Biallelic ADAM22 pathogenic variants cause progressive encephalopathy and infantile-onset refractory epilepsy.

Pathogenic variants in A Disintegrin And Metalloproteinase (ADAM) 22, the postsynaptic cell membrane receptor for the glycoprotein leucine-rich repeat glioma-inactivated protein 1 (LGI1), have been recently associated with recessive developmental and epileptic encephalopathy. However, so far, only two affected individuals have been described and many features of this disorder are unknown. We refine the phenotype and report 19 additional individuals harbouring compound heterozygous or homozygous inactivating ADAM22 variants, of whom 18 had clinical data available. Additionally, we provide follow-up data from two previously reported cases. All affected individuals exhibited infantile-onset, treatment-resistant epilepsy. Additional clinical features included moderate to profound global developmental delay/intellectual disability (20/20), hypotonia (12/20) and delayed motor development (19/20). Brain MRI findings included cerebral atrophy (13/20), supported by post-mortem histological examination in patient-derived brain tissue, cerebellar vermis atrophy (5/20), and callosal hypoplasia (4/20). Functional studies in transfected cell lines confirmed the deleteriousness of all identified variants and indicated at least three distinct pathological mechanisms: (i) defective cell membrane expression; (ii) impaired LGI1-binding; and/or (iii) impaired interaction with the postsynaptic density protein PSD-95. We reveal novel clinical and molecular hallmarks of ADAM22 deficiency and provide knowledge that might inform clinical management and early diagnostics.

Prospective study of continuous infusion with Beriate® P in patients with severe haemophilia A undergoing surgery - a subgroup analysis.

INTRODUCTION: Inhibitor development in severe haemophilia A patients is currently the most serious complication of factor VIII (FVIII) treatment. Although continuous infusion (CI) of FVIII concentrate during surgical procedures in haemophilia A patients has been shown to be beneficial, some publications suggest that CI increases the risk of inhibitor generation. We conducted a prospective subgroup analysis to investigate if CI of the high-purity, pasteurized, plasma-derived FVIII concentrate Beriate(®) P during surgery increases the risk of inhibitor formation. MATERIALS AND METHODS: Patients with severe haemophilia A (FVIII:C <1%) were included if they presented with a negative history of previous inhibitors, had ≥ 50 exposure days, and had been scheduled for a planned surgical procedure. A bolus infusion (30-50 IU/kg body weight) of Beriate(®) P was administered intravenously and followed by CI at a rate of 3-4 IU/kg body weight/hour. Dose adjustments were subsequently made based on daily measurements of plasma FVIII activity. RESULTS: Five patients (aged 8-34 years) with severe haemophilia A were included. The surgical procedures ranged from teeth extraction to internal fixation of a fracture. There was no inhibitor generation with CI of Beriate(®) P in patients undergoing surgery, and we did not observe any complications due to re-bleeding or virus transmission. CONCLUSION: Beriate(®) P was efficacious, safe, and well tolerated during CI.