Effects of odanacatib on bone-turnover markers in osteoporotic postmenopausal women: a post hoc analysis of the LOFT study.

This post hoc analysis and modeling study examined the mechanism of action of odanacatib using a statistical model to explain sCTx response in ODN-treated patients as a function of other bone-turnover biomarkers that, with other observed biomarker changes, showed that odanacatib persistently inhibited osteoclastic bone removal activity without preventing osteoclastogenesis. INTRODUCTION: Odanacatib (ODN) is an oral selective cathepsin K (CatK) inhibitor, previously in development for osteoporosis treatment. A post hoc analysis examined ODN's mechanism of action on bone-turnover biomarkers. METHODS: A subset of patients who completed 60 months' treatment in the Long-Term Odanacatib Fracture Trial (LOFT; NCT00529373) (N = 112 [57 ODN, 55 placebo]) were evaluated. Serum (s) and urine (u) samples were assayed at baseline and months 6-60 for 10 known bone-remodeling biomarkers: sCTx, uαα- and ußßCTx/Cr, uNTx/Cr, sNTx, uDPD/Cr, sICTP, sTRAP5b, sPINP, and sBSAP. Because the CrossLaps® CTx assay identifies the CTx peptide as well as larger molecular weight CTx-containing peptides, including ICTP, a best-fit model was developed to explain the transient sCTx reduction in ODN-treated patients. RESULTS: ODN persistently reduced the bone-resorption markers sNTx, uNTx/Cr, uαα- and ußßCTx/Cr, and uDPD/Cr, and gradually increased the target-engagement marker sICTP and osteoclast number (sTRAP5b), versus placebo from baseline to month 60. sCTx was transiently reduced with ODN within 12 months, returning to baseline by month 48. Modeling suggested that sCTx changes in the ODN group were primarily due to increased accumulation of larger CTx species, including sICTP. The bone-formation markers sPINP and sBSAP showed partial reductions, versus placebo, in the first 6 months but approached baseline by months 48-60. CONCLUSION: Observed changes in bone-turnover biomarkers support the persistent efficacy of ODN in direct inhibition of osteoclastic bone-resorption activity, without inhibition of osteoclastogenesis. Long-term evaluation also underscores the unique mechanism of ODN on osteoclastic collagen processing and subsequently osteoblastic bone formation. TRIAL REGISTRATION: NCT00529373.

Creating work environments where people of all genders in gynecologic oncology can thrive: An SGO evidence-based review.

Equality, equity, and parity in the workplace are necessary to optimize patient care across all aspects of medicine. Gender-based inequities remain an obstacle to quality of care, including within the now majority women subspecialty of gynecologic oncology. The results of the 2020 SGO State of the Society Survey prompted this evidence-based review. Evidence related to relevant aspects of the clinical care model by which women with malignancies are cared for is summarized. Recommendations are made that include ways to create work environments where all members of a gynecologic oncology clinical care team, regardless of gender, can thrive. These recommendations aim to improve equality and equity within the specialty and, in doing so, elevate the care that our patients receive.

Intraperitoneal chemotherapy following neoadjuvant chemotherapy and optimal interval tumor reductive surgery for advanced ovarian cancer.

OBJECTIVES: Intraperitoneal (IP) chemotherapy following neoadjuvant chemotherapy (NACT) and interval tumor reductive surgery (TRS) for advanced ovarian cancer is feasible, however, the impact on disease outcomes remains unclear. We compare outcomes of patients treated with IP chemotherapy versus intravenous (IV) chemotherapy following NACT and interval TRS. METHODS: In this retrospective review, patients with advanced ovarian cancer were included if they received NACT followed by optimal interval TRS between 1/2004 and 4/2017. Patients were excluded if they had an ECOG PS >1, received >6 cycles of NACT or postoperative chemotherapy, and/or received bevacizumab during primary therapy. Primary outcomes were progression free survival (PFS) and overall survival (OS). RESULTS: There were 134 patients included in this study, 37 (28%) received IP and 97 (72%) received IV chemotherapy postoperatively. Patients in the IV group were older (median 66.3 vs 59.7 years, p = 0.0039) though there were no differences in BMI, race, BRCA status, stage, or histology. Median PFS was 3 months longer in the IP group (14.5 versus 11.5 months, p = 0.028) however there was no significant difference in OS. On univariate analysis, increasing number of NACT cycles (HR 1.914, 95% CI 1.024-3.497) and residual disease at completion of TRS (HR 1.541, 95% CI 1.042-2.248) were associated with decreased PFS; IP chemotherapy was associated with increased PFS (HR 0.633, 95% CI 0.414-0.944). These associations remained on multivariate analysis. Toxicity was comparable between the groups. CONCLUSIONS: IP after NACT and optimal interval TRS was associated with in improved PFS compared to IV chemotherapy without significant differences in toxicity.

