Clinical Reasoning: A girl presenting with stiffness episodes during sleep, café-au-lait spots, and flecked retina

A 4-year-old girl who had been born of normal pregnancy and delivery and had an unremarkable family or personal history was referred to a neuropsychiatric department because of the appearance of peculiar nocturnal episodes. Parents described that their child abruptly became stiff during sleep. These episodes usually ranged from 20 to 40 seconds, and after that the child continued to sleep. Initially she presented 1 episode per week, but there was a progressive increase in frequency up to 3 to 4 times per night. The child never presented similar episodes while awake. Her examination revealed some café-au-lait spots, congenital microcephaly (3rd centile) and low stature for the age (10th centile). She did not present any neurologic deficit, but she failed to develop an age-appropriate speech, with a delay in the main language milestones.