Mesomelic dwarfism in pseudoachondroplasia

Pseudoachondroplasia (PSACH) is associated with mutations in the cartilage oligomeric matrix protein (COMP) gene and the clinical characteristics include short stature, deformities of the extremities involving the epiphyses and metaphyses, early onset arthritis, and ligament laxity. PSACH has been considered a rhizomelic form of dwarfism. So far no previous report has described mesomelic shortening of the limbs in PSACH. We reviewed nine patients with a diagnosis of PSACH based on clinical and radiographic examination and mutation analysis of the COMP gene. The mean height in the adults was 116 cm. All patients showed mesomelic dwarfism. The average ratios of radial length to humeral length and tibial length to femoral length were 0.62 and 0.63, respectively. The tibia and the radius showed more severe bony deformity than the femur and humerus. The degree of short stature was related to the site of the mutation in the COMP gene, but there was no correlation between bony deformity and height or gene mutation.     

An effective case of growth hormone treatment on cartilage-hair hypoplasia

Cartilage-hair hypoplasia (CHH) is an autosomal recessive metaphyseal chondrodysplasia characterized by severe short-limb short stature and hypoplastic hair. The responsible gene for CHH has been identified to be ribonuclease of mitochondrial RNA-processing (RMRP) gene. We examined RMRP genes of a 3-year-old Japanese CHH boy and his family and revealed a novel mutation: 20 bp duplication (TACTCTGTGAAGCTGAGGAC), in promoter region of maternal allele, at nucleotide -3 and a reported 218A>G point mutation in transcribed region of paternal allele. No treatment for CHH has been established so far. Growth hormone (GH) action has its effect on linear growth and on bone remodeling and homeostasis. Recently, GH has been used to improve severe short stature caused by not only GH deficiency (GHD) but also some skeletal dysplasias including achondroplasia. To improve severe short stature, we treated the patient with 0.175 mg kg-1 week-1 of GH for 7 years. His height was improved from -4.2 SD to -3.0 SD by 1 year of GH treatment. Following treatment had given positive effects continuously on his height to -2.6 SD by 3.1 years GH medication. Then, when he was 6 years old, surgical lengthening was performed and his height reached to -2.0 SD. After the surgery, we continued GH treatment. Additional GH treatment of 3.6 more years had kept his height to -2.0 SD. However, when he was 8 years old, because there was an interruption of GH treatment, the velocity of his height was obviously decreased comparing before and during the interruption, which was calculated 3.4 and 2.2 cm/year, respectively, and the SD score was decreased to -2.1 SD. This result of total 7 years of GH treatment suggested that GH treatment significantly improved his disturbed bone growth and had also positive efficacy to keep growth rate. This result implies the connection between GH signal and RMRP gene. Additionally, GH may be considered to be an efficient treatment for CHH.     

Metatropic Dysplasia of Nonlethal Variant in a Chinese Child – A Case Report

Metatropic dysplasia (MD), is a rare skeletal dysplasia occurring predominantly in infants characterized by a distinctive long torso and short limbs; it is as a result of mutations in the TRPV4 gene. However, a clear distinction between various forms of skeletal dysplasias caused by the transient receptor potential vanilloid 4 (TRPV4) gene is difficult but could be achieved by a combination of gene sequencing, medical and radiological criteria. We hereby report a case of a 14‐month old girl who presented with an abnormal stature. The diagnosis of nonlethal MD was confirmed by X‐ray with dumbbell‐shaped long bones, platyspondyly, and delayed carpal ossification, as well as broadened pelvis with marginally widened ilia, epiphyseal plates, and slightly flattened acetabula. Furthermore, gene sequencing confirmed gene mutation on exon 15 of the TRPV4 gene with a heterozygous missense mutation (c.2396C > T), but no mutation was present in her parents. Our findings recorded metatropic dysplasia with the c.2396C > T mutation in the TRPV4 gene in China. This mutation caused changes in amino acid of TRPV4, which can induce growth retardation in children.     