Endometrial carcinoma recurrence according to race and ethnicity: An NRG Oncology/Gynecologic Oncology Group 210 Study.

Non-Hispanic black (NHB) women are more likely to experience an endometrial carcinoma (EC) recurrence compared to non-Hispanic white (NHW) women. The extent to which tumor characteristics, socioeconomic status (SES) and treatment contribute to this observation is not well defined. In the NRG Oncology/Gynecology Oncology Group (GOG) 210 Study we evaluated associations between race/ethnicity and EC recurrence according to tumor characteristics with adjustment for potential confounders. Our analysis included 3,199 NHW, 532 NHB and 232 Hispanic women with EC. Recurrence was documented during follow-up. We used Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between race/ethnicity and EC recurrence in models stratified by histologic subtype (low-grade endometrioid, high-grade endometrioid, serous, mixed cell, carcinosarcoma, clear cell) or stage (I, II, III) and adjusted for age, SES, body mass index, smoking status and treatment. In histologic subtype-stratified models, higher EC recurrence was noted in NHB women with low-grade endometrioid (HR = 1.94, 95% CI = 1.21-3.10) or carcinosarcomas (HR = 1.66, 95% CI = 0.99-2.79) compared to NHWs. In stage-stratified models, higher EC recurrence was noted among NHB women with stage I (HR = 1.48, 95% CI = 1.06-2.05) and Hispanic women with stage III disease (HR = 1.81, 95% CI = 1.11-2.95). Our observations of higher EC recurrence risk among NHB and Hispanic women, as compared to NHW women, were not explained by tumor characteristics, SES, treatment or other confounders. Other factors, such as racial differences in tumor biology or other patient factors, should be explored as contributors to racial disparities in EC recurrence.

A phase I trial of paclitaxel, cisplatin, and veliparib in the treatment of persistent or recurrent carcinoma of the cervix: an NRG Oncology Study (NCT#01281852).

Background: Preclinical studies demonstrate poly(ADP-ribose) polymerase (PARP) inhibition augments apoptotic response and sensitizes cervical cancer cells to the effects of cisplatin. Given the use of cisplatin and paclitaxel as first-line treatment for persistent or recurrent cervical cancer, we aimed to estimate the maximum tolerated dose (MTD) of the PARP inhibitor veliparib when added to chemotherapy. Patients and methods: Women with persistent or recurrent cervical carcinoma not amenable to curative therapy were enrolled. Patients had to have received concurrent chemotherapy and radiation as well as possible consolidation chemotherapy; have adequate organ function. The trial utilized a standard 3 + 3 phase I dose escalation with patients receiving paclitaxel 175 mg/m2 on day 1, cisplatin 50 mg/m2 on day 2, and escalating doses of veliparib ranging from 50 to 400 mg orally two times daily on days 1-7. Cycles occurred every 21 days until progression. Dose-limiting toxicities (DLTs) were assessed at first cycle. Fanconi anemia complementation group D2 (FANCD2) foci was evaluated in tissue specimens as a biomarker of response. Results: Thirty-four patients received treatment. DLTs (n = 1) were a grade 4 dyspnea, a grade 3 neutropenia lasting ≥3 weeks, and febrile neutropenia. At 400 mg dose level (DL), one of the six patients had a DLT, so the MTD was not reached. Across DLs, the objective response rate (RR) for 29 patients with measurable disease was 34% [95% confidence interval (CI), 20%-53%]; at 400 mg DL, the RR was 60% (n = 3/5; 95% CI, 23%-88%). Median progression-free survival was 6.2 months (95% CI, 2.9-10.1), and overall survival was 14.5 months (95% CI, 8.2-19.4). FANCD2 foci was negative or heterogeneous in 31% of patients and present in 69%. Objective RR were not associated with FANCD2 foci (P = 0.53). Conclusions: Combining veliparib with paclitaxel and cisplatin as first-line treatment for persistent or recurrent cervical cancer patients is safe and feasible. Clinical trial information: NCT01281852.

