Genomic Medicine: Lessons Learned From Monogenic and Complex Bone Disorders.

Current genetic studies of monogenic and complex bone diseases have broadened our understanding of disease pathophysiology, highlighting the need for medical interventions and treatments tailored to the characteristics of patients. As genomic research progresses, novel insights into the molecular mechanisms are starting to provide support to clinical decision-making; now offering ample opportunities for disease screening, diagnosis, prognosis and treatment. Drug targets holding mechanisms with genetic support are more likely to be successful. Therefore, implementing genetic information to the drug development process and a molecular redefinition of skeletal disease can help overcoming current shortcomings in pharmaceutical research, including failed attempts and appalling costs. This review summarizes the achievements of genetic studies in the bone field and their application to clinical care, illustrating the imminent advent of the genomic medicine era.

Acromesomelic Dysplasia, Type Maroteaux: Impact of Long-Term (8 Years) High-Dose Growth Hormone Treatment on Growth Velocity and Final Height in 2 Siblings.

INTRODUCTION: Acromesomelic dysplasia, type Maroteaux (AMDM) is a rare autosomal recessive skeletal dysplasia, characterized by severe dwarfism and disproportionate limb shortening. It results from loss-of-function NPR2 mutations affecting the C-type natriuretic peptide receptor. Resistance to growth hormone (GH) action has previously been suggested. We describe outcomes of 2 siblings with AMDM after prolonged high-dose GH treatment. PATIENTS/METHODS: Two siblings (Pt-A and Pt-B; consanguineous parents) presented in early childhood with severe disproportionate short stature and radiological features of AMDM. Subsequent genetic testing identified a novel homozygous NPR2 mutation. GH provocation testing showed relatively high GH levels. Serum insulin-like growth factor 1 (IGF-1) was ∼2 SD below age/sex-specific mean. High-dose GH (0.075 mg/kg/day) was started. Pre-GH height velocities were 3.7 (Pt-A) and 4.5 (Pt-B) cm/year. GH dose was adjusted to sustain serum IGF-1 towards +3 SDS for age/sex. Annualized height velocities for first 3 years on GH were 7.0, 5.4, and 4.7 cm/year for patient A and 9.4, 8.0, and 5.9 cm/year for patient B. Height gain during puberty was 10.6 (Pt-A) and 5.9 (Pt-B) cm. Final heights after 8.5 years of GH treatment were 130.5 cm (-6.57 SDS, Pt-A) and 134 cm (-4.58 SDS, Pt-B). CONCLUSIONS: To the best of our knowledge, this is the first report of final height in patients with AMDM after long-term GH treatment. Our results confirm the finding of relative GH resistance in AMDM, which when overcome with high-dose GH treatment resulted in improved height SDS during childhood and adolescence and associated quality of life. The final height of our patients was significantly higher than average reported final height (120 cm) of AMDM patients.

Pediatric radiology in the diagnosis and management of skeletal dysplasias - welcome to the era of genomic medicine and modern drug pipelines.

Radiologists have long played a key role in the diagnosis and management of children with suspected skeletal dysplasia. Advancing molecular sciences, including the emergence of next generation sequencing and the development of modern rapid drug pipelines have the potential to transform this role.

Comprehensive LC-MS/MS-based phytochemical perspectives and osteogenic effects of Uraria crinita.

Osteogenesis plays a vital role in the maintenance of bone health. Imbalances in osteogenesis influence the onset of several bone loss-associated diseases. The intake of Uraria crinita (Fabaceae) through dietary supplements is advised for childhood bone dysplasia. This botanical provides edible tonics and detoxifiers, and is also used as a folk beverage. We evaluated the osteogenic effects of a 50% ethanol extract of the root of U. crinita on primary human osteoblasts (HObs) and initiated a novel comprehensive phytochemical strategy using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for quality control of this functional food. Two isoflavones, genistein (5) and 5,7-dihydroxy-3',5'-dihydroxyisoflavone (6), increased the alkaline phosphatase activity (differentiation stage); the flavone glycoside vitexin (1), and the phenolic acid salicylic acid (2) enhanced the mineralization (mature stage). The isoflavone 2'-hydroxygenistein (4) possessed high osteogenic potential among the isolated compounds in HObs. It promoted osteogenesis-related stages and upregulated the gene expressions in a dose-dependent manner. The major compounds in the active fraction were quantitatively analyzed via phytochemical fingerprint detection. These LC-MS/MS-based phytochemical perspectives can act as reference standards in developing food supplements from U. crinita.

