Advances in understanding etiology of achondroplasia and review of management

Mutational analysis of consanguineous families and their targeted therapy against dwarfism

Dwarfism is a medical term used to describe individuals with a height-vertex measurement that falls below two standard deviations (-2SD) or the third percentile for their gender and age. Normal development of growth is a complicated dynamic procedure that depends upon the coordination of different aspects involving diet, genetics, and biological aspects like hormones in equilibrium. Any severe or acute pathologic procedure may disturb the individual's normal rate of growth. In this research, we examined four (A-D) Pakistani consanguineous families that exhibited syndromic dwarfism, which was inherited in an autosomal recessive pattern. The genomic DNA of each family member was extracted by using phenol-chloroform and Kit methods. Whole Exome Sequencing (WES) of affected family members (IV-11, III-5, IV-4 and III-13) from each group was performed at the Department of Medical Genetics, University of Antwerp, Belgium. After filtering the exome data, the mutations in PPM1F, FGFR3, ERCC2, and PCNT genes were determined by Sanger sequencing of each gene by using specific primers. Afterward, FGFR3 was found to be a suitable drug target among all the mutations to treat achondroplasia also known as disproportionate dwarfism. BioSolveIT softwares were used to discover the lead active inhibitory molecule against FGFR3. This research will not only provide short knowledge to the concerned pediatricians, researchers, and family physicians for the preliminary assessment and management of the disorder but also provide a lead inhibitor for the treatment of disproportionate dwarfism.Communicated by Ramaswamy H. Sarma.

Real-world evidence in achondroplasia: considerations for a standardized data set

BACKGROUND

Collection of real-world evidence (RWE) is important in achondroplasia. Development of a prospective, shared, international resource that follows the principles of findability, accessibility, interoperability, and reuse of digital assets, and that captures long-term, high-quality data, would improve understanding of the natural history of achondroplasia, quality of life, and related outcomes.

METHODS

The Europe, Middle East, and Africa (EMEA) Achondroplasia Steering Committee comprises a multidisciplinary team of 17 clinical experts and 3 advocacy organization representatives. The committee undertook an exercise to identify essential data elements for a standardized prospective registry to study the natural history of achondroplasia and related outcomes.

RESULTS

A range of RWE on achondroplasia is being collected at EMEA centres. Whereas commonalities exist, the data elements, methods used to collect and store them, and frequency of collection vary. The topics considered most important for collection were auxological measures, sleep studies, quality of life, and neurological manifestations. Data considered essential for a prospective registry were grouped into six categories: demographics; diagnosis and patient measurements; medical issues; investigations and surgical events; medications; and outcomes possibly associated with achondroplasia treatments.

CONCLUSIONS

Long-term, high-quality data are needed for this rare, multifaceted condition. Establishing registries that collect predefined data elements across age spans will provide contemporaneous prospective and longitudinal information and will be useful to improve clinical decision-making and management. It should be feasible to collect a minimum dataset with the flexibility to include country-specific criteria and pool data across countries to examine clinical outcomes associated with achondroplasia and different therapeutic approaches.

Preterm birth risk in women with skeletal dysplasias and short stature

PURPOSE

The primary objective was to estimate the risk of preterm delivery in a population of women with a skeletal dysplasia and short stature. The secondary outcome was to identify factors that increase the risk of preterm delivery.

METHODS

A cross sectional survey was performed asking detailed pregnancy and reproductive health questions, aimed at a convenience sample of women who were little people, administered through Little People of America, Little People UK, Little People Canada, and the World Dwarf Games. Comparisons were made on gestational age at delivery between pregnancies with and without the outcomes.

RESULTS

The survey had a response rate of 74% (117/158). There was a total of 55 eligible subjects who had 72 live births. Delivery prior to 37 weeks occurred in 19/72 live births, which equates to a preterm birth rate of 26.4%. Besides short stature, no single factor was identified that could solely explain the elevated preterm birth risk in the study population.

