abnormal x-zone morphology abnormal adrenal gland x-zone size MP:0020143 2014-04-29T00:00:00Z nvasilevsky abnormal adrenal gland x zone size an anomaly in the size of the x-zone compared to the average on the pair of endocrine glands located above the kidney that are responsible for steroid hormone secretion from the cortex and neurotransmitter (such as epinephrine and norepinephrine) secretion from the medulla MPheno.ontology