Assessing tuberculosis in the skeleton with the use of decision tree analysis

Diagnosis of specific infectious diseases in the skeleton is often difficult and relies on expert opinion. Statistics is not often used as a tool to assist in such diagnoses, and therefore this study aimed at employing data mining and machine learning in the form of decision tree analysis to aid in recognizing tuberculosis (TB) in skeletal remains and find patterns of skeletal involvement. The sample included 387 modern South African individuals (n = 207 individuals known to have died of TB and n = 180 as a control group) which were scored for the presence or absence of 21 skeletal lesions documented to be associated with TB. A pruned decision tree classification analysis was done to detect significant patterns and associations between variables which produced a model with a moderate classification rate based on four of the variables. As expected, vertebral changes were selected first, followed by rib, acetabular and lastly cranial changes. As a proof of concept, it was shown that machine learning was able to identify patterns of changes in TB skeletons versus a control group. However, further investigation into the use of machine learning in assessing skeletal changes associated with specific diseases is needed.

Design, synthesis and biological evaluation of novel DCLK1 inhibitor containing purine skeleton for the treatment of pancreatic cancer

Pancreatic cancer is a highly lethal form of malignancy that continues to pose a significant and unresolved health challenge. Doublecortin-like kinase 1 (DCLK1), a serine/threonine kinase, is found to be overexpressed in pancreatic cancer and holds promise as a potential therapeutic target for this disease. However, few potent inhibitors have been reported currently. Herein, a series of novel purine, pyrrolo [2,3-d]pyrimidine, and pyrazolo [3,4-d] pyrimidine derivatives were designed, synthesized, and evaluated their biological activities in vitro. Among them, compound I-5 stood out as the most potent compound with strong inhibitory activity against DCLK1 (IC50 = 171.3 nM) and remarkable antiproliferative effects on SW1990 cell lines (IC50 = 0.6 μM). Notably, I-5 exhibited higher in vivo antitumor potency (Tumor growth inhibition value (TGI): 68.6 %) than DCLK1-IN-1 (TGI: 24.82 %) in the SW1990 xenograft model. The preliminary mechanism study demonstrated that I-5 not only inhibited SW1990 cell invasion and migration, but also decreased the expression of prominin-1 (CD133) and cluster of differentiation 44 (CD44), which are considered as differentiation markers for SW1990 stem cells. All the results indicated that I-5, a novel DCLK1 inhibitor, shows promise for further investigation in the treatment of pancreatic cancer.

Case Report: A Giant Epignathus with a Well-Developed Skeleton of Head and Neck

Epignathus is an extremely rare teratoma found in the oral cavity or oropharyngeal region of newborns, whose pathogenesis is poorly understood. We describe a giant epignathus arising from the oropharynx in a newborn. The giant tumor completely obstructed the airway of the newborn resulting in death. Histological and radiological examination of the tumor reveals the presence of a remarkably well-developed skeleton of the head and neck. A row of teeth, the axis and atlas, thyroid and salivary glands, trachea, and cerebral tissue are all detected within the tumor. These findings suggest that the epignathus is fetus-in-fetu which is considered a type 0 germ cell tumor in accordance with current literature.

The association between skeletal lesions and tuberculosis in a pre-antibiotic South African sample

OBJECTIVE

This study assessed the sensitivity and specificity of skeletal lesions to accurately diagnose TB in a pre-antibiotic South African skeletal sample.

MATERIALS

A total of 435 skeletons of individuals who died before 1950 from the Raymond A. Dart Collection of Human Skeletons. 176 died of TB, 109 died of other pulmonary diseases, and 150 died of other causes.

METHODS

The presence / absence of 23 skeletal lesions were assessed for differences in frequency between groups. Sensitivities and specificities were calculated and compared to Dangvard Pedersen et al. (2019).

RESULTS

Lesions on the ventral surface of thoracic and lumbar vertebral bodies were observed significantly more often in TB and pulmonary cases than in other cause of death group and yielded a 55% probability of a true TB diagnosis, if observed. An association between skeletal lesions and TB was found for rib and vertebral lesions.

CONCLUSIONS

The results suggest that even when not documented to have died of TB, TB-related changes are observed in many individuals in a South African skeletal sample, indicating that they may have been infected with the disease.