Fibrous dysplasia of the orbital region: Series of 12 cases and review of the literature.

PURPOSE: Fibrous dysplasia (FD) is a benign fibro-osseous developmental disorder of growing bone, sometimes involving the craniofacial skeleton (CFD). We wish to present a patient series with CFD of the orbital region and discuss treatment modalities. METHODS: Twelve patients were referred for orbital CFD in the Nantes University Hospital between 2000 and 2018 and studied according to the clinical parameters, radiological features, and modalities of treatment. RESULTS: The mean age was 25.6 years. Ten patients exhibited facial asymmetry with vertical globe dystopia (75%), proptosis (58%) and facial bump (50%). The disease was monostotic in 83% of patients, involving the frontal bone (25%), the sphenoidal bone (33%), the fronto-sphenoidal complex (25%), and the skull base (17%). Unilateral radiological proptosis was found in 7 patients, with a mean protrusion 3.9mm. The optic canal was involved in 75% of patients, with no functional impairment. Three patients were treated with bisphosphonate therapy to stop progression of the disease; 6 patients were given a bone remodelling procedure with good aesthetic outcomes. CONCLUSION: The orbit is a rare localization for FD causing aesthetic and functional disabilities. Medical and surgical treatment can be proposed as part of a multidisciplinary approach.

Growth hormone receptor promotes osteosarcoma cell growth and metastases.

Osteosarcoma (OS) is the primary bone malignancy in children and adolescents, with a high incidence of lung metastasis and poor prognosis. Here, we report that growth hormone receptor (GHR) is overexpressed in OS samples compared with osteofibrous dysplasia. We subsequently demonstrated that GHR knockdown inhibited colony formation, promoted cell apoptosis and decreased the number of cells at G2/M phase in 143B and U2OS cells. Furthermore, knockdown of GHR inhibited tumor growth in vivo. Together, these findings indicate that GHR modulates cell proliferation and metastasis through the phosphoinositide 3-kinase/AKT signaling pathway and may be suitable for use as a putative biomarker of OS.

Cortisol Levels in Glucagon Stimulation Test in Children Assessed for Short Stature: Clinical and Laboratorial Correlations.

To assess total cortisol levels in children being evaluating for short stature with normal cortisol reserve and to correlate this response to clinical and laboratory data. Children assessed with glucagon test in our department were recruited in this study retrospectively. Inclusion criteria were: i) age>1 year, ii) absence of chronic illness or medication interfering with ACTH-cortisol axis, iii) GH stimulation levels>3ng/mL at least in one provocation test (glucagon or clonidine), iv) absence of multiple pituitary growth hormone deficiencies, v) normal short Synacthen test in cases of low cortisol response in glucagon test.Two hundred and thirty-seven subjects (160 males, 67.5%) with a mean age of 9.02±3.19 years, were finally included in the analysis. Cortisol peak levels but not cortisol AUC were significantly increased in females compared to males (26.83±7.31 µg/dl vs. 24.04±7.20 µg/dl). When linear correlations were studied, both cortisol peak levels and cortisol AUC were linearly but inversely correlated to age (r=-0.234, p<0.001 and r=-0.315, p<0.001, respectively). Finally, cortisol AUC was inversely correlated to weight Z-scores (r=-0.160, p=0.014). When our analysis was limited only to subjects with intact GH response (GH peak> 7 ng/mL), age was still inversely correlated to cortisol AUC (r=-0.312, p<0.001), and cortisol AUC was linearly correlated to GH AUC assessed with clonidine test (r=0.223, p=0.013). Girls, younger and thinner children exhibit higher cortisol response to glucagon test.

Long-term treatment with anakinra and canakinumab resolves patellar subchondral erosion in neonatal-onset multisystem inflammatory disease.

Not available.

A chinese boy with geleophysic dysplasia caused by compound heterozygous mutations in ADAMTSL2.

