Intellectual Developmental Disorder with Speech Delay, Dysmorphic Facies, and T-Cell Abnormalities, also known as intellectual developmental disorder with dysmorphic facies, speech delay, and t-cell abnormalities, is related to immune deficiency disease. An important gene associated with Intellectual Developmental Disorder with Speech Delay, Dysmorphic Facies, and T-Cell Abnormalities is BCL11B (BCL11 Transcription Factor B). Related phenotypes are intellectual disability and delayed speech and language development