Limb lengthening in achondroplasia

Background:Stature lengthening in skeletal dysplasia is a contentious issue. Specific guidelines regarding the age and sequence of surgery, methods and extent of lengthening at each stage are not uniform around the world. Despite the need for multiple surgeries, with their attendant complications, parents demanding stature lengthening are not rare, due to the social bias and psychological effects experienced by these patients. This study describes the outcome and complications of extensive stature lengthening performed at our center.Results:Nine patients aged five to 25 years (mean age 10.2 years) underwent limb lengthening procedures for 18 tibiae, 10 femora and 8 humeri. Four patients underwent bilateral lengthening of all three segments. The mean length gain for the tibia, femur and humerus was 15.4 cm (100.7%), 9.9 cm (52.8%) and 9.6 cm (77.9%), respectively. Healing index was 25.7, 25.6 and 20.6 days/cm, respectively, for the tibia, femur and humerus. An average of 33.3% height gain was attained. Lengthening of both tibia and femur added to projected height achieved as the 3^rd percentile of standard height in three out of four patients. In all, 33 complications were encountered (0.9 complications per segment). Healing index was not affected by age or bone segment.Conclusion:Extensive limb lengthening (more than 50% over initial length) carries significant risk and should be undertaken only after due consideration.     

Growth hormone deficiency following radiation therapy of primary brain tumors in children

The medical records of 123 patients treated for brain tumors at Children's Hospital and Medical Center, Seattle, Washington, between 1985 and 1987 were reviewed. The endocrinological complications of radiation therapy and the effectiveness of growth hormone (GH) replacement therapy were assessed. These were the first 2 years after synthetic GH became available. The disease pathology was confirmed at craniotomy or biopsy in 108 patients. Ninety-five children completed radiation therapy and 65 of these were alive at the time of review; these 65 children represent the study population. The most common tumor types were medulloblastoma, craniopharyngioma, and ependymoma. Endocrine evaluation was initiated with changes in the patients' growth velocity. Patient workup included skeletal x-ray films for determination of bone and analysis of thyroxin, thyroid-stimulating hormone, and somatomedin-C levels. Following 1-dopa and clonidine stimulation, provocative studies of GH levels were performed. Growth hormone failure and short stature were observed in 26 children, most commonly in the 2nd year after tumor treatment. Eight patients with GH failure were also hypothyroid. Hormone replacement therapy was initiated with recombinant GH, 0.05 mg/kg/day, and all children so treated showed an increase in height, with eight patients experiencing catch-up growth. There were no complications of therapy or tumor recurrence. Studies of baseline bone age and somatomedin-C levels on completion of radiation therapy are recommended. Comprehensive endocrine studies should follow changes in the patients' growth velocity. With early GH replacement, catch-up growth is possible and normal adult heights may be achieved.     

A common FGFR3 mutation functions as a diagnostic marker for achondroplasia-group disorders in the Japanese population

Recent DNA studies performed by several groups have detected mutations of the gene encoding fibroblast growth factor receptor 3 (FGFR3) in patients with achondroplasia-group disorders, including achondroplasia (ACH), hypochondroplasia (HCH), and thanatophoric dysplasia (TD). For this study, we analyzed theFGFR3 gene in 31 Japanese patients with typical ACH, four with HCH, three with a condition intermediate between ACH and HCH (ACH/HCH-intermediate), and one with TD. Of the 31 typical ACH patients, 29 showed a G1138 to A transition and the other two a G1138 to C transversion, both resulting in a common Gly380Arg substitution in the transmembrane domain of FGFR3. The one TD and the four HCH patients did not display any mutations in the transmembrane domain of FGFR3. Of the three ACH/HCH-intermediate cases, one patient showed the Gly380Arg substitution and one did not, and further analysis of the second patient revealed the presence of Asn540Lys substitution. The first patient was, therefore, genotypically diagnosed as ACH and the second as HCH. Peripheral blood leukocyte DNA analysis in the remaining ACH/HCH-intermediate patient indicated an unequal ratio of mutant to normal PCR products, possibly representing a somatic mosaic for the Gly380Arg mutation. Analysis of the common FGFR3 mutation thus appears to help in the molecular diagnosis of patients with achondroplasia-group disorders.     

Total Hip Arthroplasty Reduces Pain and Improves Function in Patients With Spondyloepiphyseal Dysplasia: A Long-Term Outcome Study of 50 Cases

Background

Spondyloepiphyseal dysplasia (SED) is rare genetic condition which leads to skeletal and joint deformities that can predispose patients to degenerative joint disease. There are limited reports on the results of total hip arthroplasty (THA) in this patient population. The purpose of this study is to review clinical and radiographic outcomes of THA performed in patients with SED at one institution.