Mutations in DYNC2H1, the cytoplasmic dynein 2, heavy chain 1 motor protein gene, cause short-rib polydactyly type I, Saldino-Noonan type.

The short-rib polydactyly syndromes (SRPS) are autosomal recessively inherited, genetically heterogeneous skeletal ciliopathies. SRPS phenotypes were historically categorized as types I-IV, with type I first delineated by Saldino and Noonan in 1972. Characteristic findings among all forms of SRP include short horizontal ribs, short limbs and polydactyly. The SRP type I phenotype is characterized by a very small thorax, extreme micromelia, very short, poorly mineralized long bones, and multiple organ system anomalies. To date, the molecular basis of this most severe type of SRP, also known as Saldino-Noonan syndrome, has not been determined. We identified three SRP cases that fit the original phenotypic description of SRP type I. In all three cases, exome sequence analysis revealed compound heterozygosity for mutations in DYNC2H1, which encodes the main component of the retrograde IFT A motor, cytoplasmic dynein 2 heavy chain 1. Thus SRP type I, II, III and asphyxiating thoracic dystrophy (ATD), which also result from DYNC2H1 mutations. Herein we describe the phenotypic features, radiographic findings, and molecular basis of SRP type I.

A personalized paradigm in the treatment of platinum-resistant ovarian cancer - A cost utility analysis of genomic-based versus cytotoxic therapy.

OBJECTIVE: To assess the cost-effectiveness of a strategy employing genomic-based tumor testing to guide therapy for platinum-resistant ovarian cancer. METHODS: A decision model was created to compare standard of care (SOC) cytotoxic chemotherapy to a genomic-based treatment strategy. The genomic arm included tumor testing with treatment directed at targets identified. Overall survival was assumed to be similar between strategies; quality of life (QOL) was assumed superior during targeted therapy compared to chemotherapy. Pertinent uncertainties (cost of targeted therapy and genomic testing, response to targeted therapy, probability of a tumor having a targetable alteration, and impact on QOL) were evaluated in a series of one-and two-way sensitivity analyses. RESULTS: The genomic testing strategy was more expensive ($90,271 vs. $74,926) per patient than SOC. The incremental cost-effectiveness ratio (ICER) of the genomic strategy was $479,303 per quality-adjusted life year saved (QALY). Model results were insensitive to the cost of genomic testing, differences in QOL, and the probability of identifying a targetable alteration. However, the model was sensitive to the cost of targeted therapy. For example, when the cost of targeted therapy was reduced to 56% of its current cost (or $6400/cycle), the genomic strategy became more cost-effective with an ICER of $96,612/QALY. CONCLUSIONS: Genomic-based tumor testing and targeted therapy in patients with platinum-resistant ovarian cancer is not cost-effective compared with SOC. However, reducing the cost of targeted therapy (independently, or in combination with reducing the cost of the genomic test) provides opportunities for improved value in cancer care.

The mutational spectrum of FOXA2 in endometrioid endometrial cancer points to a tumor suppressor role.

BACKGROUND: Forkhead box protein A2 (FOXA2) plays an important in development, cellular metabolism and tumorigenesis. The Cancer Genome Atlas (TCGA) identified a modest frequency of FOXA2 mutations in endometrioid endometrial cancers (EEC). The current study sought to determine the relationship between FOXA2 mutation and clinicopathologic features in EEC and FOXA2 expression. METHODS: Polymerase chain reaction (PCR) amplification and sequencing were used to identify mutations in 542 EEC. Western blot, quantitative reverse transcriptase PCR (qRT-PCR) and immunohistochemistry (IHC) were used to assess expression. Methylation analysis was performed using combined bisulfite restriction analysis (COBRA) and sequencing. Chi-squared, Fisher's exact, Student's t- and log-rank tests were performed. RESULTS: Fifty-one mutations were identified in 49 tumors (9.4% mutation rate). The majority of mutations were novel, loss of function (LOF) (78.4%) mutations, and most disrupted the DNA-binding domain (58.8%). Six recurrent mutations were identified. Only two tumors had two mutations and there was no evidence for FOXA2 allelic loss. Mutation status was associated with tumor grade and not associated with survival outcomes. Methylation of the FOXA2 promoter region was highly variable. Most tumors expressed FOXA2 at both the mRNA and protein level. In those tumors with mutations, the majority of cases expressed both alleles. CONCLUSION: FOXA2 is frequently mutated in EEC. The pattern of FOXA2 mutations and expression in tumors suggests complex regulation and a haploinsufficient or dominant-negative tumor suppressor function. In vitro studies may shed light on how mutations in FOXA2 affect FOXA2 pioneer and/or transcription factor functions in EEC.

