Cognitive and Behavioral Profile in a Child with Macrocerebellum - A Rare Congenital Brain Malformation

Macrocerebellum is a rare condition marked by an aberrant growth in the size of the cerebellum without any morphological or signal abnormalities. It can occur in isolation (nonsyndromic) or as part of various clinical syndromes such as Costello's syndrome, Sotos syndrome, Williams' syndrome, macrocephaly-capillary malformation syndrome, mucopolysaccharidosis, and Lhermitte–Duclos' syndrome. The most common clinical features described with macrocerebellum are developmental delay, hypotonia, ataxia, nystagmus, oculomotor apraxia, seizures, and facial dysmorphism. The exact pathophysiological basis underneath this condition is still unknown. We report the case of a 13-month-old boy who presented with developmental delay, nystagmus, and generalized hypotonia. The presence of nystagmus made us suspect cerebellar pathology in this child. Magnetic resonance imaging of brain showed macrocerebellum which was confirmed by volumetric analysis. He did not have any clinical features to suggest a syndrome associated with macrocerebellum. His developmental quotient was 45, and his receptive and expressive language age was around 5 to 6 months. His genetic analysis by whole exome sequencing did not reveal any disease-causing variants. A repeat clinical evaluation after 4 months showed an improvement in motor domains.