Pseudoachondroplasia: A rare cause of rhizomelic dwarfism

Pseudoachondroplasia is a rare rhizomelic short-limbed skeletal dysplasia. Its inheritance is varied; autosomal dominant pattern and germline or somatic mutations can occur. Children at 2–3 years of age present with short height, gait disturbances, or limb deformities. Characteristic skeletal changes include shortening of long bones, predominantly of femur and humerus with irregular, flared metaphysis and fragmented epiphysis. Platyspondyly is also present, but the interpedicular distance is normal. The diagnosis is essentially based on imaging, and thus, it is important to be aware of the radiological features. Here, we report a case of two brothers where the elder sibling had classical radiological features of pseudoachondroplasia, whereas the younger one had early changes of this disorder.     

Bone structure in two adult subjects with impaired minor spliceosome function resulting from RNU4ATAC mutations causing microcephalic osteodysplastic primordial dwarfism type 1 (MOPD1)

Microcephalic osteodysplastic primordial dwarfism type 1 (MOPD1), or Taybi-Linder syndrome is characterized by distinctive skeletal dysplasia, severe intrauterine and postnatal growth retardation, microcephaly, dysmorphic features, and neurological malformations. It is an autosomal recessive disorder caused by homozygous or compound heterozygous mutations in the RNU4ATAC gene resulting in impaired function of the minor spliceosome. Here, we present the first report on bone morphology, bone density and bone microstructure in two adult MOPD1 patients and applied radiographs, dual energy X-ray absorptiometry, high-resolution peripheral quantitative computed tomography and biochemical evaluation.The MOPD1 patients presented with short stature, low BMI but normal macroscopic bone configuration. Bone mineral density was low. Compared to Danish reference data, total bone area, cortical bone area, cortical thickness, total bone density, cortical bone density, trabecular bone density and trabecular bone volume per tissue volume (BV/TV) were all low. These findings may correlate to the short stature and low body weight of the MOPD1 patients. Our findings suggest that minor spliceosome malfunction may be associated with altered bone modelling.     

Bone robusticity in two distinct skeletal dysplasias diverges from established patterns

Achondroplasia (ACH) is a heritable disorder of endochondral bone formation characterized by disproportionate short stature. Osteogenesis imperfecta (OI) is a heritable bone and connective tissue disorder characterized by bone fragility. To investigate bone morphology of these groups, we retrospectively reviewed 169 de‐identified bone age films from 20 individuals with ACH, 39 individuals with OI and 37 age‐ and sex‐matched controls (matched to historical measurements from the Bolton–Brush Collection). We calculated robustness (Tt.Ar/Le) and relative cortical area (Ct.Ar/Tt.Ar) from measurements of the second metacarpal, which reflect overall bone health. Relative cortical area (RCA) is a significant predictor of fracture risk and correlates with robustness at other sites. Individuals with OI had RCH values above and robustness values below that of the control population. Bisphosphonate treatment did not significantly impact either robustness or RCA. In contrast to that reported in the unaffected population, there was no sexual dimorphism found in OI robustness or relative cortical area. We suggest that the underlying collagen abnormalities in OI override sex‐specific effects. Individuals with ACH had robustness values above and RCA values below that of the control population. Sexual dimorphism was found in ACH robustness and RCH values. Clinical significance: Identifies morphologic trends in two distinct skeletal dysplasia populations (OI and ACH) to better understand development of bone robusticity and slenderness in humans. Understanding these patterns of bone morphology is important to predict how individuals will respond to treatment and to increase treatment effect. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2392–2396, 2017.

     

Hadju-Cheney syndrome: response to therapy with bisphosphonates in two patients.

Hadju-Cheney syndrome is characterized by short stature, distinctive facies, and a slowly progressive skeletal dysplasia including acro-osteolysis. Autosomal dominant inheritance is typical, but the genetic defect and molecular pathogenesis of the syndrome are unknown. Osteoporosis with atraumatic fracture is a frequent finding, and previous studies have documented biochemical and morphometric evidence of high bone turnover. Here, we report the clinical details and response to therapy with bisphosphonates in two patients (mother and son) with Hadju-Cheney syndrome and postulate that osteoclast-mediated bone resorption is important in the generalized osteoporosis commonly associated with this condition.     