CONCLUSION

The risk of preterm delivery in women with skeletal dysplasias and short stature is elevated compared to the general population. This information will assist healthcare providers in pregnancy management and counseling.

Sagittal alignment at 3 years old determines future thoracolumbar kyphosis in achondroplasia: A prospective study with minimum 5-year follow-up from infancy

Background

Little is known about the progression of Thoracolumbar kyphosis (TLK) in achondroplasia. The aim of the study was to evaluate natural progression of TLK and establish risk factors for progression.

Methods

We reviewed 21 patients (11 males, 10 females) diagnosed clinically and radiographically with achondroplasia as infants and followed for a minimum of 5 years from infancy, and analyzed to compare differences between data at 0, 1, 3, 5, 7-10, and 11-18 years old. Subjects (n=21) were divided into two groups with and without TLK >20° at the thoracolumbar junction on lateral standing radiographs at age 3.

Results

TLK >20° occurs in 76.2% of infants in the first 7 months of life. Sagittal parameters at 0, 1, 3, 5, 7-10, and 11-18 years old differed significantly for cervical lordosis (CL), thoracic kyphosis (TK), TLK, lumbar lordosis (LL), pelvic tilt (PT), and sacral slope (SS). TK, LL, and SS increased significantly with increasing age, whereas CL, TLK, and PT were significantly lower in older age groups (P < 0.05). In 6 of 7 patients with TLK >20° at age 3, TLK had progressed or was still >20° at age 5. The prevalence of TLK >20° at age 3 was 33.3% (7/21). There was a significant difference in age at independent walking among subjects with and without TLK at age 3 (31.4±17.1 vs. 16.1±3.4 months, P < 0.01). Radiologic parameters associated with TLK showed significant differences between subjects with and without TLK at age 3, including TLK, TK, TLK, LL, and SVA at age 5; and TLK at ages 7-10 and 11-18.

Conclusions

These results suggest that sagittal alignment at 3 years old determines future TLK in achondroplasia. Progression of deformity and neurological impairments require consideration in treatment planning.

Quality of life in adults with achondroplasia in the United States

Studies examining quality of life (QoL) in adults with achondroplasia are limited. We report on QoL and psychiatric illness diagnoses in a modern cohort of adults with achondroplasia. SF-36 Health Survey scores from adults with achondroplasia were compared to general population scores. Demographics, physical measurements, and psychiatric illness diagnoses were recorded from medical records. The achondroplasia population had lower scores than the general population in all categories. Most people with achondroplasia (56%) had a diagnosed psychiatric illness. Those with a diagnosed psychiatric illness had lower scores in physical functioning, role limitations due to physical and emotional health, and mental health. Pain, energy/fatigue, and general health scale scores were roughly equivalent (<2 points difference). Social functioning was >15 points higher in individuals with psychiatric illness diagnoses. Adults with achondroplasia report significantly lower physical and mental well-being and had nearly 3× the rate of psychiatric illness diagnosis than the general population, highlighting the importance of total care for this population. Healthcare providers must understand the physical and mental comorbidities of achondroplasia, beyond short stature and orthopedic issues, so they can proactively improve QoL across the lifespan for patients and families.

Health assessment of patients with achondroplasia, pseudoachondroplasia, and rickets based on 3D non-linear diagnostics

The goal of this study was to analyze diminishment of the functional status of the skeleton, parts of organs, regions of the brain, connective tissues, and chondrocytes in patients with achondroplasia (ACH), pseudoachondroplasia (PSACH), and rickets. Three-dimensional non-linear scanning (3D-NLS) was used to analyze the functional status of patients with genetic bone disorders, including 7 patients with ACH, 3 patients with PSACH, and 3 patients with rickets. Results indicated that the percentage of patients with long bones in the decompensatory phase did not differ depending on whether they had ACH, PSACH, or rickets. Joints in the decompensatory phase did not differ in patients with ACH except for the right hip (16.67%). Various joints were in the decompensatory phase (16.7-33.3%) in patients with rickets. The thoracic vertebrae, lumbar vertebrae, and liver were in the decompensatory phase in all 3 groups of patients. Connective tissues were in the decompensatory phase in 33.33% of patients with ACH. None of the patients with PSACH had chondrocytes in the decompensatory phase but 66.67% of patients with ACH or rickets did. Regions of the brain in the decompensatory phase were most prevalent in patients with rickets or ACH but not in patients with PSACH. In conclusion, diagnosis based on 3D-NLS was able to identify the functional status of genetic bone disorders. Some areas of decompensation were common to the 3 diseases studied but other areas were specific to a given disease.

