Novel and recurrent TRPV4 mutations and their association with distinct phenotypes within the TRPV4 dysplasia family.

BACKGROUND: Mutations in TRPV4, a gene that encodes a Ca(2+) permeable non-selective cation channel, have recently been found in a spectrum of skeletal dysplasias that includes brachyolmia, spondylometaphyseal dysplasia, Kozlowski type (SMDK) and metatropic dysplasia (MD). Only a total of seven missense mutations were detected, however. The full spectrum of TRPV4 mutations and their phenotypes remained unclear. OBJECTIVES AND METHODS: To examine TRPV4 mutation spectrum and phenotype-genotype association, we searched for TRPV4 mutations by PCR-direct sequencing from genomic DNA in 22 MD and 20 SMDK probands. RESULTS: TRPV4 mutations were found in all but one MD subject. In total, 19 different heterozygous mutations were identified in 41 subjects; two were recurrent and 17 were novel. In MD, a recurrent P799L mutation was identified in nine subjects, as well as 10 novel mutations including F471del, the first deletion mutation of TRPV4. In SMDK, a recurrent R594H mutation was identified in 12 subjects and seven novel mutations. An association between the position of mutations and the disease phenotype was also observed. Thus, P799 in exon 15 is a hot codon for MD mutations, as four different amino acid substitutions have been observed at this codon; while R594 in exon 11 is a hotspot for SMDK mutations. CONCLUSION: The TRPV4 mutation spectrum in MD and SMDK, which showed genotype-phenotype correlation and potential functional significance of mutations that are non-randomly distributed over the gene, was presented in this study. The results would help diagnostic laboratories establish efficient screening strategies for genetic diagnosis of the TRPV4 dysplasia family diseases.

Stature and severity in multiple epiphyseal dysplasia.

We investigated the stature and radiological findings in 15 patients with multiple epiphyseal dysplasia (MED). They were divided into normal-stature and short-stature groups according to their body height after 4 or 5 years of age. Their stature was not related to the involvement of the spine or epiphyses of long tubular bones except for the distal radius. Proximal phalanges and metacarpi were shorter in the short-stature group than in the normal-stature group, indicating that stature in MED had some relationship to the involvement of the wrist and hand. However, some patients in the normal-stature group showed involvement of distal radial epiphyses, and some patients in the short-stature group did not have stubby fingers. There are thus no clear-cut criteria to differentiate between the severe Fairbank type and the milder Ribbing type of MED.

[Two cases of peripartum cardiomyopathy].

Two cases of peripartum cardiomyopathy, a rare type of dilated cardiomyopathy, are reported. A 36-year-old woman developed congestive heart failure 1 month after delivering her third child. Cardiac catheterization revealed diffuse hypokinesis of the left ventricle and an ejection fraction of 28%. The second study, 20 months later, demonstrated an ejection fraction of 46%. Endomyocardial biopsy showed mild interstitial edema. A 42-year-old woman developed toxemia during pregnancy. She delivered her second child at 38 weeks of gestation. Two weeks later, she developed congestive heart failure. Cardiac catheterization demonstrated diffuse hypokinesis of left ventricle with an ejection fraction of 40%. Endomyocardial biopsy revealed dense fibrosis. Follow-up angiography performed 8 months later showed similar findings with an ejection fraction of 34%. These two cases suggest the importance of evaluation of endomyocardial biopsy to determine the degree of interstitial fibrosis that may reflect the prognosis for patients with peripartum cardiomyopathy confirmed by measurements of ejection fraction.

Reaction of hydroxyapatite-sol in bone marrow.

Hydroxyapatite-sol was prepared by dispersing hydroxyapatite microcrystals into saline. The hydroxyapatite microcrystals were synthesized by neutralization reaction of calcium hydroxide suspension and phosphoric acid solution. Sizes of the hydroxyapatite microcrystals were less than 0.1 microns, and the mean value was 0.05 microm. The 0.2 ml hydroxyapatite-sol with a concentration of 14.8 mg/ml was injected into medullary cavities of rat femurs. Both sintered hydroxyapatite powder suspension and saline as comparative materials were injected into the medullary cavities in the same way. Reaction of the hydroxyapatite-sol in the bone medullary cavities was investigated histologically using light and transmission electron microscopes. After 3 days, new bone formation was observed by injection of hydroxyapatite-sol, while no bone formation was observed by injection of sintered hydroxyapatite powder and saline. Osteoblasts were observed endocytosing the hydroxyapatite-sol in the medullary cavities of the rats. Macrophages and undifferentiated osteoblasts were found around the hydroxyapatite-sol aggregation by transmission electron microscope. After 5 days, amounts of new bone increased and matured, forming trabeculae. Many osteoblasts were observed in a line along the surface of the bone. On the other hand, 5 days after injection of sintered hydroxyapatite powder and saline to bone formation was observed while at 10 days after injection, some immature new bone formation started to be observed. New bone increased and matured at 15 days postoperatively. From these results, it was concluded that hydroxyapatite-sol only quickly promotes the formation of new bone in bone marrow and can be used as injection liquid of new biomaterials for bone formation.

A highly topically active corticosteroid. Preliminary report.

The local anti-inflammatory effects of a synthetic corticosteroid, 17 alpha, 21-diacetory-2-bromo-6 beta, 9 alpha-difluoro-11 beta-hydroxy-1,4,-pregnadiene-3,20-dione (F-2), were evaluated by granuloma and granuloma pouch method. F-2 had an intensive and probably persistent topical anti-inflammatory activity. The systemic effects of F-2 were evaluated by measuring the thymus and adrenal gland weight. F-2 did not induce significant systemic effects at as high a dose as 125 times the effective dose.

Calcium uptake, release and Mg-ATPase activity of sarcoplasmic reticulum from arterial smooth muscle.

Sarcoplasmic reticulum (SR) isolated from rat aorta exhibited ATP dependent Ca2+ uptake in the presence of Mg2+. The maximum capacity and apparent binding constant were 23n moles/mg and 1.8 X 10(4) M (-1), respectively. The energy source of this active Ca2+ accumulation would be Mg-ATPase associated with the membrane. Ca2+ which was taken up inside of sarcoplasmic reticulum was released rapidly by washout with the medium containing no Ca2+. These facts suggest that sarcoplasmic reticulum in vascular smooth muscle cell may play and important role in the regulation of intracellular Ca2+ concentration.