This article delineates a novel syndrome, which was named COFG syndrome with respect to the developmental defects observed: brain malformations, especially affecting the cerebellum, developmental delay and intellectual disability, developmental defects of the external genitals resulting in absence of the scrotum in boys and absence of the labia majora in girls, eye anomalies and distinctive facial features. Malfunction of MAB21L1, a protein of largely unknown function, has been identified as underlying molecular cause using next generation sequencing with all affected individuals, descending from 5 independent families, harbour recessively inherited MAB21L1 loss of function alleles. (By Dr Miriam Schmidts, https://jmg.bmj.com/content/early/2018/11/28/jmedgenet-2018-105623 )