Current knowledge of medical complications in adults with achondroplasia: A scoping review

This article provides an overview of the current knowledge on medical complications, health characteristics, and psychosocial issues in adults with achondroplasia. We have used a scoping review methodology particularly recommended for mapping and summarizing existing research evidence, and to identify knowledge gaps. The review process was conducted in accordance with the PRISMA‐ScR guidelines (Preferred Reporting Items for Systematic reviews and Meta‐Analyses Extension for Scoping Reviews). The selection of studies was based on criteria predefined in a review protocol. Twenty‐nine publications were included; 2 reviews, and 27 primary studies. Key information such as reference details, study characteristics, topics of interest, main findings and the study author's conclusion are presented in text and tables. Over the past decades, there has only been a slight increase in publications on adults with achondroplasia. The reported morbidity rates and prevalence of medical complications are often based on a few studies where the methodology and representativeness can be questioned. Studies on sleep‐related disorders and pregnancy‐related complications were lacking. Multicenter natural history studies have recently been initiated. Future studies should report in accordance to methodological reference standards, to strengthen the reliability and generalizability of the findings, and to increase the relevance for implementing in clinical practice.

Sustained hip flexion contracture after femoral lengthening in patients with achondroplasia

Background

Hip flexion contracture often occurs after femoral lengthening in patients with achondroplasia, but few studies have investigated its development in these patients. The purpose of this study was to analyze sustained hip flexion contracture in achondroplasia patients who underwent femoral lengthening and to identify contributing factors.

Methods

This study included 34 patients with achondroplasia who underwent femoral lengthening (mean age at operation, 11.1 years). Sustained hip flexion was defined as flexion contracture lasting > 6 months postoperatively despite physiotherapy. Demographic data, spinopelvic parameters (pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, and sagittal vertical axis), and quantitative assessments of femoral lengthening were investigated. The associations among these factors and the development of sustained hip flexion contracture were assessed.

Results

Sustained hip flexion contracture developed in 13 (38%) of 34 achondroplasia patients after femoral lengthening. Eight (62%) of these 13 patients concomitantly exhibited limitation of knee flexion. Excessive femoral lengthening (odds ratio [OR], 1.450; 95% confidence interval [CI], 1.064 to 1.975; p = 0.019) and forward sagittal vertical axis tilt (OR, 1.062; 95% CI, 1.001 to 1.127; p = 0.047) contributed to sustained hip flexion contracture.

Conclusions

Sustained hip flexion contracture frequently occurs after femoral lengthening in achondroplasia patients. Both excessive femoral lengthening and preoperative forward SVA tilt may contribute to the development of sustained hip flexion contracture in these patients.

Achondroplasia: Etiology, Clinical Presentation, and Management

By using a literature review, this article examines the implications of achondroplasia. The following areas are discussed: the clinical definition of the disease; the incidence, etiology, and pathogenesis; phenotypical characteristics and natural history of the disease; and management, recurrence risk, and genetic counseling. Lastly, implications for nursing in relation to achondroplasia are discussed.

Identification and in silico characterization of p.G380R substitution in FGFR3, associated with achondroplasia in a non-consanguineous Pakistani family

Background

The dimerization efficiency of FGFR3 transmembrane domain plays a critical role in the formation of a normal skeleton through the negative regulation of bone development. Recently, gain-of-function mutations in the transmembrane domain of FGFR3 has been described associated with an aberrant negative regulation, leading to the development of achondroplasia-group disorders, including achondroplasia (ACH), hypochondroplasia (HCH) and thanatophoric dysplasia (TD). Here, we describe a non-consanguineous Pakistani family with achondroplasia to explain hereditary basis of the disease.

