ARHGAP4 and nephrogenic diabetes insipidus: It encodes a 3.5 kb mRNA and a 946 amino acid protein.[11] The ARHGAP4 mRNA is highly expressed during development and in the adult central nervous system.[12]ARHGAP4 has been identified as a causative factor linked with a new phenotype characterized by nephrogenic diabetes insipidus, psychomotor delays, and short stature (Online Mendelian Inheritance in Man).