Tricho-rhino-phalangeal syndrome in a 13-year-old girl with chronic renal failure and severe growth retardation

Introduction: The tricho-rhino-phalangeal syndrome type III (TRPS III) is a rare autosomal dominantly inherited condition. The main clinical features are sparse and slow-growing hair and nails, a pear-shaped nose with a bulbous tip, elongated and flat philtrum, thin upper lip, cone-shaped epiphyses of the phalanges, and short stature. All patients have a point mutation in the TRPS1 gene. Case report: In this paper, we present a 13-year-old female with the typical clinical features of TRPS III, extreme growth retardation, severe deformities of both proximal radii resulting in limited extension of the elbows, and chronic renal failure (CRF) in addition. Molecular diagnostics revealed a missense mutation in exon 6 of TRPS1 that she inherited from her father who is also affected with TRPS III, but does not have CRF. In the index patient, the CRF was found to be due to bilateral renal hypodysplasia (RHD). Conclusion: Beside the renal dysplasia, the girl had severe deformities of the proximal radii – findings which have not been reported so far in TRPS III.     

Cervical kyphosis in diastrophic dysplasia.

STUDY DESIGN: An evaluation of cervical kyphosis in diastrophic dysplasia from newborn to adult life. OBJECTIVES: To discover the prevalence and natural history of cervical kyphosis in diastrophic dysplasia. SUMMARY OF BACKGROUND DATA: Typical findings in this rare skeletal dysplasia are sport-limbed short stature, multiple joint contractures, early degeneration of joints, and spinal deformities such as cervical kyphosis, scoliosis, and exaggerated lumbar lordosis. In diastrophic dysplasia, spontaneous resolution of cervical kyphosis has been reported, but so have severe forms causing medullar compression leading to quadriplegia and death. The prevalence and clinical outcome of the kyphosis are not known. METHODS: The radiographic natural history of the cervical spine was studied in 120 patients. They varied in age from newborns to 63-year-olds. The average follow-up time in 26 living patients with cervical kyphosis was 10.0 years. RESULTS: Midcervical kyphosis was noted in 29 patients (24%) in their first radiograph. In 25 patients, the first radiographs were taken before the age of 18 months, and 24 of these patients (96%) had cervical kyphosis. The most severe case was that of a 32-year-old patient with a 165 degrees kyphosis. In the 24 patients, the kyphosis resolved spontaneously at an average age of 7.1 years. Three patients with a severe kyphosis died; one patient is alive. One patient, a 4-year-old child has mild resolving deformity. CONCLUSIONS: Cervical kyphosis in diastrophic dysplasia usually is shown at the time of birth. It resolves spontaneously during growth and seldom needs treatment. Careful follow-up study and treatment, if necessary, are important tools for avoiding the neurologic problems and fatal outcome.     

Distraction osteogenesis of the lower extremity in patients with achondroplasia/hypochondroplasia treated with transplantation of culture-expanded bone marrow cells and platelet-rich plasma

BACKGROUND: Longer treatment period in distraction osteogenesis (DO) of the lower extremity leads to more frequent complications. We have developed a new technique of transplantation of culture-expanded bone marrow cells (BMCs) and platelet-rich plasma (PRP) during DO to accelerate new bone formation. To assess the efficacy of this cell therapy, retrospective comparative study was conducted between the bones treated with BMC and PRP and the bones treated without BMC and PRP during DO in patients with achondroplasia (ACH) and hypochondroplasia (HCH). METHODS: Fifty-six bones in 20 patients (ACH, 16; HCH, 4) that were lengthened in our hospital were divided into 2 groups. Twenty-four bones (femora, 12; tibiae, 12) in 11 patients (boys, 7; girls, 4) were treated with BMC and PRP transplantation (BMC-PRP group), whereas 32 bones (femora, 14; tibiae, 18) in 9 patients (boys, 3; girls, 6) did not undergo additional cell therapy (control group). The parameters, including the age at operation, the increase in length, and the healing index, were compared between the 2 groups. The clinical outcome was also compared between the femoral and tibial lengthenings. RESULTS: Bone marrow cells (average number, +/- SD, 3.2 +/- 1.37 x 10 cells) and PRP (average platelet concentration +/- SD, 2.36 +/- 0.57 x 10 cells/muL) were transplanted. Although there were no significant differences in the age at operation and the length gained between the 2 groups, the average healing index of the BMC-PRP group (27.1 +/- 6.89 d/cm) was significantly lower than that of the control group (36.2 +/- 10.4 d/cm) (P = 0.0005). The femoral lengthening showed significantly faster healing than did the tibial lengthening in the BMC-PRP group (P = 0.0092). CONCLUSIONS: Transplantation of BMC and PRP shortened the treatment period by accelerating new bone regeneration during DO of the lower extremity in patients with ACH and HCH, especially in the femoral lengthening.     