SIGNIFICANCE

The study provides information that can assist palaeopathologists in making inferences about the prevalence of TB in past populations.

LIMITATIONS

Sample sizes were small, and the inclusion of a pulmonary disease group may have confounded the results.

SUGGESTIONS FOR FURTHER RESEARCH

The selection of a control group without any possible contact with TB may improve the results and should be investigated.

A rare femoral heterotopic bone formation in a 14th-19th century female skeleton from Constância (Portugal)

OBJECTIVE

This paper aims to: (1) document a rare femoral heterotopic ossification (HO), and (2) discuss its aetiology and impact on the individual's locomotion and daily living activities.

MATERIALS

Adult female skeleton (SG.14-SK.7) from the village of Constância (Portugal), and dated from the 14th-19th centuries CE.

METHODS

The biological profile and the macroscopic analysis of the bone changes were assessed using standardized methods.

RESULTS

The macroscopic analysis revealed a large bony mass (8 cm length) located immediately inferior to the small trochanter of the right femur. The lesion exhibited a compact, tubular appearance located at the site of attachment of the pectineus muscle. No signs of bone fracture were observed.

CONCLUSIONS

The morphology of the SG.14-SK.7 femoral lesion is compatible with a probable case of myositis ossificans traumatica (MOT), secondary to acute trauma of the pectineus muscle. The underlying trauma episode, such as random accidental and/or occupation-related injury, is unknown. However, it is highly possible that this self-limiting condition significantly impaired the individual's daily life and mobility.

SIGNIFICANCE

Evidence of severe acute muscle trauma is a rare finding compared with HO secondary to bone trauma and other minor muscle injuries. Moreover, no cases of MOT affecting the pectineus muscle have been reported in the paleopathological literature to date.

LIMITATIONS

Although unlikely, a case of neurogenic or burn-related HO cannot be completely disregarded. It was not possible to undertake radiography as part of this study.

SUGGESTIONS FOR FURTHER RESEARCH

The use of imaging techniques to complement the paleopathological description is advised.

Correlation between Whole Skeleton Dual Energy CT Calcium-Subtracted Attenuation and Bone Marrow Infiltration in Multiple Myeloma

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Quantification of whole skeleton calcium-subtracted attenuation with dual energy CT is feasible.

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Whole skeleton calcium-subtracted attenuation correlates with the degree of marrow infiltration by plasma cells on bone marrow biopsy.

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Whole skeleton calcium-subtracted attenuation provides complementary information to the detection of osteolytic bone lesions.

Objectives

Objective evaluation of the extent of skeletal marrow involvement in multiple myeloma remains a clinical gap for CT. We aimed to develop a quantitative segmentation pipeline for dual energy CT and to assess whether quantified whole skeleton calcium-subtracted attenuation values correlate with biopsy-derived bone marrow infiltration in multiple myeloma.

Methods

Consecutive prospective patients with suspected/established myeloma underwent dual source CT from the skull vertex to proximal tibia. Whole skeleton segmentation was performed for 120 kVp-equivalent images as follows: following Hounsfield unit (HU) thresholding, a Chan-Vese morphological operation was implemented to generate a whole skeleton segmentation mask. This mask was then applied to corresponding whole skeleton material decomposition calcium-subtracted maps, generating whole skeleton HU values. Associations with biopsy-derived bone marrow plasma cell infiltration percentage were assessed with Spearman’s rank correlation; significance was at 5%.

Results

21 patients (12 females; median (IQR) 67 (61, 73) years) were included; 16 patients had osteolytic bone lesions; 15 patients underwent bone marrow biopsy. Segmentation and quantification were feasible in all patients. Median (IQR) of the average skeletal calcium-subtracted attenuation was −59.9 HU (-66.3, −51.8HU). There was a positive correlation with bone marrow plasma cell infiltration percentage (Spearman’s rho: + 0.79, p < 0.001).

Conclusion

Whole skeleton calcium-subtracted attenuation is associated with the degree of bone marrow infiltration by plasma cells, providing an objective measure of marrow involvement with the potential to allow earlier detection of disease.

