Achondroplasia Natural History Study (CLARITY): 60-year experience with hydrocephalus in achondroplasia from four skeletal dysplasia centers.

OBJECTIVE: The objective of this study was to describe the incidence and management of hydrocephalus in patients with achondroplasia over a 60-year period at four skeletal dysplasia centers. METHODS: The Achondroplasia Natural History Study (CLARITY) is a registry for clinical data from achondroplasia patients receiving treatment at four skeletal dysplasia centers in the US from 1957 to 2017. Data were entered and stored in a REDCap database and included surgeries with indications and complications, medical diagnoses, and radiographic information. RESULTS: A total of 1374 patients with achondroplasia were included in this study. Of these, 123 (9%) patients underwent treatment of hydrocephalus at a median age of 14.4 months. There was considerable variation in the percentage of patients treated for hydrocephalus by center and decade of birth, ranging from 0% to 28%, although in the most recent decade, all centers treated less than 6% of their patients, with an average of 2.9% across all centers. Undergoing a cervicomedullary decompression (CMD) was a strong predictor for treatment of hydrocephalus (OR 5.8, 95% CI 3.9-8.4), although that association has disappeared in those born since 2010 (OR 1.1, 95% CI 0.2-5.7). In patients born since 1990, treatment of hydrocephalus with endoscopic third ventriculostomy (ETV) has become more common; it was used as the first line of treatment in 38% of patients in the most recent decade. Kaplan-Meier analysis suggests that a single ETV will treat hydrocephalus in roughly half of these patients. CONCLUSIONS: While many children with achondroplasia have features of hydrocephalus with enlarged intracranial CSF spaces and relative macrocephaly, treatment of hydrocephalus in achondroplasia patients has become relatively uncommon in the last 20 years. Historically, there was a significant association between symptomatic foramen magnum stenosis and treatment of hydrocephalus, although concurrent treatment of both has fallen out of favor with the recognition that CMD alone will treat hydrocephalus in some patients. Despite good experimental data demonstrating that hydrocephalus in achondroplasia is best understood as communicating in nature, ETV appears to be reasonably successful in certain patients and should be considered an option in selected patients.

Achondroplasia natural history study (CLARITY): 60-year experience in orthopedic surgery from four skeletal dysplasia centers.

BACKGROUND: The purpose of this study was to describe the frequency and risk factors for orthopedic surgery in patients with achondroplasia. CLARITY (The Achondroplasia Natural History Study) includes clinical data from achondroplasia patients receiving treatment at four skeletal dysplasia centers in the United States from 1957 to 2018. Data were entered and stored in a Research Electronic Data Capture (REDCap) database. RESULTS: Information from one thousand three hundred and seventy-four patients with achondroplasia were included in this study. Four hundred and eight (29.7%) patients had at least one orthopedic surgery during their lifetime and 299 (21.8%) patients underwent multiple procedures. 12.7% (n = 175) of patients underwent spine surgery at a mean age at first surgery of 22.4 ± 15.3 years old. The median age was 16.7 years old (0.1-67.4). 21.2% (n = 291) of patients underwent lower extremity surgery at a mean age at first surgery of 9.9 ± 8.3 years old with a median age of 8.2 years (0.2-57.8). The most common spinal procedure was decompression (152 patients underwent 271 laminectomy procedures), while the most common lower extremity procedure was osteotomy (200 patients underwent 434 procedures). Fifty-eight (4.2%) patients had both a spine and lower extremity surgery. Specific risk factors increasing the likelihood of orthopedic surgery included: patients with hydrocephalus requiring shunt placement having higher odds of undergoing spine surgery (OR 1.97, 95% CI 1.14-3.26); patients having a cervicomedullary decompression also had higher odds of undergoing spine surgery (OR 1.85, 95% CI 1.30-2.63); and having lower extremity surgery increased the odds of spine surgery (OR 2.05, 95% CI 1.45-2.90). CONCLUSIONS: Orthopedic surgery was a common occurrence in achondroplasia with 29.7% of patients undergoing at least one orthopedic procedure. Spine surgery (12.7%) was less common and occurred at a later age than lower extremity surgery (21.2%). Cervicomedullary decompression and hydrocephalus with shunt placement were associated with an increased risk for spine surgery. The results from CLARITY, the largest natural history study of achondroplasia, should aid clinicians in counseling patients and families about orthopedic surgery.

Otolaryngology Utilization in Patients With Achondroplasia: Results From the CLARITY Study.

OBJECTIVES/HYPOTHESIS: To quantify otolaryngologic surgery utilization in patients with achondroplasia, and to identify any changes in utilization over the past four decades. STUDY DESIGN: Retrospective cohort study. METHODS: A retrospective cohort study of 1,374 patients with achondroplasia enrolled in the CLARITY retrospective cohort study at four centers of multi-specialty care for patients with achondroplasia. Otolaryngologic surgeries are presented by birth cohort decade. The main outcomes were number of primary and additional otolaryngologic procedures; age at surgery; likelihood of repeated surgery; temporal trends in surgical utilization. RESULTS: In this cohort of 1,374 patients with achondroplasia, 620 (45.1%) had pharyngeal surgery at least once, 150 (10.9%) had pharyngeal surgery on more than one occasion, and patients who had adenoidectomy first were 2.68 times more likely to require a second pharyngeal surgery than those who had adenotonsillectomy. Seven hundred and seventy-nine (56.7%) had tympanostomy tubes placed at least once, and 447 (32.5%) had tympanostomy tubes placed more than one time. Age at first pharyngeal surgery decreased by 1.2 years per birth cohort decade, and age at tympanostomy tube placement decreased by 1.1 years per decade. CONCLUSIONS: Patients with achondroplasia often require otolaryngologic surgery, particularly adenoidectomy and/or tonsillectomy as well as tympanostomy tube placement. Such surgery is performed now more frequently and at younger ages than in earlier decades. While otolaryngologic disease associated with achondroplasia is now recognized earlier and treated more frequently, long-term outcome studies are needed. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:1548-1554, 2022.

