Biomedical subjects

Takuo Kubota

Publications and source records attributed to Takuo Kubota.

7 recordsLinked to original sources

PubMed2026

A Phase 3 Trial of Vosoritide in Children with Hypochondroplasia.

BACKGROUND: Hypochondroplasia, a fibroblast growth factor receptor 3 (FGFR3)-related skeletal condition characterized by disproportionate short stature and a spectrum of clinical features, has no available targeted therapies. Vosoritide, a C-type natriuretic peptide analogue approved for the treatment of achondroplasia, is being investigated for hypochondroplasia. METHODS: In this phase 3, multicenter trial, children with hypochondroplasia who were 3 to less than 18 years of age were randomly assigned to receive once-daily subcutaneous injections of vosoritide or placebo for 52 weeks per weight-band dosing regimen. The primary end point was change from baseline in annualized growth velocity at week 52 versus placebo. Confirmatory statistical testing using hierarchical procedures to control for type I error at the one-sided 0.025 significance level (equivalent to the two-sided 0.05 level) was performed for the primary and six key secondary efficacy end points. The safety and side effect profile of vosoritide versus placebo was assessed. RESULTS: A total of 81 participants were randomly assigned to receive vosoritide (n=41) or placebo (n=40). At week 52, the least squares mean (LSM) change from baseline in annualized growth velocity was 1.95 cm/year with vosoritide versus -0.39 cm/year with placebo (LSM difference of 2.33 cm/year; 95% confidence interval, 1.85-2.82 cm/year; two-sided P<0.0001). Most participants in the vosoritide group (87.8%) and the placebo group (72.5%) experienced at least one adverse event (AE). There were no reports of grade 3 or higher AEs, AEs leading to treatment discontinuation, or deaths. CONCLUSIONS: One year of vosoritide treatment significantly increased linear growth in children with hypochondroplasia. (Funded by BioMarin Pharmaceutical; ClinicalTrials.gov number, NCT06455059.).

Journal Article↗

PubMed2026

Pierson syndrome with numerous dilated tubules masquerading as autosomal recessive polycystic kidney disease: a case report.

Pierson syndrome, characterized by congenital nephrotic syndrome, ocular abnormalities, and neurological defects, is caused by biallelic pathogenic variants in LAMB2. LAMB2 encodes laminin β2, a key component of basement membranes that is predominantly expressed in the glomeruli, eyes, and neuromuscular junctions. The renal histopathology of Pierson syndrome typically shows diffuse mesangial sclerosis (DMS), with occasional tubulointerstitial atrophy and fibrosis. We report a case of Pierson syndrome characterized by DMS and prominent tubular dilatation. A fetal ultrasound at 23 weeks of gestation revealed hyperechoic kidneys, which gradually enlarged, accompanied by the onset of anhydramnios from 31 weeks. The patient was delivered at 39 weeks of gestation, weighing 3,132 g, without placentomegaly. Postnatal respiratory failure due to pulmonary hypoplasia required extracorporeal membrane oxygenation, and hemodialysis was initiated for anuria. Left nephrectomy was performed on day 8 of life, revealing replacement of the renal parenchyma by numerous irregularly dilated tubules with eosinophilic casts. The right kidney reached maximal enlargement by 1 month of age and subsequently began to shrink. Ocular findings included bilateral microcoria and cataracts. Whole-exome sequencing identified compound heterozygous truncating variants in LAMB2 (p.Gln1507Ter and p.Gln1622Ter). This case highlights the need to consider Pierson syndrome in the differential diagnosis of prenatally detected hyperechoic and enlarged kidneys, in addition to polycystic kidney disease.

Female↗

PubMed2004

Skeletal defects in ringelschwanz mutant mice reveal that Lrp6 is required for proper somitogenesis and osteogenesis.

Here, we present evidence that Lrp6, a coreceptor for Wnt ligands, is required for the normal formation of somites and bones. By positional cloning, we demonstrate that a novel spontaneous mutation ringelschwanz (rs) in the mouse is caused by a point mutation in Lrp6, leading to an amino acid substitution of tryptophan for the evolutionarily conserved residue arginine at codon 886 (R886W). We show that rs is a hypomorphic Lrp6 allele by a genetic complementation test with Lrp6-null mice, and that the mutated protein cannot efficiently transduce signals through the Wnt/beta-catenin pathway. Homozygous rs mice, many of which are remarkably viable, exhibit a combination of multiple Wnt-deficient phenotypes, including dysmorphologies of the axial skeleton, digits and the neural tube. The establishment of the anteroposterior somite compartments, the epithelialization of nascent somites, and the formation of segment borders are disturbed in rs mutants, leading to a characteristic form of vertebral malformations, similar to dysmorphologies in individuals suffering from spondylocostal dysostosis. Marker expression study suggests that Lrp6 is required for the crosstalk between the Wnt and notch-delta signaling pathways during somitogenesis. Furthermore, the Lrp6 dysfunction in rs leads to delayed ossification at birth and to a low bone mass phenotype in adults. Together, we propose that Lrp6 is one of the key genetic components for the pathogenesis of vertebral segmentation defects and of osteoporosis in humans.

Aging↗

PubMed2004

[Regulation of bone mineralization by enzymes].

The enzymes, such as TNSALP regulate bone mineralization, and the mineralization inhibitor inorganic pyrophosphate (PPi) plays a central role in the process. NPP1 and ANK increase PPi concentration in the extracellular matrix, while TNSALP hydrolyzes PPi. The analyses using knock-out mice demonstrated that NPP1 and ANK, and TNSALP are antagonistic regulators for PPi. Concerted regulation of PPi by TNSALP, NPP1, and ANK, leads bone mineralization to be regulated strictly.

Alkaline Phosphatase↗

PubMed2003

[Not Available].

Explore the source record for details and available documents.

Journal Article↗

PubMed2003

[Osteoporosis associated with gene mutation].

Osteoporosis is the most common metabolic bone disease and caused by multiple nutritional, environmental and genetical factors. Bone mineral density (BMD) is rather strongly under genetical control. A number of candidate genes have been studied with respect to the impact on BMD. Also, gene loci of susceptibility genes for osteoporosis have been identified by family-based association and linkage approaches. In particular, LRP5 is an important molecule involved in the determination of BMD, because its abnormality is associated with osteoporosis-pseudoglioma syndrome or autosomal dominant syndrome characterized by high bone density. These findings may contribute to new strategy to teat patients with osteoporosis.

English Abstract↗

PubMed2002

Development of hyperthyroidism in a patient with idiopathic nephrotic syndrome.

We present a 13-year-old boy who developed hyperthyroidism during the clinical course of idiopathic nephrotic syndrome treated with glucocorticoid. He had a second relapse of minimal change nephrotic syndrome, and complete remission of nephrotic syndrome was achieved immediately with oral glucocorticoid. However, when the steroid dosage was reduced, signs of hyperthyroidism such as systolic hypertension and tachycardia were observed. Laboratory findings revealed thyroid-stimulating hormone (TSH) below 0.05 microU/ml, free tri-iodothyronine of 16.1 pg/ml, free thyroxine of 5.6 ng/dl, and anti-TSH receptor antibody of 90%. Thus, a diagnosis of hyperthyroidism was made and treatment with thiamazol was started. Massive proteinuria may decrease the activity of hyperthyroidism due to urinary loss of thyroid hormones. A decrease in glucocorticoid dosage may also be involved in the development of hyperthyroidism due to a reduced immunosuppressive effect.

Administration, Oral↗