Neurologic phenotypes associated with COL4A1/2 mutations: expanding the spectrum of disease

Objective: To characterize the neurological phenotypes associated with COL4A1/2 mutations and to seek genotype-phenotype correlation.
Methods We analyzed clinical, EEG and neuroimaging data of 44 new, and 55 previously reported patients with COL4A1/COL4A2 mutations.
Results Childhood-onset focal seizures, frequently complicated by status epilepticus and resistance to anti-epileptic drugs, was the most common phenotype. EEG typically showed focal epileptiform discharges in the context of other abnormalities, including generalized sharp waves or slowing. In 46.4% of new patients with focal seizures, porencephalic cysts on brain MRI co-localized with the area of the focal epileptiform discharges. In patients with porencephalic cysts, brain MRI frequently also showed extensive white matter abnormalities, consistent with the finding of diffuse cerebral disturbance on EEG. Notably, we also identified a subgroup of patients with epilepsy as their main clinical feature, in which brain MRI s...