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

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Background Achondroplasia is the most common genetic skeletal disorder causing disproportionate short stature/dwarfism. Common additional features include spinal stenosis, midface retrusion, macrocephaly and a generalized spondylometaphyseal dysplasia which manifest as spinal cord compression, sleep disordered breathing, delayed motor skill acquisition and genu varus with musculoskeletal pain. To better understand the interactions and health outcomes of these potential complications, we embarked on a multi-center, natural history study entitled CLARITY (achondroplasia natural history study). One of the CLARITY objectives was to develop growth curves (length/height, weight, head circumference, weight-for-height) and corresponding reference tables of mean and standard deviations at 1 month increments from birth through 18 years for clinical use and research for achondroplasia patients. Methods All available retrospective anthropometry data including length/height, weight and head circumference from achondroplasia patients were collected at 4 US skeletal dysplasia centers (Johns Hopkins University, AI DuPont Hospital for Children, McGovern Medical School University of Texas Health, University of Wisconsin School of Medicine and Public Health). Weight-for-age values beyond 3 SD above the mean were excluded from the weight-for-height and weight-for-age curves to create a stricter tool for weight assessment in this population. Results Over 37,000 length/height, weight and head circumference measures from 1374 patients with achondroplasia from birth through 75 years of age were compiled in a REDCap database. Stature and weight data from birth through 18 years of age and head circumference from birth through 5 years of age were utilized to construct new length/height-for-age, weight-for-age, head circumference-for-age and weight-for-height curves. Conclusion Achondroplasia-specific growth curves are essential for clinical care of growing infants and children with this condition. In an effort to provide prescriptive, rather than purely descriptive, references for weight in this population, extreme weight values were omitted from the weight-for-age and weight-for-height curves. This well-phenotyped cohort may be studied with other global achondroplasia populations (e.g. Europe, Argentina, Australia, Japan) to gain further insight into environmental or ethnic influences on growth.

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Growth in achondroplasia including stature, weight, weight-for-height and head circumference from CLARITY: achondroplasia natural history study—a multi-center retrospective cohort study of achondroplasia in the US

Hoover‐Fong

Schulze

Alade

et al. 2021

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“…These causes are probably applicable to adults with achondroplasia as well. Impaired hearing might also get less attention in achondroplasia due to the high prevalence of other potential severe medical complications, as well as the daily challenges commonly experienced by persons with this condition [ 10 , 11 , 24 , 35 – 37 ].…”

Section: Discussionmentioning

confidence: 99%

Hearing loss in Norwegian adults with achondroplasia

Fredwall

Åberg

Berdal

et al. 2021

Background Achondroplasia is the most common form of disproportionate skeletal dysplasia. The condition is caused by a mutation in the FGFR3 gene, affecting endochondral bone growth, including the craniofacial anatomy. Recurrent otitis media infections, chronic middle ear effusion, and hearing loss are common in children with achondroplasia, but few studies have investigated hearing loss in adults with this condition. Objectives This population-based study investigated the prevalence, severity, and type of hearing loss in Norwegian adults with achondroplasia. Methods We collected data on 45 adults with genetically confirmed achondroplasia: 23 men and 22 women, aged 16–70 years. All participants underwent a comprehensive audiologic assessment, including medical history, pure-tone audiometry, speech audiometry, and impedance audiometry. According to the Global Burden of Disease classification, pure-tone average ≥ 20 decibel hearing level (dB HL) was considered clinically significant hearing loss. Results Insertion of ventilation tubes had been performed in 44% (20/45) of the participants, 49% (22/45) had a history of adenoidectomy, while 20% (9/45) used hearing aids. Hearing loss in at least one ear was found in 53% (24/45) of the participants; in 57% (13/23) of the men and 50% (11/22) of the women. In the youngest age group (age 16–44 years), 50% (14/28) had hearing loss, although predominantly mild (20–34 dB HL). An abnormal tympanometry (Type B or C) was found in 71% (32/45) of the participants. The majority (15/24) had conductive hearing loss, or a combination of conductive and sensorineural hearing loss (8/24). Conclusions Adults with achondroplasia are at increased risk of early hearing loss. Our findings underline the importance of a regular hearing assessment being part of standard care in achondroplasia, including adolescents and young adults. In adult patients diagnosed with hearing loss, an evaluation by an otolaryngologist should be considered, and the need for hearing aids, assistive listening devices, and workplace and educational accommodations should be discussed. Clinical trial registration ClinicalTrials.gov identifier NCT03780153.

“…The clinical features of achondroplasia can in turn lead to a developmental profile that differs from the norm, impaired self-care or ability to perform activities of daily living, reduced health-related quality of life (HRQoL), socioeconomic problems (e.g., reduced work participation), and early mortality [ 2 , 3 ]. The development of medical complications by age and their impact on different aspects of HRQoL are being investigated in natural history studies, such as the Lifetime Impact of Achondroplasia In Europe (LIAISE) study (clinicaltrials.gov NCT03449368) and the Achondroplasia Natural History Study (CLARITY) [ 4 ]. The medical complications of achondroplasia require lifelong multidisciplinary care, which varies with age [ 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

Literature review and expert opinion on the impact of achondroplasia on medical complications and health-related quality of life and expectations for long-term impact of vosoritide: a modified Delphi study

Savarirayan

Baratela

Butt

et al. 2022

Background Achondroplasia is associated with disproportionate short stature and significant and potentially severe medical complications. Vosoritide is the first medicine to treat the underlying cause of achondroplasia and data from phase 3 and phase 2 extension studies showed effects on growth and body proportions. However, there are currently no long-term data available on the direct impact on endpoints such as medical complications and health-related quality of life (HRQoL). This study explored the perceived impact of achondroplasia on medical complications, HRQoL, healthcare resource use and mortality, and potential modifying effects of vosoritide, based on published evidence and expert opinion. Structured expert opinion was obtained by an international modified Delphi study among 14 experts in managing achondroplasia performed on a virtual platform and consisting of an explorative phase followed by an anonymous individual rating round. Results Overall, the panelists expect that in individuals starting long-term treatment between 2 years of age and puberty, growth velocity increases observed in the clinical trials will be maintained until final height is reached (92% agreement) and will likely result in clinically meaningful improvements in upper-to-lower body segment ratio (85%). Earlier treatment initiation will likely result in a greater final height (100%) and more likely improve proportionality (92%) than later treatment. Although current data are limited, ≥ 75% of panelists find it conceivable that the earlier long-term treatment is started, the greater the probability of a positive effect on the lifetime incidence of symptomatic spinal stenosis, kyphosis, obstructive sleep apnea, and foramen magnum stenosis. These are among the most clinically important complications of achondroplasia because of their high impact on comorbidity, mortality, and/or HRQoL. A positive effect of vosoritide on the incidence of surgeries through lifetime was considered more likely with earlier long-term treatment (90%). Conclusions This explorative study, based on international expert opinion, provides further insight into the medical and functional impacts of achondroplasia and how these might be modified through long-term use of vosoritide. The results can be used to guide the direction and design of future research to validate the assumptions and to discuss potential treatment outcomes with disease modifying therapies with families and clinicians.