 There are only 2 known families, from Dubai and Texas, in which the disease was passed from mother to daughter (Texas), and from a mother to her 2 sons (Dubai).Blood levels of parathyroid hormone (PTH) are undetectable, but the mutation in the PTH1R leads to auto-activation of the signaling as though the hormone PTH is present.Severe JMC produces a dwarfing phenotype, or short stature.