Geleophysic dysplasia, belonging to the group of acromelic dysplasia, is a rare genetic disease. Two genes, FBN1 and ADAMTSL2, were known to be linked to this disorder. The disorder presents as extreme short stature, short limbs, small hands and feet, stubby fingers and toes, joint stiffness, toe walking, skin thickening, progressive cardiac valvular thickening and characteristic facial features, including a round face with full cheeks. Here, we report the first Chinese case with geleophysic dysplasia type 1 based on clinical and genetic features. The boy was admitted because of severe physical growth retardation and mild motor retardation. Comprehensive medical evaluations were performed including metabolic studies, endocrine function examination, bone X-rays and echocardiography. Much delayed bone age and geleophysic dysplasia were found. Targeted next-generation sequencing was used to detect genetic mutations associated with skeletal dysplasia. Sanger sequencing was used to confirm the mutations in the patient. PCR amplification, cloing, and sequencing was used to determine the de novo mutation origin. Two compound heterozygous mutations were confirmed in the ADAMTSL2 gene of the patient. The c.340G > A (p.Glu114Lys) mutation was a de novo heterozygous mutation, and our results suggested that it was located on the paternal allele. While the c.234-2A > G inherited from his mother was a novel pathogenic heterozygous splicing mutation. Growth hormone deficiency had been observed in the patient. His growth velocity was improved by growth hormone supplementation. In conclusion, we have identified a novel splicing mutation of ADAMTSL2 carried by a Chinese boy with geleophysic dysplasia type 1. The patient was treated effectively with growth hormone supplementation.

Skeletal Dysplasias: What Every Bone Health Clinician Needs to Know.

PURPOSE OF REVIEW: This review highlights how skeletal dysplasias are diagnosed and how our understanding of some of these conditions has now translated to treatment options. RECENT FINDINGS: The use of multigene panels, using next-generation sequence technology, has improved our ability to quickly identify the genetic etiology, which can impact management. There are successes with the use of growth hormone in individuals with SHOX deficiencies, asfotase alfa in hypophosphatasia, and some promising data for c-type natriuretic peptide for those with achondroplasia. One needs to consider that a patient with short stature has a skeletal dysplasia as options for management may be available.

[Bullous Sweet's syndrome with pulmonary involvement]. / Bullöses Sweet-Syndrom mit pulmonaler Beteiligung.

Acute febrile neutrophilic dermatosis (Sweet's syndrome) is a rare dermatosis characterized by painful papules and plaques accompanied by cutaneous infiltration with neutrophilic granulocytes. Bullous changes are observed in some cases. We report about a patient with osteomyelofibrosis who developed fever accompanied by painful plaques and confluent papules on both arms and thighs. The course of the disease was complicated by blistering and pulmonary infiltrates. After the diagnosis of bullous Sweet's syndrome was established, systemic therapy with glucocorticoids was successful in treating skin lesions and dyspnea.

Dietary phosphate supplement does not rescue skeletal phenotype in a mouse model for craniometaphyseal dysplasia.

BACKGROUND: Mutations in the human progressive ankylosis gene (ANKH; Mus musculus ortholog Ank) have been identified as cause for craniometaphyseal dysplasia (CMD), characterized by progressive thickening of craniofacial bones and flared metaphyses of long bones. We previously reported a knock-in (KI) mouse model (Ank KI/KI) for CMD and showed transiently lower serum phosphate (Pi) as well as significantly higher mRNA levels of fibroblast growth factor 23 (Fgf23) in Ank KI/KI mice. FGF23 is secreted by bone and acts in kidney to promote Pi wasting which leads to lower serum Pi levels. Here, we examined whether increasing the Pi level can partially rescue the CMD-like skeletal phenotype by feeding Ank +/+ and Ank KI/KI mice with high Pi (1.7 %) diet from birth for 6 weeks. We studied the Pi metabolism in Ank KI/KI mice and CMD patients by examining the Pi regulators FGF23 and parathyroid hormone (PTH). RESULTS: High Pi diet did not correct CMD-like features, including massive jawbone, increased endosteal and periosteal perimeters and extensive trabeculation of femurs in Ank KI/KI mice shown by computed microtomography (µCT). This unexpected negative result is, however, consistent with normal serum/plasma levels of the intact/active form of FGF23 and PTH in Ank KI/KI mice and in CMD patients. In addition, FGF23 protein expression was unexpectedly normal in Ank KI/KI femoral cortical bone as shown by immunohistochemistry despite increased mRNA levels for Fgf23. Renal expression of genes involved in the FGF23 bone-kidney axis, including mFgfr1, mKlotho, mNpt2a, mCyp24a1 and m1αOHase, were comparable between Ank +/+ and Ank KI/KI mice as shown by quantitative real-time PCR. Different from normal FGF23 and PTH, serum 25-hydroxyvitamin D was significantly lower in Ank KI/KI mice and vitamin D insufficiency was found in four out of seven CMD patients. CONCLUSIONS: Our data suggests that FGF23 signaling and Pi metabolism are not significantly affected in CMD and transiently low Pi level is not a major contributor to CMD.