Methods

PCR-based linkage analysis using microsatellite markers was employed to localize the disease gene. Gene specific intronic primers were used to amplify the genomic DNA from all affected as well as phenotypically healthy individuals. Amplified PCR products were then subjected to Sanger sequencing and RFLP analysis to identify a potentially pathogenic mutation. The impact of identified mutation on FGFR3 protein’s structure and stability was highlighted through different bioinformatics tools.

Results

Genetic screening of the family revealed a previously reported heterozygous c.1138 G > A (p.G380R) mutation in the coding exon 8 of FGFR3 gene. Identified genetic variation was confirmed in all affected individuals while healthy individuals and controls were found genotypically normal. The results were further validated by RFLP analysis as c.1138 G > A substitution generates a unique recognition site for SfcI endonuclease. Following SfcI digestion, the electrophoretic pattern of three bands/DNA fragments for each patient is indicative of heterozygous status of the disease allele. In silico studies of the mutant FGFR3 protein predicted to adversely affect the stability of FGFR3 protein.

Conclusions

Mutation in the transmembrane domain may adversely affect the dimerization efficiency and overall stability of the FGFR3, leading to a constitutively active protein. As a result, an uncontrolled intracellular signaling or negative bone growth regulation leads to achondroplasia. Our findings support the fact that p.G380R is a common mutation among diverse population of the world and like other countries, can be used as a molecular diagnosis marker for achondroplasia in Pakistan.

Electronic supplementary material

The online version of this article (doi:10.1186/s13000-017-0642-3) contains supplementary material, which is available to authorized users.

Growth charts for Australian children with achondroplasia

Achondroplasia is an autosomal dominant disorder, the most common genetic cause of short stature in humans. Reference curves for head circumference, weight, height, and BMI are needed in clinical practice but none exist for the Australian population. This study aimed to produce head circumference, height, weight, and BMI reference percentile curves for Australian children and adolescents with achondroplasia. Measurements of head circumference, height and weight taken at clinical visits were retrospectively extracted from the electronic medical record. Age was corrected for prematurity. Patients were excluded from head circumference analysis if they had significant neurosurgical complications and from the weight and BMI analysis when they had a clinical diagnosis of overweight. Measurements were available on 138 individuals (69 males and 69 females) taken between 1970 and 2015, with over 50% collected since 2005. A total of 3,352 data points were available. The LMS method was used to produce growth charts with estimated centiles (10, 25, 50, 75, and 90th) separately for males and females. For females birth weight was 3 kg (2.5-3.5 kg), birth length 48 cm (44-50 cm) and head circumference 37.5 cm (36-39 cm), adult height was 125 cm (116-132 cm), weight 42 kg (34-54 kg), and head circumference 58 cm (55.5-60.5 cm) all 50th centile (10-90th). For males birth weight was 3.5 kg (3-4 kg), length 49 cm (46-52 cm) and head circumference 38.5 cm (36-41 cm), adult height was 134 cm (125-141 cm), weight 41 kg (24.5-57 kg) and head circumference 61 cm (58-64 cm). The curves are similar to previously published reference data from the USA and have expected population wide variation from curves from an Argentinian population. Despite limitations of our curves for adolescents (12 years and older) due to data paucity, these Australian growth charts for children and adolescents with achondroplasia will be a useful reference in clinical practice.

Arthroscopic knee anatomy in young achondroplasia patients

PURPOSE

Achondroplasia is the most common form of skeletal dysplasia, affecting more than 250 000 individuals worldwide. In these patients, the developing knee undergoes multiple anatomical changes. The purpose of this study was to characterise the intra-articular knee anatomy in children with achondroplasia who underwent knee arthroscopy.