Next-generation sequencing for disorders of low and high bone mineral density.

UNLABELLED: To achieve an efficient molecular diagnosis of osteogenesis imperfecta (OI), Ehlers-Danlos syndrome (EDS), and osteopetrosis (OPT), we designed a next-generation sequencing (NGS) platform to sequence 34 genes. We validated this platform on known cases and have successfully identified the causative mutation in most patients without a prior molecular diagnosis. INTRODUCTION: Osteogenesis imperfecta, Ehlers-Danlos syndrome, and osteopetrosis are collectively common inherited skeletal diseases. Evaluation of subjects with these conditions often includes molecular testing which has important counseling and therapeutic and sometimes legal implications. Since several different genes have been implicated in these conditions, Sanger sequencing of each gene can be a prohibitively expensive and time-consuming way to reach a molecular diagnosis. METHODS: In order to circumvent these problems, we have designed and tested a NGS platform that would allow simultaneous sequencing on a single diagnostic platform of different genes implicated in OI, OPT, EDS, and other inherited conditions, leading to low or high bone mineral density. We used a liquid-phase probe library that captures 602 exons (~100 kb) of 34 selected genes and have applied it to test clinical samples from patients with bone disorders. RESULTS: NGS of the captured exons by Illumina HiSeq 2000 resulted in an average coverage of over 900X. The platform was successfully validated by identifying mutations in six patients with known mutations. Moreover, in four patients with OI or OPT without a prior molecular diagnosis, the assay was able to detect the causative mutations. CONCLUSIONS: In conclusion, our NGS panel provides a fast and accurate method to arrive at a molecular diagnosis in most patients with inherited high or low bone mineral density disorders.

Is selective lymphadenectomy more cost-effective than routine lymphadenectomy in patients with endometrial cancer?

OBJECTIVE: The objective of this study is to determine the cost-effectiveness of two strategies in women undergoing surgery for newly diagnosed endometrial cancer. METHODS: A decision analysis model compared two surgical strategies: 1) routine lymphadenectomy independent of intraoperative risk factors or 2) selective lymphadenectomy for women with high or intermediate risk tumors based on intraoperative assessment including tumor grade, depth of invasion, and tumor size. Published data were used to estimate the outcomes of stage, adjuvant therapy, and recurrence. Costs of surgery, radiation, and chemotherapy were estimated using Medicare Current Procedural Technology codes and Physician Fee Schedule. Cost-effectiveness ratios were estimated for each strategy. Sensitivity analyses were performed including an estimate for lymphedema for patients that underwent a lymphadenectomy. RESULTS: For 40,000 women diagnosed annually with endometrial cancer in the United States, the annual cost of selective lymphadenectomy is $1.14 billion compared to $1.02 billion for routine lymphadenectomy. The selective lymphadenectomy strategy cost an additional $123.3 million. Five-year progression-free survival was 85.9% in the routine strategy compared to 79.3% in the selective strategy. Treatment cost $6349 more per survivor in the selective strategy compared to routine strategy ($36,078 vs. $29,729). These results held up under a variety of sensitivity analyses including costs due to lymphedema which were higher in the routine lymphadenectomy strategy compared to the selective lymphadenectomy strategy ($10 million vs. $7.75 million). CONCLUSIONS: A strategy of selective lymphadenectomy based on intraoperative risk factors for patients with endometrial cancer was less cost-effective than routine lymphadenectomy even when the impact of lymphedema was considered.

Is the progression free survival advantage of concurrent gemcitabine plus cisplatin and radiation followed by adjuvant gemcitabine and cisplatin in patients with advanced cervical cancer worth the additional cost? A cost-effectiveness analysis.

