P43 – 2841: Development coordination disorder (DCD) and attention deficit hyperactivity disorder (ADHD) as the initial presentation of bilateral fronto-parietal polymicrogyria type 2 (BFPP2) secondary to GPR56 mutation

Abstract

Introduction Bilateral Fronto-Parietal Polymicrogyria type 1 (BFPP1; OMIM 606854) is an autosomic recessive affection usually linked to GPR56. Clinical (mental retardation, cerebellar signs, severe psychomotor delay and symptomatic generalized epilepsy) and radiological (bilateral fronto-parietal polymicrogyria with an anterior to posterior gradient with brainstem and cerebellar hypoplasia) signs are specific. Patients with BFPP without cerebellar or brainstem abnormalities (BFPP2) have a milder phenotype and are not linked to GPR56 mutation (Piao et al., 2005; Bahi-Buisson et al., 2010). We report here a patient with specific learning disorder (Development Coordination Disorder-DCD and attention deficit hyperactivity disorder-ADHD) that presented the radiological characteristics of BFPP2 and harbor a GPR56 mutation. Case report 4-year-old boy with a normal psychomotor and speech development, presenting awkwardness, learning difficulties and ADHD. Familial and personal history was unremarkable. Neurological examination was normal. Neuropsychological tests performed at 5.5 years showed DCD (Mouvement assessment Battery for Children-M-ABC scale –2SD and WPPSI-III: ICV=100, IRP=71, IVT=71 with severe dysgraphia) and ADHD. EEG was normal. He received a multidisciplinary rehabilitation and methylphenidate with an improvement of his learning disabilities even though he needed special school when he left kindergarten. When he was 7, he presented shock-like episodes with absences. Prolonged video-EEG showed 2Hz generalized spikes and waves, atypical absences and tonic seizures. Brain MRI revealed BFPP2. DNA analysis revealed compound heterozygoty in GPR56, parents where heterozygous for GPR56. Conclusion This case is, to our knowledge, the first case of BFPP2 phenotype presenting initially as a specific learning disorder and harbouring compound heterozigoty in GPR56.