HNF1B and Gerstmann syndrome: GS in approximately 80% to 95% of patients is associated with mutations in SLC12A3 encoding NCCT (thiazide-sensitive Na-Cl cotransporter) (MIM: 263800) [11, 13], and the remaining 5% to 20% of patients with GS-like syndromes may have pathogenic variants in KCNJ10 (KCNJ member-10) encoding Kir4.1, FXYD2 (FXYD-domain containing ion transport regulator-2) encoding sodium/potassium-transporting ATPase subunit-gamma, HNF1B (hepatocyte nuclear factor-1 homeobox-B), or mitochondrial DNA [14-20].