Clinical, radiological and computational studies on two novel GNPTG variants causing mucolipidosis III gamma phenotypes with varying severity

Mucolipidosis III gamma (ML III γ) is a slowly progressive disorder that affects multiple parts of the body such as the skeleton, joints, and connective tissue structures. It is caused by pathogenic variants in the GNPTG gene that provides instructions for producing the γ subunit of GlcNAc-1-phosphotransferase. In this study we aim to characterize clinical findings and biological insights on two novel GNPTG variants causing ML III γ phenotypes with varying severity. We report on two siblings with ML III γ bearing the previously undescribed c.477C > G (p.Y159*) nonsense variant in a homozygous state as well as a patient with ML III γ bearing the novel c.110 + 19_111-17del variant in a homozygous state. These variants were revealed by whole-exome sequencing and Sanger sequencing, respectively. Their parents, who are heterozygotes for the same mutation, are healthy. The clinical and radiographic presentation of ML III γ in our patients who had c.477C > G (p.Y159*) variant is consistent with a relatively severe form of the disease, which is further supported by a working three-dimensional model of the GlcNAc-1-phosphotransferase γ subunit. On the other hand, it is seen that our patient who carries the c.110 + 19_111-17del variant has a milder phenotype. Our findings help broaden the spectrum of GNPTG variants causing ML III γ and offer structural and mechanistic insights into loss of GlcNAc-1-phosphotransferase γ subunit function.

Tracking down the White Plague. Chapter two: The role of endocranial abnormal blood vessel impressions and periosteal appositions in the paleopathological diagnosis of tuberculous meningitis

Although endocranial abnormal blood vessel impressions (ABVIs) and periosteal appositions (PAs) have been considered as paleopathological diagnostic criteria for tuberculous meningitis (TBM) based on findings of previous studies, they are not pathognomonic for tuberculosis (TB). Therefore, their utilization in the paleopathological practice can be questioned, especially in consideration that most of the previous studies were not performed on identified skeletal collections but on osteoarchaeological material and did not include statistical data analysis. To fill the aforementioned research gap, for the first time, a macroscopic investigation was conducted on identified pre-antibiotic era skeletons from the Terry Collection. A sample set of 234 individuals who died of TB (TB group) and 193 individuals who died of non-tuberculous causes (NTB group) were examined. The frequency of ABVIs and PAs, as well as other probable TB-related lesions was recorded. To determine the significance of difference (if any) in the frequencies of ABVIs and PAs between the two groups, χ² testing of our data was performed. We found that ABVIs, PAs, and their co-occurrence with each other and with other probable TB-related lesions were more common in the TB group than in the NTB group. In addition, the χ² comparative frequencies of ABVIs and PAs revealed a statistically significant difference between individuals who died of TB and individuals who died of NTB causes. Our findings strengthen those of previous studies that ABVIs and PAs are not specific to TBM but can be of tuberculous origin. Therefore, they do have a diagnostic value in the identification of TB in human osteoarchaeological material, especially when they simultaneously occur with other probable TB-related lesions. Their prudent utilization provides paleopathologists with a stronger basis for diagnosing TB and consequently, a more sensitive means of assessing TB frequency in past human populations.

Antxr1, Which is a Target of Runx2, Regulates Chondrocyte Proliferation and Apoptosis

Antxr1/Tem8 is highly expressed in tumor endothelial cells and is a receptor for anthrax toxin. Mutation of Antxr1 causes GAPO syndrome, which is characterized by growth retardation, alopecia, pseudo-anodontia, and optic atrophy. However, the mechanism underlying the growth retardation remains to be clarified. Runx2 is essential for osteoblast differentiation and chondrocyte maturation and regulates chondrocyte proliferation through Ihh induction. In the search of Runx2 target genes in chondrocytes, we found that Antxr1 expression is upregulated by Runx2. Antxr1 was highly expressed in cartilaginous tissues and was directly regulated by Runx2. In skeletal development, the process of endochondral ossification proceeded similarly in wild-type and Antxr1-/- mice. However, the limbs of Antxr1-/- mice were shorter than those of wild-type mice from embryonic day 16.5 due to the reduced chondrocyte proliferation. Chondrocyte-specific Antxr1 transgenic mice exhibited shortened limbs, although the process of endochondral ossification proceeded as in wild-type mice. BrdU-uptake and apoptosis were both increased in chondrocytes, and the apoptosis-high regions were mineralized. These findings indicated that Antxr1, of which the expression is regulated by Runx2, plays an important role in chondrocyte proliferation and that overexpression of Antxr1 causes chondrocyte apoptosis accompanied by matrix mineralization.