Metaphyseal osteopathy in three Australian Kelpie siblings.

CASE REPORT: Metaphyseal osteopathy (MO) was diagnosed in three Australian Kelpie puppies that were presented for veterinary assessment of lameness. The three puppies were siblings. Each was from a different litter by the same breeding pair. The puppy in case one was seen by the authors, and the puppies in cases two and three were patients at other veterinary hospitals. However, the medical records and radiographs were examined and reviewed for this report. Radiographic investigation of the lameness revealed pathognomonic appearance of MO affecting the metaphyseal region of the long bones in all three puppies. The diagnosis was confirmed on histopathology in one patient. CONCLUSION: MO is considered a disease of large and giant-breed dogs, being rarely reported in non-large-breed dogs, and has not been reported in the Australian Kelpie, which is considered a medium-breed dog. This case series suggests a previously unreported breed predisposition to MO in the Australian Kelpie.

A novel loss-of-function mutation in Npr2 clarifies primary role in female reproduction and reveals a potential therapy for acromesomelic dysplasia, Maroteaux type.

We discovered a new spontaneous mutant allele of Npr2 named peewee (pwe) that exhibits severe disproportionate dwarfism and female infertility. The pwe phenotype is caused by a four base-pair deletion in exon 3 that generates a premature stop codon at codon 313 (L313X). The Npr2(pwe/pwe) mouse is a model for the human skeletal dysplasia acromesomelic dysplasia, Maroteaux type (AMDM). We conducted a thorough analysis of the female reproductive tract and report that the primary cause of Npr2(pwe/pwe) female infertility is premature oocyte meiotic resumption, while the pituitary and uterus appear to be normal. Npr2 is expressed in chondrocytes and osteoblasts. We determined that the loss of Npr2 causes a reduction in the hypertrophic and proliferative zones of the growth plate, but mineralization of skeletal elements is normal. Mutant tibiae have increased levels of the activated form of ERK1/2, consistent with the idea that natriuretic peptide receptor type 2 (NPR2) signaling inhibits the activation of the MEK/ERK mitogen activated protein kinase pathway. Treatment of fetal tibiae explants with mitogen activated protein kinase 1 and 2 inhibitors U0126 and PD325901 rescues the Npr2(pwe/pwe) growth defect, providing a promising foundation for skeletal dysplasia therapeutics.

Hypertrophic osteodystrophy preceding canine juvenile cellulitis in an Australian shepherd puppy.

A 10-week-old intact female Australian shepherd dog was presented sternally recumbent, mildly pyrexic, and painful on long bone palpation of both forelimbs. Based on radiographs she was diagnosed with hypertrophic osteodystrophy. Analgesia was provided with intravenous, oral, and topical medications. Approximately 2 wk later she was presented for facial swelling, regional dermatitis, and lymphadenopathy. Canine juvenile cellulitis was diagnosed and successfully treated.

Craniometaphyseal dysplasia unnoticed until 19 years of age: First diagnosed from facial nerve paralysis.

Craniometaphyseal dysplasia (CMD) is a rare congenital bone disorder with facial dysmorphism developing from early childhood. We describe an unusual case of CMD unnoticed until the patient was 19 years old. Her disorder was diagnosed for the first time from her facial nerve paralysis, and was treated with high-dose corticosteroids. This report indicates the need for extreme caution in dealing with facial nerve paralysis since early detection and accurate diagnosis is important in the treatment of bone diseases. High-dose corticosteroid could be effective in treating facial nerve paralysis, even when nerves have been directly constricted by a bony overgrowth.