病灶清除、植骨联合内固定治疗下肢长管状骨纤维结构不良的疗效和并发症观察

背景：骨纤维结构不良临床上可表现为单发或多发的骨骼畸形、疼痛和病理性骨折。目前该病的治疗方法以手术清除病灶、植骨内固定为主。目的：探讨病灶清除、植骨联合髓外固定治疗下肢长管状骨纤维结构不良的疗效和可行性。方法方法：选取2010年2月至2012年11月我院收治的15例骨纤维结构不良患者的病例资料进行回顾性分析,男8例,女7例;年龄26-48岁,平均（32.1±1.2）岁;股骨9例,胫骨6例。均采用病灶清除,取髂骨植骨,动力髋螺钉或锁定接骨板固定。围手术期予抗炎、补液对症处理,术后石膏固定,指导患者功能锻炼。髋关节功能按Harris评分系统评定。膝关节功能按Merchan评分系统评定。术后定期摄X线片,观察肿瘤复发情况,植骨融合情况和不良反应发生情况。结果：所有伤口均甲级愈合,按期拆线。所有患者均完成18个月随访,无1例复发,植骨均融合,术后部分负重下地时间（4.3±0.6）个月,X线片未见骨溶解,术后（4.0±0.8）个月可见新生骨长入,2例患者残留手术区疼痛,对症治疗后缓解。术后髋关节功能Harris评分为97.2分,膝关节功能Merchan评分为95.8分,均较术前显著提高（P〈0.05）。结论：病灶清除、植骨联合髓外固定在下肢长管状骨纤维结构不良患者中固定可靠,预后佳,是一种可行的治疗方法。     

Preoperative halo-gravity traction with and without thoracoscopic anterior release for skeletal dysplasia patients with severe kyphoscoliosis

Purpose

Recent work has shown the safety and efficacy of halo-gravity traction as an operative adjunct. However, there are no reports specifically looking at halo-gravity traction in patients with skeletal dysplasia. Our purpose was to assess the safety and efficacy of traction in children with skeletal dysplasia who present with severe kyphoscoliosis.

Methods

We retrospectively reviewed eight consecutive children with skeletal dysplasia who were treated with halo-gravity traction preoperatively. Six of the patients had a thoracoscopic anterior release prior to the halo-gravity traction. All patients were ambulatory and presented with severe, rigid kyphoscoliosis.

Results

The mean duration of traction was 32 days. There were no neurologic complications with traction or after posterior spinal instrumentation. The majority of kyphoscoliosis correction was with the halo-gravity traction alone: major curve (MC) Cobb angle improved 41 %; C7–center sacral vertical line, 75 %; C7–MC apex, 21 %; and T2–T12 kyphosis, 35 %. Trunk height increased 37 % and thoracic height 44 %. An additional amount of correction was obtained with posterior spinal instrumentation (±fusion), decreasing MC Cobb angle an additional 23 %; C7–apex, 16 %; and T2–T12 kyphosis, 10 %. There was no additional correction of thoracic height. Two years after posterior spinal instrumentation (±fusion), a mild-to-moderate amount of correction was lost: MC Cobb angle decreased 23 %; compensatory Cobb angle, 28 %; C7–CSVL, 24 %; C7–S1, 22 %; regional kyphosis, 31 %; thoracic kyphosis, 29 %; and trunk height, 27 %.