A probable case of infantile cortical hyperostosis in 2nd-4th centuries AD Romania

OBJECTIVE

This study aims to discuss the differential diagnosis for the pathological alterations displayed on an infant skeleton from Romania.

MATERIALS

One infant skeleton retrieved form the bathhouse of an abandoned Roman fort and dated between the 2nd and the 4th centuries AD.

METHODS

All available skeletal elements were analyzed macroscopically. In addition, the isotopic signatures (δ13C and δ15N) and the control region of the human mitochondrial genome for this archaeological sample were analyzed.

RESULTS

Based on dental development and long bone length, the skeleton was aged between birth and 2 months of age. Pathological lesions were noted on the mandible and diaphyses of long bones, but spared the metaphyses.

CONCLUSIONS

The perinatal age of the individual, along with lesion morphology and location, suggests a diagnosis of infantile cortical hyperostosis.

LIMITATIONS

The analysis would benefit from further stable isotope and mitochondrial genome analyses, which was limited due to the absence of comparative human and faunal remains from the site.

SUGGESTIONS FOR FURTHER RESEARCH

Further multidisciplinary research on human archaeological remains from Romania would provide a clearer image of past disease and life histories in this geographic area.

Congenital lipodystrophy induces severe osteosclerosis

Berardinelli-Seip congenital generalized lipodystrophy is associated with increased bone mass suggesting that fat tissue regulates the skeleton. Because there is little mechanistic information regarding this issue, we generated "fat-free" (FF) mice completely lacking visible visceral, subcutaneous and brown fat. Due to robust osteoblastic activity, trabecular and cortical bone volume is markedly enhanced in these animals. FF mice, like Berardinelli-Seip patients, are diabetic but normalization of glucose tolerance and significant reduction in circulating insulin fails to alter their skeletal phenotype. Importantly, the skeletal phenotype of FF mice is completely rescued by transplantation of adipocyte precursors or white or brown fat depots, indicating that adipocyte derived products regulate bone mass. Confirming such is the case, transplantation of fat derived from adiponectin and leptin double knockout mice, unlike that obtained from their WT counterparts, fails to normalize FF bone. These observations suggest a paucity of leptin and adiponectin may contribute to the increased bone mass of Berardinelli-Seip patients.

A case of erosive polyarthropathy from Medieval northern Italy (12th-13th centuries)

OBJECTIVE

To evaluate and differentially diagnose erosive skeletal lesions located on multiple joints of an individual archaeologically recovered in 2017.

MATERIALS

Skeletal remains of a well-preserved skeleton dating to the 12th-13th centuries from the medieval church of San Biagio in Cittiglio (Varese, northern Italy).

METHODS

Macroscopic and radiographic imaging.

RESULTS

Erosive marginal symmetrical lesions are present on the metatarsophalangeal, metacarpophalangeal and interphalangeal joints of an adult male, aged 55-75 years. Osteolytic changes, in the form of pocket erosions, surface resorptions and pseudocyst formations, are also macroscopically observed on some carpal and tarsal bones and on several large peripheral joints.

CONCLUSIONS

A careful differential diagnosis of the lesions and their macroscopic and radiological appearance is suggestive of a case of rheumatoid arthritis-like polyarthropathy.

SIGNIFICANCE

This case contributes to the debate regarding the antiquity of erosive polyarthropathies, providing additional evidence for the existence of these diseases in the Old World prior to the European discovery of the Americas.

LIMITATIONS

Small sample size limits discussion of the scope of the disease in antiquity.

SUGGESTIONS FOR FURTHER RESEARCH

This case highlights the need for further macroscopic, radiographic, and biomolecular studies of pre-modern European skeletal samples to investigate the hypothesized pre-existence of these pathological conditions in Europe prior to 1492.

