We identified 143 monogenic disorders caused by high-penetrance mutations in 89 of the 343 BV-implicated genes (25.9% vs. 16.4% (59 genes) that is expected based on the number of genes reported in OMIM; Fisher exact test P = 2.33 × 10−5) many of which are commonly associated with abnormal brain development (including microcephalia (CDK6), macrocephalia (PTEN) and megalencephaly (AKT3)), and abnormal growth (tetra-amelia syndrome (WNT3)) (Supplementary Data 9). This evidence concerns the gene AKT3 and megalencephaly.