Imaging of the craniovertebral junction anomalies in children

Cryptogenic posterior circulation stroke in children

We aimed to evaluate the percentage of posterior circulation arterial ischaemic stroke (PCAIS) caused by craniovertebral junction (CVJ) anomalies and describe their clinical course. Children admitted to a tertiary care paediatric hospital with PCAIS between July 2017 and December 2020 were assessed retrospectively for disease aetiology. We reviewed the clinical, radiological, and surgical details of children with evidence of CVJ anomalies. Fourteen (24.1%) of 58 children admitted with arterial ischaemic stroke had posterior circulation involvement. The mean age of patients presenting with posterior circulation stroke was 6 years 6 months (range 3 months-15 years), 11 were male. Six of 14 cases with PCAIS were due to CVJ anomaly, their ages ranged from 4 months to 15 years (two age ranges were noted, 4 months-4 years and 11-15 years), four were male. Two children had atlantoaxial dislocation with basilar invagination, two had Bow Hunter syndrome with Chiari malformation type 1 (one with completed stroke), one had Chiari malformation type 1 alone, and one presented with Farber disease with proatlas segmentation anomaly in CVJ. The time lag to stroke and CVJ diagnosis ranged from 2 weeks to 24 months. A dynamic angiogram was required to evaluate biomechanical changes on scans with inconclusive findings on standard stroke imaging. CVJ anomalies are an important treatable cause of paediatric posterior circulation stroke. Cervical spine x-ray in flexion and extension should be done in all patients with posterior circulation stroke beyond the acute period. In cryptogenic aetiology, provocative angiography with guarded neck rotation should be considered to evaluate possible dynamic vertebral artery compression.

Expanding the phenotype of Wiedemann-Steiner syndrome: Craniovertebral junction anomalies

Wiedemann-Steiner syndrome (WDSTS) is a rare autosomal dominant condition caused by heterozygous loss of function variants in the KMT2A (MLL) gene, encoding a lysine N-methyltransferase that mediates a histone methylation pattern specific for epigenetic transcriptional activation. WDSTS is characterized by a distinctive facial phenotype, hypertrichosis, short stature, developmental delay, intellectual disability, congenital malformations, and skeletal anomalies. Recently, a few patients have been reported having abnormal skeletal development of the cervical spine. Here we describe 11 such individuals, all with KMT2A de novo loss-of-function variants: 10 showed craniovertebral junction anomalies, while an 11th patient had a cervical abnormality in C7. By evaluating clinical and diagnostic imaging data we characterized these anomalies, which consist primarily of fused cervical vertebrae, C1 and C2 abnormalities, small foramen magnum and Chiari malformation type I. Craniovertebral anomalies in WDSTS patients have been largely disregarded so far, but the increasing number of reports suggests that they may be an intrinsic feature of this syndrome. Specific investigation strategies should be considered for early identification and prevention of craniovertebral junction complications in WDSTS patients.