The overlooked primary: bladder cancer metastases on dry bone. A study of the 20th century CAL Milano Cemetery Skeletal Collection

OBJECTIVE

The aim of this article is to provide additional documentation of bone metastases to help anthropologists recognize the condition and potentially suggest the diagnosis of bladder carcinoma in differential diagnosis.

MATERIALS AND METHODS

Thirteen individuals clinically diagnosed with bladder carcinoma from the 20^th century Milano Cemetery Skeletal Collection were macroscopically studied to document bone metastases in bladder cancer.

RESULTS

Bone metastases were found through macroscopic observation in three individuals or 23% of the study sample. Metastases were mostly of a mixed nature (45%), although both osteoblastic (13%) and osteolytic (9%) also occurred. In particular, mixed and osteoblastic metastases exhibited different distribution patterns, even when affecting the same bones. The vertebrae (24.7%), skull (12.9%), ribs (11.7%), proximal humeri (7.8%), pelvis (5.2%), proximal femora (2.6%), sacrum (1.3%) and sternum (1.3%) were the most commonly affected. Osteolytic lesions included coalescing superficial pits or lesions perforating the bone cortex. Proliferative lesions manifested as spongiosclerosis or periosteal new bone. Mixed metastases were osteolytic lesions exposing a thickened trabecular bone or coalescent porosity with reactive new bone.

CONCLUSIONS

Bladder carcinoma metastases were mostly mixed, exhibiting periosteal reactions, perforations of bone cortex, spongiosclerosis and coalescing porosity.

SIGNIFICANCE

Bladder carcinoma is rarely considered in the differential diagnosis of the primary organ. This study reports the macroscopic aspect of bone metastases in bladder carcinoma and may help anthropologists diagnose the condition in skeletons.

LIMITATIONS

Absence of evidence is not evidence of absence; some lesions may have been hidden from macroscopic observation and therefore missed.

FURTHER RESEARCH

Radiographic analysis and comparison with other neoplasms should provide additional details for the diagnosis of bladder cancer bone metastases.

A paleopathological approach to early human adaptation for wet-rice agriculture: The first case of Neolithic spinal tuberculosis at the Yangtze River Delta of China

The earliest evidence of human tuberculosis can be traced to at least the early dynastic periods, when full-scaled wet-rice agriculture began or entered its early developmental stages, in circum-China countries (Japan, Korea, and Thailand). Early studies indicated that the initial spread of tuberculosis coincided with the development of wet-rice agriculture. It has been proposed that the adaptation to agriculture changed human social/living environments, coincidentally favoring survival and spread of pathogenic Mycobacterial strains that cause tuberculosis. Here we present a possible case of spinal tuberculosis evident in the remains of a young female (M191) found among 184 skeletal individuals who were Neolithic wet-rice agriculturalists from the Yangtze River Delta of China, associated with Songze culture (3900-3200 B.C.). This early evidence of tuberculosis in East Asia serves as an example of early human morbidity following the adoption of the wet-rice agriculture.

A critical review of anthropological studies on skeletons from European plague pits of different epochs

In historical times, plague epidemics intermittently ravaged Europe for more than 1,400 years, and still represent a threat in many countries all over the world. A debate is ongoing about the past plague, if it killed randomly in a population or discriminated among persons on the basis of their biological features. To address questions of plague lethality, we reviewed a large number of anthropological studies published in the last twenty years on victims of the past pestilences in Europe. In particular, we focused on data concerning demography (age at death and sex determination), and health status (skeletal biomarkers). We applied to these data a model system based on Multiple Linear Regression, which aimed to discern among possible predictors of sex-selective plague lethality in entire populations, in different periods and regions. Based on available data, we lack evidence for general trends of association between biological features. Differences in sex ratio are more likely due to the original population compositions or to distinct cultural behaviours of the two genders. We concluded that generalizations on biological evidence are not feasible for ancient plagues if we exclude that the infection possibly killed primarily persons between 5-10 and 20-35 years of age.

