered, whereas one patient died after developing multiorgan failure. CONCLUSIONS: Fulminant-onset diabetes mellitus occurring in patients with MELAS underscore the importance of routine measurement for glycated hemoglobin and more intense evaluation of glucose intolerance regardless of the patient age and lack of symptoms. Clinicians should be aware of the potential acute onset of hyperglycemic crisis in patients with MELAS, especially in individuals with aggravating factors.

KCNT1-positive epilepsy of infancy with migrating focal seizures successfully treated with nonnarcotic antitussive drugs after treatment failure with quinidine: A case report.

BACKGROUND: Epilepsy of infancy with migrating focal seizures (EIMFS) is one of the early-onset epileptic encephalopathies resistant to antiepileptic drugs, therefore carrying an extremely poor neurodevelopmental outcome. KCNT1, encoding for a sodium-activated potassium channel (KCa4.1 channel), has recently been reported as the major gene responsible for EIMFS. Since gain of function is the only type of mutation identified in patients with EIMFS, quinidine, a partial antagonist of KCa4.1 channel, is considered as a potential candidate for targeted treatment of EIMFS. However, treatment results reported so far vary from seizure-free state to no response, and cardiac side effect remains a challenge for dose titration and long-term treatment. CASE REPORT: Our case was an infant diagnosed with EIMFS with confirmed mutation in KCNT1 gene. Quinidine therapy was started as early as 9 months old. Within the first month of treatment, the number of seizures reduced to about one third. However, seizure-free state was not obtained and his neuropsychological development remained severely delayed. After 16 months of treatment, quinidine had to be discontinued because of cardiac side effects. At 27 months of age, however, his seizures suddenly stopped and he remained seizure-free for five days. This coincided with the prescription of tipepidine, a commonly used antitussive, administered for his persistent cough. Reduction in seizure frequency was also observed with dextromethorphan, another conventional antitussive drug. Although the relation between these treatments and his symptom improvement is a matter of elucidation, there is a possibility that these nonnarcotic antitussive drugs might play a role in the treatment of EIFMS.

Single-fiber electromyography-based diagnosis of CACNA1A mutation in children: A potential role of the electrodiagnosis in the era of whole exome sequencing.

INTRODUCTION: A loss-of-function mutation in CACNA1A, which encodes P/Q-type Ca channels, causes various diseases. As most of the Ca channels at neuromuscular junctions are of the P/Q type, patients with loss-of-function CACNA1A mutations exhibit disturbed neuromuscular transmission. The associated jitters and blocking in such patients can be detected by single-fiber electromyography (SFEMG). CASES: We report two cases with different phenotypes, which were predicted to harbor loss-of-function mutations of CACNA1A, by using axonal stimulation SFEMG. One case involved a 2-year-old boy with episodic ataxia type 2. The other case involved a 7-year-old girl diagnosed with epileptic encephalopathy. SFEMG results revealed jitters and blocking in both cases. Moreover, whole exome sequencing (WES) revealed a heterozygous CACNA1A mutation, c.5251C>T, p.Arg1751Trp, in the former case and a novel de novo CACNA1A mutation, c.2122G>A, p.Val708Met, in the latter. CONCLUSIONS: Our cases indicate that SFEMG is a potentially useful diagnostic tool for patients with CACNA1A mutation, especially in pediatric cases where trio analysis is difficult or novel mutations are present.