OBJECTIVE: The objective of this study is to determine whether concurrent and adjuvant chemoradiation with gemcitabine/cisplatin is cost-effective in patients with stage IIB to IVA cervical cancer. METHODS: A cost-effectiveness model compared two arms of the trial performed by Duenas-Gonzalez et al. [1]: concurrent and adjuvant chemoradiation with gemcitabine/cisplatin (RT/GC+GC) versus concurrent radiation with cisplatin (RT/C). Major adverse events (AEs) and progression free survival (PFS) rates of each arm were incorporated in the model. AEs were defined as any hospitalization including grade 4 anemia, grade 4 neutropenia, and death. Medicare data and literature review were used to estimate costs. Incremental cost-effectiveness ratios (ICERs) per progression-free life-year saved (PF-LYS) were calculated. Sensitivity analyses were performed for pertinent uncertainties. RESULTS: For 10,000 women with locally advanced cervical cancer, the cost of therapy and AEs was $173.9 million (M) for RT/C versus $259.8M for RT/GC+GC. There were 879 additional 3-year progression-free survivors in the RT/GC+GC arm. The ICER for RT/GC+GC was $97,799 per PF-LYS. When the rate of hospitalization was equalized to 4.3%, the ICER for RT/GC+GC exceeded $80,000. The resultant ICER when increasing PFS in the RT/GC+GC arm by 5% was $62,605 per PF-LYS. When the cost of chemotherapy was decreased by 50%, the ICER was below $50,000 at $41,774 per PF-LYS. CONCLUSIONS: Radiation and gemcitabine/cisplatin for patients with stage IIB to IVA cervical cancer are not cost-effective. The increased financial burden of radiation with gemcitabine/cisplatin and associated toxicities appears to outweigh the benefit of increased 3-year PFS and is primarily dependent on chemotherapy drug costs.

Outcomes following percutaneous upper gastrointestinal decompressive tube placement for malignant bowel obstruction in ovarian cancer.

OBJECTIVE: The objective of this study was to evaluate peri-operative and survival outcomes of ovarian cancer patients undergoing percutaneous upper gastrointestinal decompression for malignant bowel obstruction (MBO). METHODS: Retrospective chart review was used to identify patients with ovarian, peritoneal, or fallopian tube cancer who underwent palliative decompressive treatment for MBO from 1/2002 to 12/2010. Kaplan-Meier methods were used to estimate the median survival (MS) and multivariate analysis used to determine if any variables were associated with the hazard of death. RESULTS: Fifty-three patients met inclusion criteria. Median length of diagnosis prior to intervention was 21 months. Fifteen (28.3%) patients experienced complications and 9 required revision. Forty-nine (92.5%) experienced relief of symptoms after placement, and 91% tolerated some form of oral intake. Following placement, 19 (36%) patients received additional chemotherapy and 21(41%) patients received total parental nutrition (TPN). Thirty-five patients were discharged home/outpatient facility, 16 to hospice care, and 2 died prior to discharge. MS for all patients was 46 days. Patients who received chemotherapy had a MS of 169 days compared to 33 days (p<0.001). We failed to find an association between survival and TPN or performance status. CONCLUSIONS: Malignant bowel obstruction is a common complication of ovarian cancer. Management is palliative; risks and benefits of any therapy must be considered. Percutaneous decompressive therapy provides relief from associated symptoms, and allows patients to be discharged home. Median survival in this group is limited, and decisions regarding aggressive therapy should be individualized.

Dominant mutations in the type II collagen gene, COL2A1, produce spondyloepimetaphyseal dysplasia, Strudwick type.

The chondrodysplasias are a heterogeneous group of disorders characterized by abnormal growth or development of cartilage. Current classification is based on mode of inheritance as well as clinical, histologic, and/or radiographic features. A clinical spectrum of chondrodysplasia phenotypes, ranging from mild to perinatal lethal, is due to defects in the gene for type II collagen, COL2A1. This spectrum includes Stickler syndrome, Kniest dysplasia, spondyloepiphyseal dysplasia congenita (SEDC), achondrogenesis type II, and hypochondrogenesis. Individuals affected with these disorders exhibit abnormalities of the growth plate, nucleus pulposus, and vitreous humor, which are tissues that contain type II collagen. The Strudwick type of spondyloepimetaphyseal dysplasia (SEMD) is characterized by disproportionate short stature, pectus carinatum, and scoliosis, as well as dappled metaphyses (which are not seen in SEDC). The phenotype was first described by Murdoch and Walker in 1969, and a series of 14 patients was later reported by Anderson et al. The observation of two affected sibs born to unaffected parents led to the classification of SEMD Strudwick as an autosomal recessive disorder. We now describe the biochemical characterization of defects in alpha 1(II) collagen in three unrelated individuals with SEMD Strudwick, each of which is due to heterozygosity for a unique mutation in COL2A1. Our data support the hypothesis that some cases, if not all cases, of this distinctive chondrodysplasia result from dominant mutations in COL2A1, thus expanding the clinical spectrum of phenotypes associated with this gene.

