The patient was shown to have a heterozygous deletion chr1:238817161-249224684 removing AKT3. All previously reported variants in AKT3 causing Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 2 are missense gain of function variants so we propose the first loss of function variant causing microcephaly instead of megalencephaly as part of a new AKT3-related neurodevelopmental disorder. The gene discussed is AKT3; the disease is megalencephaly.