Bilateral frontoparietal polymicrogyria.

Two male siblings, aged 4.5 and 10 y respectively, of a nonconsanguinous family, presented with delayed milestones and epilepsy. The older sibling had frequent seizures since 7 y of age. Seizures were generalized-tonic-clonic and were poorly controlled on valproate, phenytoin and clobazam. His younger sibling had seizures (myoclonic and generalized tonicclonic) since 2.5 y of age with partial response to valproate, levetiracetam and clobazam. The inter-ictal EEG showed multifocal epileptiform discharges in the older sibling and infrequent bilateral frontal spike-wave-discharges in the younger sibling. The examination of both the siblings revealed a normal head circumference, bilateral esotropia, pseudobulbar palsy andmild spasticity. Magnetic-Resonance-Imaging of the brain is shown as Fig. 1. One female sibling died (probable aspiration) at 3 y of age. She had global-developmental-delay and spasticity but no seizures. She was not investigated. There are three other female siblings who are alive and healthy. All coding exons 2–14 and exon/intron junctions in the gene GPR56 were sequenced. Both the siblings showed homozygous nucleotide mutation c.739_745 del (CAGGACC) leading to a protein variation p. Q247Cfs74. Both the parents were heterozygous for the same mutation. Polymicrogyria is a malformation-of-cortical-development characterized by excessive gyration and abnormal cortical structure and lamination. The various regional polymicrogyria syndromes reported include bilateral perisylvian polymicrogyria, bilateral frontal polymicrogyria, bilateral frontoparietal polymicrogyria (BFPP), bilateral parasagittal parietooccipital polymicrogyria and unilateral multilobar polymicrogyria [1]. BFPP is a recently described entity caused by mutations in G protein-coupled receptor 56 gene (GPR56). It has been rarely reported from India [2]. GPR56 gene may be critical for the preplate neurons, which are the earliest born neurons in the cortex with roles in cortical development and patterning [3]. Most patients present in infancy with severe hypotonia, ‘pseudomyopathic’ presentation and strabismus with normal serum creatine kinase levels. They later exhibit mental and motor retardation with pyramidal signs, epilepsy, language impairment, cerebellar signs and eye movement abnormalities. The neuroimaging shows bilateral polymicrogyria with P. Jain : S. Sharma : S. Aneja Division of Pediatric Neurology, Department of Pediatrics, Lady HardingeMedical College and Associated Kalawati Saran Children’s Hospital, New Delhi, India