A probable case of multiple myeloma in a female individual from the Simon Identified Skeletal Collection (late 19th-early 20th century, Vaud, Switzerland)

We present the case of an individual from the Simon Identified Skeletal Collection (Vaud, Switzerland) who appears to have been affected by a form of neoplastic disease. A detailed description and differential diagnosis of the lesions was conducted and is presented here. Considering the biological profile of the individual, the distribution of the lesions, and their appearance, a case is made for multiple myeloma as the most likely diagnosis. This case study demonstrates the importance of adopting a detailed approach for recording the metric and non-metric traits of lesions, using multiple methods of analysis, and providing graphic and photographic documentation in order to provide valuable comparison material through publication. The good preservation of the remains and the background information available for the individual also make this case ideal for inclusion in future comparative studies.

A case of Paget from a Northern Italy medieval necropolis

An excavation conducted in 2002 by the Lombardy Archaeological Heritage in the St. Giulio Church (Cassano Magnago-Northern Italy) revealed an adult skeleton with an important alteration of the left femur. The femur, longer than the contralateral, exhibited an expansion of the full diaphysis; the surface was coarsened and porous. In cross section, it appeared that almost all the cortical bone had been converted into cancellous bone. Macroscopic and radiological alterations are suggestive of the monostotic form of Paget's disease, a chronic disorder, characterized by focal areas of excessive osteoclastic bone resorption followed by a secondary increase in osteoblastic bone formation. Differential diagnosis is complex for Paget's disease, requiring histological analysis, which revealed a thickened and disorganized trabecular pattern with thick cement lines. Such features, resembling to a mosaic pattern, are typical of Paget's disease.

Secondary hypertrophic osteoarthropathy in a male from the Early Medieval settlement of Lauchheim, Germany

Hypertrophic osteoarthropathy (HOA) is rarely diagnosed in archaeological human skeletons. Here, we report on the well-preserved skeleton of a middle-adult man from the early Medieval settlement site of Lauchheim (Germany) that exhibits pronounced multi-layered shell-like periosteal new bone formation in a bilaterally symmetric fashion on the long bones, the skeletal elements of the pelvis and those of the pectoral girdle. In addition, the two distal phalanges recovered show signs of osteoclastic resorption on their distal tuberosities. The distribution and morphology of the observed lesions are consistent with a diagnosis of HOA. The adult age at death of the individual and the co-occurrence of "healed" and "active" lesions suggest a secondary form of HOA. Given that only skeletal remains were available for study, the underlying (pulmonary or non-pulmonary) primary disease cannot be definitively ascertained in the present case. No osseous changes were found on the ribs, but signs of osteoclastic resorption were observed on the dorsal surface of the sternal body, which might indicate a retrosternal or mediastinal location of the primary disease. Thus far, only a few archaeological case studies of secondary HOA reported signs of the presumed underlying primary disease, which was of a pulmonary nature in each of the individuals.

Scheuermann's disease in a juvenile male from the late Roman necropolis of Torrenueva (3rd-4th century CE, Granada, Spain)

This study details a severe case of Scheuermann's disease (SD) in a well-preserved skeleton of a juvenile male (designated TOR302), dated to 3rd-4th century CE, from the late Roman necropolis of Torrenueva (Granada, Spain). Individual TOR302 shows an evident kyphotic curve in the thoraco-lumbar spine, which is characterised by: (i) vertebral bodies of thoracic vertebra T2, thoracic segment T4-T9, and thoraco-lumbar segment T12-L2 wedged at >5°; (ii) slight anterior extensions of the epiphyseal ring; (iii) Schmorl's nodes on the superior and/or inferior plates; and (iv) a Cobb angle of 75°, derived from thoracic segments T4-T9. In addition, TOR302 shows other skeletal malformations as the secondary results of abnormal growth, due to altered biomechanical forces imposed by the spinal deformity, including: (i) lateral distortion of the spine that causes a slight secondary scoliotic curve; (ii) pelvic obliquity; and (iii) discrepancy in the length of the limbs. We argue that the secondary skeletal abnormalities allowed the individual to adapt to his spinal deformity meaning he was able to walk without the aid of a stick. Despite SD being a common modern clinical finding, few cases have been reported in ancient skeletal remains. This case therefore represents an important contribution to the palaeopathological literature.