METHODS

Records of achondroplasia patients who underwent knee arthroscopy between 2009 and 2014 were reviewed. Demographic data, operative reports, follow-up notes, MRI and arthroscopy images were reviewed. Bony, cartilaginous and ligamentous changes were noted. The trochlea sulcus angle was measured from intra-operative arthroscopic images.

RESULTS

A total of 12 knee arthroscopies in nine patients were performed. The mean age at surgery was 16.9 years (12 to 22). In all patients, the indication for surgery was knee pain and/or mechanical symptoms that were refractory to non-operative treatment. Three anatomical variations involving the distal femur were found in all knees: a deep femoral trochlea; a high A-shaped intercondylar notch; and a vertically oriented anterior cruciate ligament. The average trochlea sulcus angle measured 123°. Pathology included: synovial plica (one knee); chondral lesions (three knees); discoid lateral meniscus (11 knees); and meniscal tears (six knees). All patients were pain-free and returned to normal activity at final follow-up.

CONCLUSION

Children with achondroplasia have characteristic distal femur anatomy noted during knee arthroscopy. These variations should be considered normal during knee arthroscopy in these patients. Arthroscopic findings confirmed previous MRI findings within this specific population with the addition of a deep trochlear groove which was not previously reported.

Abnormal pelvic morphology and high cervical length are responsible for high-risk pregnancies in women displaying achondroplasia

Pregnancies of women displaying achondroplasia are at high risk of adverse events. Early sonographic assessment of affected women can indicate an unusually long cervical length. It is the consequence of pathological anatomy of the pelvis. Thus, there is a foreseeable dystocia owing to cephalopelvic disproportion. Furthermore, this situation could also complicate cervical ripening prior to fetal extraction.

Achondroplasia and limb lengthening: Results in a UK cohort and review of the literature

AIMS

We aim to review the results, complications and outcomes of a single surgeon's series of lower limb lengthening in patients with achondroplasia.

METHODS

Ten achondroplastic children underwent limb lengthening. The patients, medical records and radiographs were reviewed.

RESULTS

The average age at the time of the index operation was 7.8 years. A single surgeon undertook all procedures. The average total length gain was 20.5 cm. The commonest complication was a fractured femur after removal of the frame.

CONCLUSION

Although complication rates were high (70%), none were left with any long-term sequelae and all were pleased with the results.

Lateral retroperitoneal transpsoas interbody fusion in a patient with achondroplastic dwarfism

The authors present the first reported use of the lateral retroperitoneal transpsoas approach for interbody arthrodesis in a patient with achondroplastic dwarfism. The inherent anatomical abnormalities of the spine present in achondroplastic dwarfism predispose these patients to an increased incidence of spinal deformity as well as neurogenic claudication and potential radicular symptoms. The risks associated with prolonged general anesthesia and intolerance of significant blood loss in these patients makes them ideal candidates for minimally invasive spinal surgery. The patient in this case was a 51-year-old man with achondroplastic dwarfism who had a history of progressive claudication and radicular pain despite previous extensive lumbar laminectomies. The lateral retroperitoneal transpsoas approach was used for placement of interbody cages at L1/2, L2/3, L3/4, and L4/5, followed by posterior decompression and pedicle screw instrumentation. The patient tolerated the procedure well with no complications. Postoperatively his claudicatory and radicular symptoms resolved and a CT scan revealed solid arthrodesis with no periimplant lucencies.

Optimal management of complications associated with achondroplasia

Achondroplasia is the most common form of skeletal dysplasia, resulting in disproportionate short stature, and affects over 250,000 people worldwide. Individuals with achondroplasia demonstrate a number of well-recognized anatomical features that impact on growth and development, with a complex array of medical issues that are best managed through a multidisciplinary team approach. The complexity of this presentation, whereby individual impairments may impact upon multiple activity and participation areas, requires consideration and discussion under a broad framework to gain a more thorough understanding of the experience of this condition for individuals with achondroplasia. This paper examines the general literature and research evidence on the medical and health aspects of individuals with achondroplasia and presents a pictorial model of achondroplasia based on The International Classification of Functioning, Disability, and Health (ICF). An expanded model of the ICF will be used to review and present the current literature pertaining to the musculoskeletal, neurological, cardiorespiratory, and ear, nose, and throat impairments and complications across the lifespan, with discussion on the impact of these impairments upon activity and participation performance. Further research is required to fully identify factors influencing participation and to help develop strategies to address these factors.