Conclusions

Among children with skeletal dysplasia and severe kyphosis, halo-gravity traction is well tolerated and safe. Most of the corrections in radiographic parameters were achieved with traction alone. Traction improves coronal balance, apical translation, thoracic height, and kyphosis. In this specific population, the potential for neurologic injury during corrective surgery is high. However, preoperative halo-gravity traction provides slow, progressive correction in a safe manner and avoided neurologic injury in these patients. This study did not compare patients without halo-gravity traction to patients with halo-gravity traction, therefore it cannot be concluded that going straight to instrumentation without traction will give a poorer radiographic result.

Level of evidence

IV.

     

Upper cervical spine instability in pseudoachondroplasia

BACKGROUND: Pseudoachondroplasia (PSACH) is a rare autosomal dominant skeletal dysplasia associated with os odontoideum and atlantoaxial instability. This study aims to define the characteristics of upper cervical spine instability in patients with PSACH and analyze the relation between the incidence of upper cervical instability and os odontoideum. METHODS: Fifteen patients (10 women and 5 men) with PSACH of Korean ethnicity with mean age of 23.7 years (range, 3-44 years) at presentation to our hospital with varied complaints, including short stature, limb deformity, neck pain, and neurological symptoms, were evaluated clinicoradiologically for upper cervical spine instability. The patients were separated into group 1 (n = 9) with os odontoideum and group 2 (n = 6) without os odontoideum. Comparisons were made using parameters such as instability index, rotational instability, atlantodens interval and space available for cord, and analysis done to correlate cervical instability with age and Japanese Orthopedic Association (JOA) score. RESULTS: Significant differences were found statistically when the 2 groups were compared on the basis of the space available for the cord (SAC), JOA scoring, and rotational instability. Linear relationship was found between instability and age and JOA score. Incidence of os odontoideum was 60% in our study group. CONCLUSIONS: Os odontoideum led to an increase in the incidence of upper cervical spine instability. Instability increased with the age. The presence of os odontoideum and atlantoaxial instability did not warrant for surgery because no signs of cervical myelopathy developed or progressed in our patients during the follow-up period, but these patients should undergo regular clinical and radiological evaluation. LEVEL OF EVIDENCE: Level IV prognostic study.     

Vertebral morphology in aromatase inhibitor–treated males with idiopathic short stature or constitutional delay of puberty

Aromatase inhibitors (AIs), blockers of estrogen biosynthesis, delay bone maturation and therefore are used increasingly to promote growth in children and adolescents with growth disorders. The effects of treatment on skeletal health are largely unknown. Since estrogen deficiency is associated with various detrimental skeletal effects, we evaluated in this cross‐sectional posttreatment study vertebral body morphology, dimensions and endplates, and intervertebral disks by the use of magnetic resonance imaging (MRI) in two cohorts of males previously treated with the AI letrozole or placebo. Males with idiopathic short stature received treatment with letrozole or placebo for 2 years during prepuberty or early puberty; males with constitutional delay of puberty received letrozole or placebo in combination with low‐dose testosterone for 1 year during early or midpuberty. In males with idiopathic short stature, mild vertebral body deformities were found in 5 of 11 (45%) letrozole‐treated subjects, whereas in the placebo group no deformities were detected (p = .01). In the cohort of males with constitutional delay of puberty, a high prevalence of endplate and intervertebral disk abnormalities was observed in both the letrozole‐ and the placebo‐treated groups. We conclude that AI therapy during prepuberty or early puberty may predispose to vertebral deformities, which probably reflect impaired vertebral body growth rather than impaired bone quality and compression fractures. If AIs are used in growth indications, follow‐up of vertebral morphology is indicated. © 2010 American Society for Bone and Mineral Research     

Spondyloepiphyseal dysplasia in three generations

Spondyloepiphyseal dysplasia is a heterogeneous group of disorders characterized by growth abnormalities in the epiphyses and spine. The purpose of this study is to present a rare case of three patients with a congenital type of spondyloepiphyseal dysplasia, all members of a single family spanning three generations. Interestingly, each one presented with variable radiographic severity and clinical picture. Spondyloepiphyseal dysplasia is a disorder that should always be taken into consideration during investigations of short stature. The relevant literature is presented and discussed.