Parathyroid hormone (PTH) plays an essential role in regulating calcium and bone homeostasis in the adult, but whether PTH is required at all for regulating fetal-placental mineral homeostasis and skeletal development is uncertain. We hypothesized that despite its low circulating levels during fetal life, PTH plays a critical role in regulating these processes. To address this, we examined two different genetic models of PTH deficiency. Pth null mice have enlarged parathyroids that are incapable of making PTH, whereas Gcm2 null mice lack parathyroids but have PTH that arises from the thymus. Pth nulls served as a model of complete absence of PTH, whereas Gcm2 nulls were a model of severe hypoparathyroidism. We determined that PTH contributes importantly to fetal mineral homeostasis because in its absence a fetal hypoparathyroid phenotype results with hypocalcemia, hypomagnesemia, hyperphosphatemia, low amniotic fluid mineral content, and reduced skeletal mineral content. We also determined that PTH is expressed in the placenta, regulates the placental expression of genes involved in calcium and other solute transfer, and may directly stimulate placental calcium transfer. Although parathyroid hormone-related protein (PTHrP) acts in concert with PTH to regulate fetal mineral homeostasis and placental calcium transfer, unlike PTH, it does not upregulate in response to fetal hypocalcemia. ß
Consent processes for newborn bloodspot screening (NBS) are variable, with a lack of descriptive research that depicts how the offer of NBS is made to parents. We explored the experience, in practice, of consent for NBS. Semistructured interviews in two Canadian provinces were held with: (1) parents of children offered NBS (n = 32); and (2) health-care professionals involved in the NBS process (n = 19). Data on recollections of NBS, including consent processes, were utilized to identify emerging themes using the method of constant comparison. Three themes were relevant to NBS consent: (1) The 'offer' of NBS; (2) content and timing of information provision; and (3) the importance of parental experiences for consent decisions. Recollections of consent for NBS were similar between jurisdictions. Excepting midwives and their patients, NBS was viewed as a routine part of giving birth, with little evidence of an informed consent process. Although most parents were satisfied, all respondents suggested information about NBS be provided long before the birth. Accounts of parents who declined screening highlight the influence of parental experiences with the heel prick process in screening decisions. Findings further our understanding of consent in practice and highlight areas for improvement in parent-provider interactions.
Aim: To survey the general public about whole genome sequencing interest, including pharmacogenomic testing, and to identify information important for sequencing decisions. Patients & methods: An online survey of 901 members of the general public in an Eastern Canadian province. Results: Interest in whole genome sequencing, including pharmacogenomic testing, was high with few differences among demographic variables. Issues identified as very important to sequencing decisions included familial implications of testing, whether treatment was available for conditions tested and knowing who could access genomic information. Most respondents would value support when interpreting sequencing results. Conclusion: Findings reveal the kind of information and support users of sequencing services would value and could inform the implementation of sequencing into care in ways that accord with public preferences and needs.
<b><i>Introduction:</i></b> The growth of global sequencing initiatives and commercial genomic test offerings suggests the public will increasingly be confronted with decisions about sequencing. Understanding public attitudes can assist efforts to integrate sequencing into care and inform the development of public education and outreach strategies. <b><i>Methods:</i></b> A 48-item online survey was advertised on Facebook in Eastern Canada and hosted on SurveyMonkey in late 2018. The survey measured public interest in whole genome sequencing and attitudes toward various aspects of sequencing using vignettes, scaled, and open-ended items. <b><i>Results:</i></b> While interest in sequencing was high, critical attitudes were observed. In particular, items measuring features of patient control and choice regarding genomic data were strongly endorsed by respondents. Majority wanted to specify upfront how their data could be used, retain the ability to withdraw their sample at a later date, sign a written consent form, and speak to a genetic counselor prior to sequencing. Concerns about privacy and unauthorized access to data were frequently observed. Education level was the sociodemographic variable most often related to attitude statements such that those with higher levels of education generally displayed more critical attitudes. <b><i>Conclusions:</i></b> Attitudes identified here could be used to inform the development of implementation strategies for genomic medicine. Findings suggest health systems must address patient concerns about privacy, consent practices, and the strong desire to control what happens to their genomic data through public outreach and education. Specific oversight procedures and policies that are clearly communicated to the public will be required.
Parathyroid hormone (PTH) and PTH-related protein (PTHrP) play complementary and overlapping roles in regulating fetal mineral homeostasis. PTHrP is expressed within the growth plate, directs endochondral bone formation, and determines the fate of chondrocytes before bone formation can be initiated. It is expressed in placenta and is present at high levels in the fetal circulation. It stimulates placental calcium (and possibly magnesium) transfer and raises blood mineral levels above ambient maternal values in order to effect mineralization of the skeleton. It does not upregulate in response to absence of PTH or hypocalcemia, and thus, its secretion may be regulated autonomously or in response to placental signals. PTH is expressed in fetal parathyroids and placenta. Despite circulating at low levels, it has a more dominant effect than PTHrP in regulating the blood calcium and ensuring adequate mineralization of the skeleton. It may also have effects on bone formation in the steps that occur after apoptosis of hypertrophic chondrocytes. Unlike PTHrP, it increases with fetal hypocalcemia, but its secretion is constrained by the calcium-sensing receptor to maintain the adult calcium level, well below what the fetus normally achieves. PTH also stimulates placental calcium transfer, and its absence disrupts placental expression of calciotropic and cation transporter genes.
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