ESPE Abstracts

Background: Parathyroid Hormone (PTH), a key regulator of calcium and phosphorus homeostasis through its effect on bone, kidney, and intestine. The serum concentration of PTH is derived both from the release of PTH stored in secretory granules and from de novo synthesis of PTH in response to alterations in the serum levels of calcium, phosphorus, and vitamin D. Magnesium has a potent role in secretion of PTH, while alkaline phosphatase appears to be important ...

Background: The CYP27B1 gene encodes 25-hydroxyvitamin D-1α-hydroxylase. Mutations of this gene cause a rare autosomal recessive disorder, vitamin D-dependent rickets type 1A.Objective and hypotheses: To investigate CYP27B1 mutations in children when rickets was associated with normal or high vitamin D levels and low or inappropriately normal calcitriol levels.Method: All coding exons and intron-exon boundari...

Hereditary vitamin D-resistant rickets (HVDRR) is an autosomal recessive disorder characterized by end organ resistance to 1α,25-dihydroxyvitamin D3 (1,25D3). The syndrome is recognized by severe early onset rickets with bowing of the lower extremities, short stature, often alopecia and severe hypocalcemia.Objectives: To study the effectiveness of our designed protocol of continuous high dose intracaval calcium infusion for the tre...

Background: Insulin-like growth factor I (IGF-I) is one of the important hormonal mediators of human growth. Circulating IGF-I exists in a ternary complex bound to the acid-labile subunit (ALS) and one of its six binding proteins (BPs). IGF-I bound to ALS and BPs needs to be liberated by either Pregnancy Associated Plasma Protease A (PAPP-A) or A2 (PAPP-A2) to reach its receptor. Stanniocalcin 2 (STC2) is a potent inhibitor of both PAPP-A and PAPP-A2. Genome-wide association s...

Background: Transient neonatal adrenal dysfunction is reported in association with antiretroviral therapy with Lopinavir and Ritonavir. Other drugs have not been tested.Objective and hypotheses: We report on a preterm girl, born 26 weeks gestation, with elevated 17-hydroxyprogesterone (17OHP) at newborn screening. During pregnancy the mother was treated for HIV with Atripla (Efavirenz, Tenofovir, Emtricitabin) and viral load was suppressed. Furthermore t...

Vitamin D dependency rickets type 1B (VDDR-1B) is a rare condition classified as rickets due to inadequate 25-hydroxylation of vitamin D. In this study, we describe rickets and loss-of-function CYP2R1 mutations in 6/10 individuals tested from two unrelated families. Five patients in family 1 (F1) have homozygous L99P mutations; while one member of family 2 (F2) has novel homozygous mutations at G42_L46del insR. The mutations, as well as another variant M248I found in ...

Introduction: Vitamin D resistant rickets type II (VDDR-II) is a disease with a difficult treatment developed as a result of mutations in VDR gene. Despite high dose active vitamin D and oral calcium treatments, sufficient recovery cannot be achieved mostly. Successful results with intravenous calcium infusion that is an alternative treatment have been reported; however, serious restrictions and complications such as hospitalization, catheter infection, thrombosis, skin necros...

Background & Aim: Vitamin D-dependent rickets type 1 A (VDDR1A) is an autosomal recessive condition caused by mutation in CYP27B1, which encodes 1 α-hydroxylase enzyme that catalyzes the conversion of 25-hydroxyvitamin D (25OHD) to 1,25-dihydroxyvitamin D (1,25 (OH)2D). We are reporting 4 cases of VDDR1A due to CYP27B1 mutation initially misdiagnosed as vitamin D deficient and hypophosphatemic rickets.<p class="abstext...

Background: CYP27B1 converts 25-hydroxyvitamin D3 to active 1,25-dihydroxyvitamin D3, playing a vital role in calcium homeostasis and bone growth. Vitamin D-dependent rickets type 1 (VDDR-1) is a rare autosomal recessive disorder caused by mutations in CYP27B1.Objective and hypotheses: Enzymatic and structural analysis of mutations in a patient with calcipenic rickets.Method: Two siblings presented with calcip...

Background: N-methyl-D-aspartate receptors (NMDARs) are ionotropic glutamate receptors that are widely expressed in the CNS where they play an important role in neurotransmission and cell viability and serve as drug targets for the treatment of neurodegenerative disorders.Objective and hypotheses: Much less is known about the role of pancreatic NMDARs. Since neurons and pancreatic islets have many features in common, we hypothesiz...