Advances in research on and diagnosis and treatment of achondroplasia in China

Achondroplasia is a rare autosomal dominant genetic disease. Research on achondroplasia in China, however, has received little emphasis. Around 80-90% of cases of neonatal achondroplasia result from mutations in fibroblast growth factor receptor 3 (FGFR3) according to polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). Recently, genetic research on achondroplasia in China made a major breakthrough by revealing two novel mutations located on the FGFR3 gene, thus helping to complete the pathological molecular map of achondroplasia. There are still, however, unknown aspects of the diagnosis and treatment of achondroplasia. This review will summarize advances in research on and the clinical diagnosis and treatment of achondroplasia in China.

Otolaryngologic manifestations of skeletal dysplasias in children

This article reviews some of the otolaryngologic manifestations of skeletal dysplasias. Achondroplasia is discussed most comprehensively. Skeletal dysplasias are bone and cartilage disorders that disrupt the development of the long bones, craniofacial skeleton, and vertebral column, with the most notable characteristic being short stature. Children with skeletal dysplasias have various medical problems. These children often develop head and neck manifestations of their disorders. Hearing loss, middle ear disease, and respiratory difficulties are seen in these children. Otolaryngologists must be knowledgeable about these disorders to diagnose, treat, and appropriately refer children with skeletal dysplasias.

Is bilateral lower limb lengthening appropriate for achondroplasia?: midterm analysis of the complications and quality of life

BACKGROUND

Use of the Ilizarov technique for limb lengthening in patients with achondroplasia is controversial, with a high risk of complications balancing cosmetic gains. Although several articles have described the complications of this procedure and satisfaction of patients after surgery, it remains unclear whether lengthening improves the quality of life (QOL) of these patients.

QUESTIONS/PURPOSES

We asked whether bilateral lower limb lengthenings with deformity correction in patients with achondroplasia would improve QOL and investigated the correlation between complication rate and QOL.

PATIENTS AND METHODS

We retrospectively reviewed 22 patients (average age, 12.7 years) diagnosed with achondroplasia who underwent bilateral lower limb lengthenings between 2002 and 2005. These patients were compared with 22 patients with achondroplasia for whom limb lengthening was not performed. The two groups were assessed using the American Academy of Orthopaedic Surgeons (AAOS) lower limb, SF-36, and Rosenberg self-esteem scores. Minimum followup was 4.5 years (range, 4.5-6.9 years).

RESULTS

Among the lengthening group, the average gain in length was 10.21 ± 2.39 cm for the femur and 9.13 ± 2.12 cm for the tibia. A total of 123 complications occurred in these 88 segments. The surgical group had higher Rosenberg self-esteem scores than the nonsurgical group although there were no differences in the AAOS and the SF-36 scores. The self-esteem scores decreased with the increase in the number of complications.

CONCLUSIONS

Our data suggest that despite frequent complications, bilateral lower limb lengthening increases patients' QOL. We believe lengthening is a reasonable option in selected patients.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Endoscopic third ventriculostomy in hydrocephalus associated with achondroplasia