Heads, Shoulders, Elbows, Knees, and Toes: Modular Gdf5 Enhancers Control Different Joints in the Vertebrate Skeleton

Synovial joints are crucial for support and locomotion in vertebrates, and are the frequent site of serious skeletal defects and degenerative diseases in humans. Growth and differentiation factor 5 (Gdf5) is one of the earliest markers of joint formation, is required for normal joint development in both mice and humans, and has been genetically linked to risk of common osteoarthritis in Eurasian populations. Here, we systematically survey the mouse Gdf5 gene for regulatory elements controlling expression in synovial joints. We identify separate regions of the locus that control expression in axial tissues, in proximal versus distal joints in the limbs, and in remarkably specific sub-sets of composite joints like the elbow. Predicted transcription factor binding sites within Gdf5 regulatory enhancers are required for expression in particular joints. The multiple enhancers that control Gdf5 expression in different joints are distributed over a hundred kilobases of DNA, including regions both upstream and downstream of Gdf5 coding exons. Functional rescue tests in mice confirm that the large flanking regions are required to restore normal joint formation and patterning. Orthologs of these enhancers are located throughout the large genomic region previously associated with common osteoarthritis risk in humans. The large array of modular enhancers for Gdf5 provide a new foundation for studying the spatial specificity of joint patterning in vertebrates, as well as new candidates for regulatory regions that may also influence osteoarthritis risk in human populations.

Joints, such as the hip and knee, are crucial for support and locomotion in animals, and are the frequent sites of serious human diseases such as arthritis. The Growth and differentiation factor 5 (Gdf5) gene is required for normal joint formation, and has been linked to risk of common arthritis in Eurasians. Here, we surveyed the mouse gene for the regulatory information that controls Gdf5's expression pattern in stripes at sites of joint formation. The gene does not have a single regulatory sequence that drives expression in all joints. Instead, Gdf5 has multiple different control sequences that show striking specificity for joints in the head, vertebral column, shoulder, elbow, wrist, hip, knee, and digits. Rescue experiments show that multiple control sequences are required to restore normal joint formation in Gdf5 mutants. The joint control sequences originally found in mice are also present in humans, where they are marked as active regions during fetal development and post-natal life, and map to a large region associated with arthritis risk in human populations. Regulatory variants in the human GDF5 control sequences can now be studied for their potential role in altering joint development or disease risk at particular locations in the skeleton.

Sex-related differences in the skeletal phenotype of aged vitamin D receptor global knockout mice

The role of the vitamin D receptor (VDR) in maintaining skeletal health appears to be complex and dependent on the physiological context. Global Vdr deletion in a mouse model (Vdr^-/-) results in hypocalcemia, secondary hyperparathyroidism and bone features typical of vitamin D-dependent rickets type II. When weanling Vdr^-/- mice are fed a diet containing high levels of calcium, phosphorus and lactose, termed the rescue diet, normalisation of serum calcium, phosphate and parathyroid hormone levels results in prevention of rickets at 10 weeks of age. However, 17 week old male Vdr^-/- mice, fed the rescue diet, have been reported as osteopenic due to a decrease in bone formation when compared to wild type mice. We now report confirmation of this finding with further data on the effect of the rescue diet on appendicular and axial skeletal structures in male and female Vdr^-/- mice at 26 weeks of age compared to Vdr^+/- controls. All Vdr^-/- mice were normocalcemic with no evidence of any mineralization defect. However, male Vdr^-/- mice exhibited significantly reduced mineral in femoral and vertebral bones when compared to control littermate Vdr^+/- mice, consistent with the previously reported data. In contrast, 26-week-old female Vdr^-/- mice demonstrated significantly increased femoral trabecular bone volume although there was decreased vertebral trabecular bone volume, similar to males, and femoral cortical bone volume was unchanged. Thus, the Vdr^-/- mouse model displays sex- and site-specific differences in skeletal structures with long-term feeding of a rescue diet. Although the global Vdr^-/- ablation does not permit the determination of skeletal mechanisms producing these differences, these data confirm skeletal changes even when fed the rescue diet.

