Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “HYPOPHOSPHATEMIA, FAMILIAL”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,063 records · Page 59Linked to original sources
PubMedDate not supplied

Nephrocalcinosis in children and adolescents: sonographic evaluation during long-term treatment with 1,25-dihydroxycholecalciferol.

In order to study the presence of possible renal damage, 12 patients who had been chronically treated with 1,25-dihydroxycholecalciferol therapy, 1,25(OH)2D3, for hypoparathyroidism, pseudohypoparathyroidism, and hypophosphatemic rickets were examined by renal ultrasound. Two patients had normal values while 10 subjects showed nephrocalcinosis (NC) of mild, medium, or severe degree. The echographic results have been related to some calcium-phosphorus metabolism and therapeutic parameters. In those subjects with medium to severe NC, the age at the beginning of therapy was significantly younger and the dose of 1,25(OH)2D3 was significantly higher, than in the other patients. Laboratory data were not predictive of NC. Renal ultrasound is, therefore, a useful means of screening to detect even early stages of NC; its use in the follow-up is also recommended.

Adolescent↗
PubMed1985

Vitamin D-dependent rickets types I and II. Diagnosis and response to therapy.

The diagnostic value of measuring serum vitamin D metabolites is demonstrated in the present study in which two patients with vitamin D-dependent rickets (VDDR) Types I and II are reported. The patient with sporadic VDDR Type I was severely disabled and unable to walk. Her serum 1,25(OH)2D level was low (32 pg/ml, normal 30 to 60) and she responded dramatically to 1 microgram of 1 alpha-hydroxyvitamin D3 daily. The VDDR Type II patient had an autosomal recessive inheritance and total alopecia. His serum 1,25(OH)2D level was greater than 500 pg/ml, compatible with end-organ refractoriness to 1,25(OH)2D. He did not respond to daily doses of 1 microgram 1 alpha-hydroxyvitamin D3. These cases demonstrate the striking difference in 1,25(OH)2D levels and therapeutic response to 1,25(OH)2D in these two conditions.

Adult↗
PubMed1985

Vitamin D-dependent calcium transport.

Vitamin D must be metabolized to 25-OH-D3 or calcidiol in the liver and subsequently to 1,25-(OH)2D3 (calcitriol) in the kidney to produce its physiological actions. Calcitriol stimulates calcium and phosphorus transport reactions in the small intestine and together with parathyroid hormone stimulates calcium transport reactions in bone and kidney. In the small intestine calcitriol brings about its response in a complex manner. It provides a very rapid response on existing villus cells, causing a rise in calcium transport within 6 h postadministration. This transport response subsides by 18 h, and a second response makes its appearance at 24-48 h. This second response is likely to be an action on crypt cells which then migrate into the villus region and bring about calcium transport. The molecular mechanism of calcium transport in the villus cells has been examined. Calcitriol localizes specifically in the nucleus within 0.5 h postadministration, and it does not localize in any of the other cell fractions. A receptor has been discovered for calcitriol, and interaction with this receptor is required for calcitriol to bring about its action in stimulating calcium transport. It is therefore believed that calcitriol, together with receptor, binds to specific portions of nuclear DNA to bring about transcription of specific genes that code for calcium and phosphorus transport proteins. Only one protein induced by calcitriol has been described. It is the calcium-binding protein found in the cytoplasm. Exactly how it functions in calcium transport is in debate, although the time sequence of its appearance appears to be consistent with a role in that system. It is likely that other gene products are induced by calcitriol, and they are currently being characterized. In the neonatal rat, active calcium transport does not make its appearance until 14-16 days postpartum. The intestine is not sensitive to vitamin D or calcitriol prior to this time. This lack of sensitivity is because of the lack of a receptor for calcitriol. The receptor to calcitriol can be precociously induced by hydrocortisone injections, or it can be delayed by adrenalectomy. Incubation of intestine from neonatal rat pups at 14 days postpartum with hydrocortisone brings about in vitro appearance of the receptor molecule. These results and results of studies involving genetic vitamin D resistance strongly suggest that calcitriol must function by interaction with the receptor, presumably by a nuclear mechanism, to bring about intestinal calcium transport. The molecular mechanism, however, remains to be described.

Animals↗
PubMed1985

Calcitriol-resistant rickets with alopecia.

Four children of two kindred had alopecia associated with severe rickets, resistant to treatment, and caused by defective cytoplasmic and nuclear receptors for the active vitamin D metabolite calcitriol (1,25-dihydroxyvitamin D3). Scalp biopsy specimen revealed a normal number and light microscopic features of the hair and hair follicles. Calcitriol-resistant rickets should be added to the list of inherited disorders of hair growth, and the association of rickets with alopecia needs to be considered in the differential diagnosis of hair loss.

Alopecia↗
PubMed1985

Hypophosphatemic rickets: still misdiagnosed and inadequately treated.

We studied the presentation and results of medical therapy in 25 children with sex-linked dominant hypophosphatemic rickets. The average age at diagnosis was 3.8 years. Reasons for the delay included misdiagnosis and failure to recognize the normal range of serum phosphorus levels in children. Early diagnosis and treatment (before age 1) was associated with normal alignment of the lower limbs. Combination therapy with phosphate and vitamin D2 improved growth and bone mineralization, but did not change the height percentile or limb alignment. Limited use of calcitriol (1,25-dihydroxyvitamin D3) was not helpful in the adolescent but was associated with limited height increase in two younger children. Early diagnosis and medical therapy should prevent bowing of the legs.

Adolescent↗
PubMedDate not supplied

[Biological and bone histomorphometric studies in hypophosphatemic vitamin-resistant rickets treated with 1,25-(OH)2D and phosphorus].

Five children aged 6 to 15 years were studied. They presented all the biological signs of hypophosphatemic vitamin resistant rickets: normal calcemia, hypophosphatemia, decrease in phosphorus Tm and normal PTH plasma level. Two children had never been given vitamin D treatment previously. The 1.25 (OH)2D has been given in 4 doses a day, to a total of 1 microgram/day, for one year. Phosphate was administered for the same time, doses varying from 40 to 150 mg/kg/day. Bone biopsies were performed at the onset and the end of treatment. Normal growth concerning bone age was observed in 3 cases. In the two others, growth remained disturbed. Radiological recovery was observed in all cases. Treatment induced and increase in serum phosphate. Tm PO4/FG remained lower than normal and even decreased during treatment. After one year of treatment, the osteoid volumes and surfaces decreased in all cases but did not always return to normal. The thickness index of osteoid and the speed of calcification were improved in 4 cases and worsened in the 5th. In two previously untreated patients an increase in plasma PTH and in the osteoclastic surface of resorption were observed on the bone biopsy during treatment.

Adolescent↗
PubMedDate not supplied

Hereditary hypophosphatemia rickets: an important awareness for dentists.

Because X-linked hypophosphatemia VDRR is reported to be the most common form of rickets in the United States today, it is important for dentists to be aware of this condition. Characteristic dental findings are often the first clinically noticeable signs of the disease. The confirmation of hypophosphatemia with dental findings will permit early diagnosis and prevent crippling rachitic deformities, otherwise certain to follow. Reports in the literature confirm the validity of conservative, prophylactic full coverage restorations in patients with VDRR.

Child↗