Congenital Hypothyroidism with Neuronal Migration Anomaly

A 12-year-old female with a previously known case of congenital hypothyroidism presented to our hospital with one episode of up-rolling of eyes and loss of consciousness 1 month back. She has been a known case of hypothyroidism since birth and is presently on thyroid hormone supplementation (thyroxine 25 mcg once daily) with laboratory parameters of T3 = 2.69, T4 = 1.14, and TSH = 1.85. Magnetic resonance imaging (MRI) of brain demonstrated a 10 × 8mm nodule in the subependymal margin of the left lateral ventricle, suggesting subependymal nodular heterotopia [Figure 1a-f].Figure 1: Magnetic resonance imaging showed periventricular nodular heterotopia. MR axial T2 (a), FLAIR (b), and T1 (c) images showed a subependymal nodule (white arrows), similar in signal intensity to gray matter along frontal horn of left lateral ventricle. DWI (d) and ADC (e) images showed no restricted diffusion (white arrows), and SWI (f) image showed no blooming (white arrow)Between the third and fifth months of gestation, normal neuronal migration takes place. Neurons migrate from the germinal matrix toward the brain's pial surface. The thyroid hormone (triiodothyronine) plays a vital role in brain development, and it regulates glial myelination, neuronal proliferation, neuronal migration, formation of cortical layers, and synapse formation.[1] Hence, congenital hypothyroidism can cause abnormal neuronal migration, synaptogenesis, and impairment of myelination. Gray matter heterotopia is defined as abnormal disorganized neurons at abnormal locations, anywhere between the subependymal region and the cortex, due to pre-mature arrest of neuronal migration. Subependymal heterotopia is described as gray matter nodules lining the lateral ventricular walls, most commonly in the trigone and occipital horn of the lateral ventricle.[2] It presents as epilepsy, intellectual disability, or developmental delay.[3] On MR imaging, these nodules show similar signal intensity in all MRI sequences and no enhancement in postcontrast study. Disclosure "The authors hereby certify that the work shown here is genuine, original and not submitted anywhere, either in part or full. They transfer the full rights of the video to Neurology India. All the necessary permissions from the patient, hospital and institution have been taken for submitting this video to Neurology India". Patient's consent "A full and detailed consent from the patient/guardian has been taken. The patient's identity has been adequately anonymized. If anything related to the patient's identity is shown, adequate consent has been taken from the patient/relative/guardian. The journal will not be responsible for any medico-legal issues arising out of issues related to patient's identity or any other issues arising from the public display of the video". Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.