Hydrocephalus in patients with achondroplasia is thought to be due to increased dural sinus venous pressure resulting from narrowing of the jugular foramen. In this setting, where hydrocephalus is presumed to be "vascular" in origin and therefore communicating, endoscopic third ventriculostomy (ETV) would seem contraindicated. The authors describe 3 patients in whom ETV was successfully performed, resulting in MR imaging-documented decreases in ventricle size. The patients were 11 months, 33 months, and 13 years at the time of surgery. All patients had serial preoperative MR images demonstrating progressive hydrocephalus in a "triventricular" pattern with a small fourth ventricle but an open aqueduct. All patients had undergone suboccipital decompression for foramen magnum stenosis prior to the treatment of hydrocephalus. Preoperative retrograde venography revealed variable pressure gradients across the jugular foramen. It is postulated that the increase in intracranial venous pressure resulting from jugular foramen stenosis may lead to disproportionate venous engorgement of the cerebellum and some degree of obstructive hydrocephalus amenable to ETV. The authors discuss the role of suboccipital decompression in the progression of hydrocephalus in patients with achondroplasia.

Analysis of sagittal spinopelvic parameters in achondroplasia

STUDY DESIGN

Prospective radiological analysis of patients with achondroplasia.

OBJECTIVE

To analyze sagittal spinal alignment and pelvic orientation in achondroplasia patients.

SUMMARY OF BACKGROUND DATA

Knowledge of sagittal spinopelvic parameters is important for the treatment of achondroplasia, because they differ from those of the normal population and can induce pain.

METHODS

The study and control groups were composed of 32 achondroplasia patients and 24 healthy volunteers, respectively. All underwent lateral radiography of the whole spine including hip joints. The radiographic parameters examined were sacral slope (SS), pelvic tilt, pelvic incidence (PI), S1 overhang, thoracic kyphosis, T10-L2 kyphosis, lumbar lordosis (LL1, LL2), and sagittal balance. Statistical analysis was performed to identify significant differences between the two groups. In addition, correlations between parameters and symptoms were sought.

RESULTS

Sagittal spinopelvic parameters, namely, pelvic tilt, pelvic incidence, S1 overhang, thoracic kyphosis, T10-L2 kyphosis, lumbar lordosis 1 and sagittal balance were found to be significantly different in the patient and control groups (P < 0.05). In addition, sagittal parameters were found to be related to each other in the patient group (P < 0.05), that is, PI was related to SS and pelvic tilt, and LL was related to thoracic kyphosis. Furthermore, in terms of relations between spinal and pelvic parameters, LL was related to SS and PI, and sagittal balance was related to SS and PI. Furthermore, LL and T10-L2 kyphosis were found to be related to pain (P < 0.05), whereas no other parameter was found to be related to VAS scores.

CONCLUSION

Sagittal parameters and possible relationships between sagittal parameters and symptoms were found to be significantly different in achondroplasia patients and normal healthy controls. The present study shows that sagittal spinal and pelvic parameters can assist the treatment of spinal disorders in achondroplasia patients.

Surgical management of pelvic organ prolapse in a woman with achondroplasia

BACKGROUND

Achondroplasia is an autosomal-dominant disorder resulting in short-limbed dwarfism. Limited data exist regarding the management of pelvic organ prolapse in women with achondroplasia.

CASE

A young nulligravid woman with stage IV uterovaginal prolapse desired surgical correction of her prolapse with uterine preservation. The severity of her prolapse, profound cervical elongation, and distortion of the bony pelvis presented surgical challenges. She underwent abdominal lumbohysteropexy with polypropylene mesh. At 1 year postoperative, she has marked improvement in symptoms and objective findings.

CONCLUSION

Abdominal lumbohysteropexy appears to be an effective surgical approach in women with achondroplasia desiring uterine preservation.

Achondroplasia and cervical laminoplasty

Achondroplasia is associated with short pedicles that predispose individuals with this trait to develop symptomatic spinal canal stenosis. Laminoplasty is an excellent means of treating cervical myelopathy due to stenosis in selected individuals. Laminoplasty preserves segmental motion and stability, both of which are of benefit to all individuals. The authors report the successful surgical treatment of an achondroplastic adult woman with laminoplasty. This procedure alleviated her symptoms, and she was doing well at 2-year follow-up.

