Static encephalopathy of childhood with neurodegeneration in adulthood (SENDA) is a recently established subtype of neurodegeneration with brain iron accumulation (NBIA). By exome sequencing, we found de novo heterozygous mutations in WDR45 at Xp11.23 in two individuals with SENDA, and three additional WDR45 mutations were identified in three other subjects by Sanger sequencing. Using lymphoblastoid cell lines (LCLs) derived from the subjects, aberrant splicing was confirmed in two, and protein expression was observed to be severely impaired in all five. WDR45 encodes WD-repeat domain 45 (WDR45). WDR45 (also known as WIPI4) is one of the four mammalian homologs of yeast Atg18, which has an important role in autophagy. Lower autophagic activity and accumulation of aberrant early autophagic structures were demonstrated in the LCLs of the affected subjects. These findings provide direct evidence that an autophagy defect is indeed associated with a neurodegenerative disorder in humans.
Of 71 acute lymphoblastic leukemia survivors at our hospital over the past 10 years, 2 children developed mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). This is the first report to describe the clinical course of MTLE-HS observed longitudinally by EEG and MRI. Patient 1 experienced a seizure during chemotherapy involving intrathecal methotrexate. Postseizure MRI suggested methotrexate encephalopathy or leukemic invasion. Anticonvulsant therapy was initiated; subsequent EEGs and MRIs revealed normal results. Three years after chemotherapy, a diffuse, irregular spike-and-wave pattern was observed on interictal EEG. Five years after chemotherapy, the patient developed MTLE-HS comprising complex partial seizures, typical temporal spikes on EEG, and hippocampal sclerosis (HS). Patient 2 did not experience seizures during chemotherapy. Four years later, the patient started experiencing complex partial seizures, and a diffuse, irregular spike-and-wave pattern was observed on interictal EEG. A clinical picture of MTLE-HS developed 2 years later. In both patients, nonspecific EEG abnormalities (ie, diffuse, irregular spike-and-wave activity) preceded the appearance of HS on MRI by 2 years, suggesting an insidious advance of HS during the latent period. Such atypical EEG findings may indicate MTLE-HS during follow-up of leukemia patients. MTLE-HS develops several years after an initial precipitating incident such as prolonged seizures, central nervous system infection, and brain trauma. In our cases, the initial precipitating incident may have been chemotherapy and/or prolonged seizures. Thus, MTLE-HS associated with leukemia may not be as rare as generally believed. A large cohort study of late neurologic complications is warranted. Pediatrics 2013;132:e252-e256
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