Achondroplasia Natural History Study (CLARITY): 60-year experience in cervicomedullary decompression in achondroplasia from four skeletal dysplasia centers.

OBJECTIVE: The authors sought to determine the overall incidence of cervicomedullary decompression (CMD) in patients with achondroplasia and the characteristics associated with those surgeries across multiple institutions with experience caring for individuals with skeletal dysplasias. METHODS: Data from CLARITY (Achondroplasia Natural History Study) for 1374 patients with achondroplasia from four skeletal dysplasia centers (A. I. duPont Hospital for Children, Johns Hopkins University, University of Texas Health, and University of Wisconsin School of Medicine and Public Health) followed from 1957 to 2017 were recorded in a Research Electronic Data Capture (REDCap) database. Data collected and analyzed included surgeries, indications, complications, ages at time of procedures, screening procedures, and medical diagnoses. RESULTS: There were 314 CMD procedures in 281 patients (20.5% of the entire cohort). The median age of first CMD was 1.3 years in males and 1.1 years in females. Over time, there was a decrease in the median age of patients at first CMD. All patients born before 1980 who underwent CMD had the procedure after 5 years of age, whereas 98% of patients born after 2010 underwent CMD before 5 years of age. In addition, a greater proportion of patients born in more recent decades had documented neuroimaging and polysomnography (PSG) prior to CMD. Ventriculoperitoneal shunts (VPSs) were placed more frequently in patients undergoing CMD (23%) than in the entire cohort (8%). Patients who required either CMD or VPS were 7 times more likely to require both surgeries than patients who required neither surgery (OR 7.0, 95% CI 4.66-10.53; p < 0.0001). Overall, 10.3% of patients who underwent CMD required a subsequent CMD. CONCLUSIONS: The prevalence of CMD in this large achondroplasia cohort was 20%, with more recently treated patients undergoing first CMD at younger ages than earlier patients. The use of neuroimaging and PSG screening modalities increased over time, suggesting that increased and better surveillance contributed to earlier identification and intervention in patients with cervicomedullary stenosis and its complications.

Achondroplasia Natural History Study (CLARITY): a multicenter retrospective cohort study of achondroplasia in the United States.

PURPOSE: Achondroplasia is the most common short stature skeletal dysplasia (1:20,000-30,000), but the risk of adverse health outcomes from cardiovascular diseases, pain, poor function, excess weight, and sleep apnea is unclear. A multicenter retrospective natural history study was conducted to understand medical and surgical practices in achondroplasia. METHODS: Data from patients with achondroplasia evaluated by clinical geneticists at Johns Hopkins University, A.I. duPont Hospital for Children, McGovern Medical School UTHealth, and University of Wisconsin were populated into a REDCap database. All available retrospective medical records of anthropometry (length/height, weight, occipitofrontal circumference), surgery, polysomnography (PSG), and imaging (e.g., X-ray, magnetic resonance imaging) were included. RESULTS: Data from 1,374 patients (48.8% female; mean age 15.4 ± 13.9 years) constitute the primary achondroplasia cohort (PAC) with 496 subjects remaining clinically active and eligible for prospective studies. Within the PAC, 76.0% had a de novo FGFR3 pathologic variant and 1,094 (79.6%) had one or more achondroplasia-related surgeries. There are ≥37,000 anthropometry values, 1,631 PSGs and 10,727 imaging studies. CONCLUSION: This is the largest multicenter achondroplasia natural history study, providing a vast array of medical information for use in caring for these patients. This well-phenotyped cohort is a reference population against which future medical and surgical interventions can be compared.

CLARITY: Co-occurrences in achondroplasia-craniosynostosis, seizures, and decreased risk of diabetes mellitus.

Achondroplasia is the most common disproportionate short statured skeletal dysplasia with a prevalence of approximately 1:20,000-30,000. We created the largest database to date of a historical cohort of 1374 patients with achondroplasia (CLARITY-aChondropLasia nAtuRal hIsTory studY). This cohort was queried for the presence of unrecognized or under-recognized features associated with achondroplasia. Craniosynostosis was found to co-occur with achondroplasia in 9 (0.65%) patients in this cohort, which is much higher than the general population prevalence of 3.1-7.2 per 10,000. In addition, 27 patients had seizures (2.0%), an apparent excess as compared to the general population. Only two people had diabetes despite a high rate of adult obesity. This report documents for the first time an increased prevalence of craniosynostosis in persons with achondroplasia, and adds support to previous observations of an apparently higher than expected prevalence of seizures and lower prevalence of diabetes mellitus.