While the exact prevalence of BRPS is unknown, the Deciphering Developmental Disorders study (n = 9,625 ID trios) identified de novo ASXL3 variants in 50 probands (1:193), placing ASXL3 among the top 10 most frequently mutated genes in neurodevelopmental disorders (4). This evidence concerns the gene ASXL3 and severe feeding difficulties-failure to thrive-microcephaly due to ASXL3 deficiency syndrome.