ObjectiveTo determine the cause and course of a novel syndrome with progressive encephalopathy and brain atrophy in children.MethodsClinical whole-exome sequencing was performed for global developmental delay and intellectual disability; some patients also had spastic paraparesis and evidence of clinical regression. Six patients were identified with de novo missense mutations in the kinesin gene KIF1A. The predicted functional disruption of these mutations was assessed in silico to compare the calculated conformational flexibility and estimated efficiency of ATP binding to kinesin motor domains of wild-type (WT) versus mutant alleles. Additionally, an in vitro microtubule gliding assay was performed to assess the effects of de novo dominant, inherited recessive, and polymorphic variants on KIF1A motor function.ResultsAll six subjects had severe developmental delay, hypotonia, and varying degrees of hyperreflexia and spastic paraparesis. Microcephaly, cortical visual impairment, optic neuropathy, peripheral neuropathy, ataxia, epilepsy, and movement disorders were also observed. All six patients had a degenerative neurologic course with progressive cerebral and cerebellar atrophy seen on sequential magnetic resonance imaging scans. Computational modeling of mutant protein structures when compared to WT kinesin showed substantial differences in conformational flexibility and ATP-binding efficiency. The de novo KIF1A mutants were nonmotile in the microtubule gliding assay.InterpretationDe novo mutations in KIF1A cause a degenerative neurologic syndrome with brain atrophy. Computational and in vitro assays differentiate the severity of dominant de novo heterozygous versus inherited recessive KIF1A mutations. The profound effect de novo mutations have on axonal transport is likely related to the cause of progressive neurologic impairment in these patients.

Routine removal of nonspinal, orthopedic implants from pediatric patients is a debated practice. The purpose of this study was to compare preremoval and postremoval outcome measures in children. Twenty-five patients, mean age 11.6 years, completed a pain scale and the Pediatric Outcomes Data Collection Instrument (PODCI). Many patients scored in the normal range of the PODCI before and after removal. Higher postoperative PODCI scores were found in patients without preoperative pain, and in patients with upper extremity versus lower extremity implants. In summary, routine removal of implants in children was carried out without complications and with some functional benefits.

Although traditional hallucinogenic drugs such as marijuana and lysergic acid diethylamide (LSD) are not typically associated with seizures, newer synthetic hallucinogenic drugs can provoke seizures. Here, we report the unexpected consequences of taking a street-bought hallucinogenic drug thought to be LSD. Our patient presented with hallucinations and agitation progressing to status epilepticus with a urine toxicology screen positive only for cannabinoids and opioids. Using liquid chromatography high-resolution mass spectrometry, an additional drug was found: an amphetamine-derived phenylethylamine called 2,5-dimethoxy-4-chloroamphetamine. We bring this to the attention of the neurologic community as there are a growing number of hallucinogenic street drugs that are negative on standard urine toxicology and cause effects that are unexpected for both the patient and the neurologist, including seizures.

No abstract