A type X collagen mutation causes Schmid metaphyseal chondrodysplasia.

The expression of type X collagen is restricted to hypertrophic chondrocytes in regions undergoing endochondral ossification, such as growth plates. The precise function of type X collagen is unknown but the tissue-specific expression prompted us to examine the gene in hereditary disorders of cartilage and bone growth (osteochondrodysplasias). We have identified a 13 base pair deletion in one type X collagen allele segregating with autosomal dominant Schmid metaphyseal chondrodysplasia in a large Mormon kindred (lod score = 18.2 at theta = 0). The mutation produces a frameshift which alters the highly conserved C-terminal domain of the alpha 1(X) chain and reduces the length of the polypeptide by nine residues. This mutation may prevent association of the mutant polypeptide during trimer formation, resulting in a decreased amount of normal protein.

Mutations in orthologous genes in human spondyloepimetaphyseal dysplasia and the brachymorphic mouse.

The osteochondrodysplasias are a genetically heterogeneous group of disorders affecting skeletal development, linear growth and the maintenance of cartilage and bone. We have studied a large inbred Pakistani family with a distinct form of recessively inherited spondyloepimetaphyseal dysplasia (SEMD) and mapped a gene associated with this dwarfing condition to chromosome 10q23-24, a region syntenic with the locus for the brachymorphic mutation on mouse chromosome 19. We identified two orthologous genes, ATPSK2 and Atpsk2, encoding novel ATP sulfurylase/APS kinase orthologues in the respective regions of the human and mouse genomes. We characterized a nonsense mutation in ATPSK2 in the SEMD family and a missense mutation in the region of Atpsk2 encoding the APS kinase activity in the brachymorphic mouse. ATP sulfurylase/APS kinase catalyses the metabolic activation of inorganic sulfate to PAPS, the universal donor for post-translational protein sulfation in all cell types. The cartilage-specificity of the human and mouse phenotypes provides further evidence of the critical role of sulfate activation in the maturation of cartilage extracellular matrix molecules and the effect of defects in this process on the architecture of cartilage and skeletogenesis.

Thanatophoric dysplasia (types I and II) caused by distinct mutations in fibroblast growth factor receptor 3.

Thanatophoric dysplasia (TD), the most common neonatal lethal skeletal dysplasia, affects one out of 20,000 live births. Affected individuals display features similar to those seen in homozygous achondroplasia. Mutations causing achondroplasia are in FGFR3, suggesting that mutations in this gene may cause TD. A sporadic mutation causing a Lys650Glu change in the tyrosine kinase domain of FGFR3 was found in 16 of 16 individuals with one type of TD. Of 39 individuals with a second type of TD, 22 had a mutation causing an Arg248Cys change and one had a Ser371Cys substitution, both in the extracellular region of the protein. None of these mutations were found in 50 controls showing that mutations affecting different functional domains of FGFR3 cause different forms of this lethal disorder.

Heterozygous mutations in the gene encoding noggin affect human joint morphogenesis.

The secreted polypeptide noggin (encoded by the Nog gene) binds and inactivates members of the transforming growth factor beta superfamily of signalling proteins (TGFbeta-FMs), such as BMP4 (ref. 1). By diffusing through extracellular matrices more efficiently than TGFbeta-FMs, noggin may have a principal role in creating morphogenic gradients. During mouse embryogenesis, Nog is expressed at multiple sites, including developing bones. Nog-/- mice die at birth from multiple defects that include bony fusion of the appendicular skeleton. We have identified five dominant human NOG mutations in unrelated families segregating proximal symphalangism (SYM1; OMIM 185800) and a de novo mutation in a patient with unaffected parents. We also found a dominant NOG mutation in a family segregating multiple synostoses syndrome (SYNS1; OMIM 186500); both SYM1 and SYNS1 have multiple joint fusion as their principal feature. All seven NOG mutations alter evolutionarily conserved amino acid residues. The findings reported here confirm that NOG is essential for joint formation and suggest that NOG requirements during skeletogenesis differ between species and between specific skeletal elements within species.