Arteriovenous Cerebral High Flow Shunts in Children: From Genotype to Phenotype.

Objective: To study the genotypes and phenotypes of cerebral arteriovenous fistulas that drain or do not drain through the vein of Galen, and true vein of Galen aneurysmal malformations, in order to determine whether genotyping could help improve classification of these malformations and their management. Methods: We carried out a retrospective review of genetic and phenotypic data in databases of four centers. All children with cerebral arteriovenous fistula or vein of Galen aneurysmal malformations aged below 18 years at onset were included. We recorded the nature of the genetic variant or absence of variant, age at onset, type of malformation, symptoms at onset (hemorrhage, neurological deficit, hydrocephalus, incidental, and heart failure), type of venous drainage and the long-term outcome. Results: One hundred and fifteen children were included. Autosomal dominant variants were identified in 39% of patients. The most frequent variant affected was the RASA1 gene (25%) followed by EPHB4 (8%) and the HHT-associated genes (5%). HHT gene variants were only observed in pial arteriovenous fistula not draining into the vein of Galen; on the contrary, EPHB4 variants were only seen in genuine vein of Galen aneurysmal malformation. RASA1 variants were identified in all types of shunts. Conclusions: EPHB4 variants seem specific to the vein of Galen aneurysmal malformation, RASA1 variants are associated with either pial arteriovenous fistulas or with genuine VGAM and HHT gene variants seem specific to pial arteriovenous fistulas. The genetic data helps to classify these malformations and to guide treatment toward lowest risk of post-operative cerebral ischemic-hemorrhagic complications.

Unilateral and segmental distribution of facial erythema: is it a real port-wine stain?

Capillary malformation-arteriovenous malformations (CM-AVMs) caused by a RASA-1 or EPHB4 mutation are characterized as hereditary sporadic or multifocal capillary malformations (CMs), associated with potential fast-flow vascular anomalies underlying erythema lesions. Because of the similar phenotype, CM-AVMs should be considered in the differential diagnosis of isolated CMs as well as other disorders with an erythema phenotype, such as hereditary hemorrhagic telangiectasia (HHT).Herein, we report a male patient with facial erythema. Red lesions were located in the V1 region of his left face, the V2 and V3 regions on his right side, and the nasal back. The patient was initially thought to have PWSs because of the unilateral and segmental distribution of his red facial lesions. In contrast to a previous diagnosis, we diagnosed the child with capillary malformation-arteriovenous malformation type 2 (CM-AVM2) based on a family history of erythema, the results of physical examination and ultrasound raising potential fast-flow lesions, and a genetic study revealing a germline EPHB4 mutation. This study emphasizes the importance of differential diagnosis for PWS and CM-AVM. A single clinical diagnosis can be limited, and molecular diagnosis is recommended to provide more information for the evaluation of the potential risk of fast-flow lesions underlying erythema lesions if necessary.