Hemiconvulsion-hemiplegia-epilepsy syndrome with 1q44 microdeletion: causal or chance association.

Hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome is a rare syndrome characterized by childhood onset partial motor convulsions, hemiplegia, and epilepsy in sequence. Exact pathogenesis is not clear. Here we are describing a 3-year-old girl with HHE syndrome with cytogenetic microarray (CMA) showing deletion of 1.8 Mb in 1q44 region. Along with HHE syndrome, the patient also had global developmental delay, subtle facial dysmorphism, and preaxial polydactyly. Clinical phenotype of 1q44 microdeletion syndrome is quite variable. Main clinical features are microcephaly, seizures, and abnormality of corpus callosum. We compared the patient's phenotype with other patients in 10 previously published papers of 1q44 microdeletion syndrome. HNRNPU and FAM36A are two important genes in the deleted region. HNRNPU gene mediate long range control of SHH gene which is likely explanation of preaxial polydactyly in the present patient. HHE may be a chance co-occurrence.