Hemiplegic migraine--downstream of a single-base change

Identification of a novel CACNA1A mutation in a Chinese family with autosomal recessive progressive myoclonic epilepsy

BACKGROUND

Progressive myoclonic epilepsy (PME) is a heterogeneous neurodegenerative disorder, which is commonly manifested with refractory seizures and neurologic deterioration. The prognosis of PME is poor, so early diagnosis of PME is critical. The aim of our study is to identify the novel pathogenic gene in a Chinese family with PME, which may be helpful in future.

SUBJECTS AND METHODS

A three-generation consanguineous Chinese Han family with PME was recruited. A novel homozygous variant was identified by the genetic technique of exome sequencing and certificated by Sanger sequencing and functional prediction.

RESULTS

A novel homozygous variant, c.6975_6976insCAG, in the CACNA1A was identified in the PME family. The novel variant encoding the alpha-1A subunit of the calcium channel Cav2.1 was found in two siblings in the Chinese family and was absent in 50 normal controls. Our research indicates that the homozygous c.6975_6976insCAG might be the pathogenic mutation for PME.

CONCLUSION

As a molecular diagnostic strategy, our research explores the mutation gene spectrum of PME and has resulted in significant predictions for genetic counseling.

Congenital ataxia, mental retardation, and dyskinesia associated with a novel CACNA1A mutation

The CACNA1A gene encodes the pore forming alpha-1A subunit of neuronal voltage-dependent P/Q-type Ca( 2+) channels. Mutations in this gene result in clinical heterogeneity, and present with either chronic progressive symptoms, paroxysmal events, or both, with clinical overlap among the different phenotypes. The authors describe a seven year-old boy with mental retardation and congenital cerebellar ataxia that developed dyskinesia at the age of a few months, and recurrent episodes of coma following mild head trauma associated with motor and autonomic signs, from the second year of life. An extensive metabolic evaluation, interictal electroencephalography (EEG), and muscle biopsy were normal. Brain magnetic resonance imaging (MRI) during one of these episodes revealed edema of the right hemisphere and cerebellar atrophy. Genetic testing revealed a R1350Q mutation in the CACNA1A gene. This is a novel de novo mutation.Congenital cerebellar ataxia can be a result of CACNA1A mutations, especially when associated with recurrent unexplained coma.

Acute hemiparesis in a boy with type 1 diabetes

Unlike the case in adult-onset diabetes, neurologic complications in children with type 1 diabetes are uncommon. We report a case of a 14-year-old boy with type 1 diabetes who presented at our emergency unit with acute hemiparesis and intense headache without hypoglycaemia. Two hours after onset, the symptoms had subsided. It is the intention of the authors to increase the awareness of this association, whose prognosis is almost invariably good.