Sleep-related respiratory abnormalities and arousal pattern in achondroplasia during early infancy

OBJECTIVE

To assess sleep-disordered breathing (SDB), sleep architecture, and arousal pattern in infants with achondroplasia and to evaluate the relationship between foramen magnum size and the severity of SDB.

STUDY DESIGN

A retrospective review of polysomnographic recordings and medical records was performed in infants with achondroplasia and in aged-matched control subjects. All studies were re-scored with the emphasis on respiratory events, sleep state, and arousals. In addition, the neuroimaging study of the brain (magnetic resonance imaging) was reviewed to evaluate foramen magnum diameters and to assess their relationship to SDB.

RESULTS

Twenty-four infants met the criteria for entry into analysis, 12 infants with achondroplasia (A) and 12 control infants (C). There was no significant difference in age or sex. Infants with achondroplasia had a significant increase in total respiratory disturbance index (RDI; A, 13.9 +/- 10.8 versus C, 2.0 +/- 0.9; P < .05). However, there was no significant difference in percentages of active sleep, quiet sleep, or sleep efficiency. Analysis of arousals demonstrated that infants with achondroplasia had a significant decrease in both spontaneous arousal index (A, 10.5 +/- 3.5/hr versus C, 18.6 +/- 2.7; P < .0001) and respiratory arousals (A, 10.3% +/- 6.3% versus C, 27.5 +/- 9.5%; P < .0001). Evaluation of foramen magnum dimensions demonstrated smaller foramen magnum size, but there were no significant correlations between anteroposterior or transverse diameters and RDI.

CONCLUSION

Infants with achondroplasia have significant SDB during early infancy. SDB in infants with achondroplasia is not associated with alteration in sleep architecture, possibly because of attenuation of the arousal response. We speculate that the concomitant increased apneic events and decreased arousal response will lead to vulnerability in these infants and may underlie the pathophysiologic mechanism of sudden unexpected death in this population.

Lumbar fusion in achondroplasia: does fusion to the sacrum affect function?

BACKGROUND

Stenosis and kyphosis are common in achondroplasia, often requiring lumbar fusion, sometimes to the sacrum. The purpose of this study was to determine the functional effect of lumbar fusion to the sacrum in patients with achondroplasia.

METHODS

Functional and SF-36 questionnaires were sent to the 66 patients with achondroplasia who underwent instrumented lumbar fusion at our institution from 1991 to 2006. Of the 35 who returned questionnaires, 13 had fusions to the sacrum and 22 did not. Chi-square analysis and a t test were used to evaluate outcomes. Significance was set at P<0.05 or a 95% confidence interval that did not cross 1.

RESULTS

There were no statistical differences in SF-36 scores. There was a trend toward more pain in the group fused to the sacrum (P=0.1). There were no statistically significant differences in difficulty with activities, but there was a trend toward increased difficulty with hygiene after toileting in the group with fusion to the sacrum (odds ratio: 3.76, confidence interval: 0.53-26.87, P=0.19).

CONCLUSIONS

Fusion to the sacrum did not significantly affect function in patients with achondroplasia, although there was a trend toward increased pain and greater difficulty with hygiene after toileting.

Achondroplasia

Achondroplasia (MIM 100800) is the most common non-lethal skeletal dysplasia. Its incidence is between one in 10,000 and one in 30,000. The phenotype is characterized by rhizomelic disproportionate short stature, enlarged head, midface hypoplasia, short hands and lordotic lumbar spine, associated with normal cognitive development. This autosomal-dominant disorder is caused by a gain-of-function mutation in the gene encoding the type 3 receptor for fibroblast growth factor (FGFR3); in more than 95% of cases, the mutation is G380R. The diagnosis is suspected on physical examination and confirmed by different age-related radiological features. Anticipatory and management care by a multidisciplinary team will prevent and treat complications, including cervical cord compression, conductive hearing loss and thoracolumbar gibbosity. Weight counselling, psychosocial guidance and professional integration programmes play an important role in the global quality of life of these patients and their families.