Early behavioural manifestation of Smith-Magenis syndrome (del 17p11.2) in a 4-month-old boy

Abstract

Objective: There is little systematic data on early neurodevelopmental functioning of infants with Smith-Magenis syndrome, since early diagnosis is rare. Methods: A boy with cytogenetically confirmed Smith-Magenis syndrome was videotaped at 4 months and 1 week of age. His posture and spontaneous movements were analysed without knowing the diagnosis. Results: The motor repertoire appeared significantly reduced; fidgety general movements, which are typical of that age, were missing. Posture was abnormal and overall movements were jerky and monotonous. The findings indicate a severe motor impairment by no more than 4 months of age. Conclusion: It was concluded that an absence of fidgety movements that goes along with subtle dysmorphic features indicates an increased risk of maldevelopment and justifies the need to refer for genetic evaluation with the potential of facilitating earlier diagnosis.