Case Report of Transient Neonatal Hyperparathyroidism: Medically Free Mother

Abstract

Transit neonatal hyperparathyroidism (TNHP) is a very rare recessive mutation in the calcium channel transporter. TNHP is defined as an impairment of calcium transportation from the mother to the fetus prenatally and mainly in the third trimester. TNHP classically presents with skeletal deformities and subsequently affects multiple systems. TNHP has been linked to a mutation in the transient receptor potential cation channel, subfamily V, member 6 (TRPV6). We report a case of a full-term male infant diagnosed with TNHP prenatally from a medically free mother. The patient was discharged home at the age of 28 days after an excellent response to the trial of calcium infusion.

Transient Receptor Potential Vanilloid 6 (TRPV6) Proteins Control the Extracellular Matrix Structure of the Placental Labyrinth

“…The genotype of the maternal part of the placenta is responsible for the pronounced effect on the bone mineralization because the offspring of homozygous Trpv6- deficient females are much more affected than the offspring from heterozygous females [ 1 ]. This is consistent with case reports in humans, where mutations in the Trpv6 gene lead to the hereditary human disease transient neonatal hyperparathyroidism (HRPTTN, OMIM #618188) associated with skeletal abnormalities, dysplasia, and elevated neonatal parathyroid hormone levels [ 14 , 15 , 16 , 17 , 18 ]. Those authors conclude, that similar to the Trpv6 mouse model [ 1 ], Trpv6 mutations in the maternal and fetal parts of the placenta greatly reduce maternal/fetal calcium transport, thereby affecting infant skeletal development and mineralization.…”

Mutations That Affect the Surface Expression of TRPV6 Are Associated with the Upregulation of Serine Proteases in the Placenta of an Infant

“…The human TRPV6 protein is expressed in a few tissues, e.g., pancreatic acini and the trophoblast layer of the placenta. Several recent studies describe new born children who suffer from hyperparathyroidism with undermineralized bones [ 13 , 14 , 15 , 16 , 17 ]. However, the underlying cause of the disease seems to be the TRPV6 gene.…”

“…Whether this polymorphism has a functional consequence is not known. In recent publications, the effects of TRPV6 mutations altering the functionality of TRPV6 channels in humans were published [ 13 , 14 , 15 , 16 , 17 ]. Dysfunction of TRPV6 channels leads to transient neonatal hyperparathyroidism (HRPTTN) and is listed in the OMIM database (Online Mendelian Inheritance in Man).…”