Exome sequencing reveals two novel compound heterozygous XYLT1 mutations in a Polish patient with Desbuquois dysplasia type 2 and growth hormone deficiency

Desbuquois dysplasia type 2 (DBQD2) is a rare recessively inherited skeletal genetic disorder characterized by severe prenatal and postnatal growth retardation, generalized joint laxity with dislocation of large joints and facial dysmorphism. The condition was recently described to result from autosomal recessive mutations in XYLT1, encoding the enzyme xylosyltransferase-1. In this paper, we report on a Polish patient with DBQD2 who presented with severe short stature of prenatal onset, joint laxity, psychomotor retardation and multiple radiological abnormalities including short metacarpals, advanced bone age and exaggerated trochanters. Endocrinological examinations revealed that sleep-induced growth hormone (GH) release and GH peak in clonidine- and glucagon-induced provocative tests as well as insulin-like growth factor 1 (IGF-1) and IGF-binding protein-3 levels were all markedly decreased, confirming deficiency of GH secretion. Bone age, unlikely to GH deficiency, was significantly advanced. To establish the diagnosis at a molecular level, we performed whole-exome sequencing and bioinformatic analysis in the index patient, which revealed compound heterozygous XYLT1 mutations: c.595C>T(p.Gln199*) and c.1651C>T(p.Arg551Cys), both of which are novel. Sanger sequencing showed that the former mutation was inherited from the healthy mother, whereas the latter one most probably occurred de novo. Our study describes the first case of DBQD2 resulting from compound heterozygous XYLT1 mutation, expands the mutational spectrum of the disease and provides evidence that the severe growth retardation and microsomia observed in DBQD2 patients may result not only from the skeletal dysplasia itself but also from GH and IGF-1 deficiency.

Delayed developmental sequences in rodent diabetic embryopathy

Diabetes induced by alloxan at day 6 of gestation in Wistar rats produced decreased fetal growth, delayed skeletal ossification, decreased fetal kidney beta-glucuronidase, and an increased frequency of fetal birth defects which correlated with the degree of diabetic control. Offspring of severely diabetic mothers (mean blood glucose greater than 501 mg/dl) sacrificed at 20 days had a mean weight of 2.12 +/- 0.16 g, a mean of 1.8 +/- 0.46 caudal ossification centers, and a 28% incidence of birth defects as compared to 3.70 +/- 0.22 g, 5.9 +/- 0.42 caudal centers, and 1.1% defects for controls. Offspring of severely diabetic mothers sacrificed at 21 days had mean numbers of caudal and sternal ossification centers which did not significantly differ from controls, indicating that decreased ossification observed at 20 days of gestation is a delayed developmental sequence which is mostly corrected by 21 days. Offspring of moderately diabetic (mean blood glucose 300-500 mg/dl) and insulin-treated dams (mean blood glucose 152-168 mg/dl) had intermediate degrees of growth or ossification delay and birth defect frequency at both the 20- and 21-day sacrifices. Maternal diabetes also retards the developmental increase in fetal kidney beta-glucuronidase such than 20-day offspring of severely diabetic mothers had a mean specific activity of 1.1 nmol/min/mg compared to 3.0 nmol/min/mg for controls. The results support prior studies in rodents suggesting a progression of early growth delay, altered developmental sequences, and birth defects in diabetic pregnancy. This progression is suggested as a common teratogenic mechanism which has implications for evaluating analogous pregnancies in man.

Atlanto-occipital fusion and spondylolisthesis in an Anasazi skeleton from Bright Angel Ruin, Grand Canyon National Park, Arizona

The skeleton of a middle-aged female showing an unusual pattern of congenital, traumatic, and degenerative pathology was recovered from a small Kayenta Anasazi site located near the confluence of Bright Angel Creek with the Colorado River in the Inner Gorge of Grand Canyon. The atlas is fused with the base of the skull and C2 is fused with C3. The cervical region was subjected to hyperextension, perhaps through use of a tumpline, with resultant reduction of the neural canal to 8 mm, a condition that quite likely led to neurological problems. The skeleton also includes a depression fracture of the lateral condyle of the left tibia. Complete, bilateral spondylolysis of L5 led to an olisthesis of approximately 15 mm. The disc between L5 and S1 then ossified, most likely from staphylococcus bacteremia, making the olisthesis permanent and thereby creating a unique arachaeological specimen. Although spondylolysis is usually viewed as a stress fracture, the general pattern of pathology in this individual makes it necessary to consider an etiology of acute trauma.