Sinus pericranii and myoclonic epilepsy: novel features of 3q29 microdeletion syndrome.

The 3q29 microdeletion syndrome, a newly recognizable genetic disorder, has less than 50 reported cases in the literature. Clinical features consist of learning disability, autistic symptoms, psychiatric disorders and ocular abnormalities [1]. We report 2 novel features of this genetic syndrome. An 8-month-old boy was presented to the hospital with complaints of episodes of shoulder jerking. He was born at 38 weeks of gestation in a 2nd gravida mother. Antenatal history was significant for polyhydramnios. During delivery, amniotic fluid was meconium stained and due to an 1-min poor Apgar score, he received oxygen—administered with face mask for few minutes. A small area of softness was noted over the scalp behind anterior fontanel during neonatal period, but no intervention was done. Past medical history was significant for surgical management for penile torsion and chordae. Developmental delay was noted in first few months of his life. At presentation, his weight, length and head circumference were 10th, 20th, and 50th percentile, respectively. Mild facial dysmorphism with high nasal bridge, mild facial asymmetry, and pectus excavatum was seen. He had good head control but was not able to roll over from back to front or sit unsupported. He could coo but did not have ability to babble. He tried to grab objects with immature grip but could not transfer objects from one hand to other. Cranial nerve examination was normal except horizontal nystagmus was occasionally seen. Muscle tone was normal with symmetric movement of extremities. Reflexes and sensory examination did not reveal any abnormality. The soft tissue mass (2 9 2 cm) was very soft in palpation and was present posterior to the anterior fontanel. His anterior fontanel was also noted to be somewhat wide, approximately 3 9 3 cm, but soft in palpation. Other organ examination was unremarkable. Video electroencephalography captured several episodes of single myoclonic and sequential myoclonic jerks in a row with high-amplitude generalized spike wave discharge lasting for 1–2 s. MRI brain revealed sinus pericranii and persistent parafalcine sinus (Fig. 1). No abnormality of brain parenchyma or myelination pattern was evident. Chromosomal microarray and Fragile X DNA testing was performed for developmental delay. The cytogenomic array analysis detected a 1.7 Mb deletion in chromosome 3 within q29 (arr[hg19] 3q29(195,703,615197,356,334) region. Follow-up over the next 1 year revealed that he slowly acquired developmental milestones. At 2 years, he was walking, running and had vocabulary of 20 words. He showed intermittent aggressive behaviors, mostly situation dependent. His myoclonic seizures were well controlled with levetiracetam. Sinus pericranii was obliterated by ligation at the age of 17 months due to complaints of local tenderness with no complication. Several distinct epilepsy syndromes with myoclonic seizures are seen in infancy and early childhood such as benign myoclonic epilepsy in infancy (BMEI), Dravet syndrome and Doose syndrome. This patient’s clinical feature most closely follows BMEI rather than the other two types. Easily controlled myoclonic jerks with antiepileptic drugs, absence of developmental regression, and normal interictal EEG seen in our patient are similar to features seen in BMEI. There are total 13 known genes present in the deleted portion of the microdeletion syndrome in our patient and no particular association with & Debopam Samanta dsamanta@uams.edu