FormalPara Key Summary Points

Achondroplasia is a lifelong condition requiring lifelong management.

Many people are lost to follow-up after the transition from paediatric to adult care, and there is no standardised approach for management in adults.

The European Achondroplasia Forum (EAF) (www.achondroplasiaforum.com) has developed a patient-held checklist to support adults with achondroplasia in managing their health.

The EAF checklist provides key symptoms to be aware of, including action points, and is intended to guide consultations and discussions and to support and empower people with achondroplasia to manage their own health.

The EAF propose that the checklist be delivered to young people with achondroplasia during the transition from paediatric to adult care.

Introduction

Achondroplasia is a lifelong condition requiring lifelong management [1, 2]. In many countries, care is fairly well organised for infants and children with this condition, with international consensus recommendations emphasising the benefits of multidisciplinary management in expert centres [1,2,3]. Close monitoring during the first 2–3 years of life is critical [1,2,3,4]. Follow-up after transition from paediatric services can be more complicated, but remains essential, since adults with achondroplasia are at risk of medical complications impacting physical functioning and daily activities [5]. Until recently, understanding of complications of achondroplasia in adulthood has been relatively lacking, but data from natural history studies such as CLARITY, LIAISE, and The Norwegian Adult Achondroplasia study, as well as recently published review papers, have improved our understanding of the key issues affecting people with achondroplasia as they age [5,6,7,8,9,10,11,12,13,14].

Although some recommendations for care of adults with achondroplasia do exist [1,2,3], they are not as extensive and specific as those for children. Both the International Consensus Statement and The European Achondroplasia Forum (EAF) Guiding Principles acknowledge that the condition requires lifelong management by an experienced multidisciplinary team, with regular monitoring after transition to adult care—including counselling on genetics, pregnancy, and psychosocial well-being [1, 2].

However, an online survey conducted by the EAF identified that barriers to effective care in adults exist. These include that there is often no multidisciplinary service available for adults with achondroplasia, those services that do exist are not as experienced as their paediatric counterparts, and there could be a lack of interest or resistance from individuals with achondroplasia to seek ongoing care [15]. Often, people with achondroplasia are relatively healthy at the point of transition from paediatric to adult care; they may therefore feel there is no need to continue accessing regular medical care as a young adult [15]. Therefore, many people are lost to follow-up at the point of transitioning to adult services [15].

Transfer from paediatric to adult healthcare is a particularly vulnerable period for people with chronic conditions [16]. Many factors are associated with being lost to follow-up—some patient- or disease-related, others linked to the healthcare system [17]. In more common conditions, such as type 1 diabetes and inflammatory bowel disease, the experience is that the period of transition is challenging, and people are lost to follow-up [18,19,20]. Despite the importance of long-term care and monitoring, many people with a chronic condition fail to adhere to follow-up [17, 21, 22].

Taken together, the healthcare risks and lack of a standardised approach suggest there is a clear need for proactive adult care in achondroplasia. The key issue remains how to implement this.

From Paediatric Multidisciplinary Team to Primary Care Services

The well-established paediatric multidisciplinary care model is not replicated for adults with achondroplasia, who often find themselves under the management of their primary care provider. This is also the case for many other chronic conditions being managed in primary care, with specialist referrals as needed. Relying on the partnership between the patient and their primary care provider requires that both parties are well educated and informed about achondroplasia, including the range of potential complications through the lifespan, and that they have a directory of specialists available should red-flag symptoms arise. With over 7000 rare disorders identified, it is impossible for every primary care provider to be an expert across even a small fraction. It is estimated that the average primary care provider sees only one case of an individual rare disease in their career [23]. Naturally, it is not realistic to expect the primary care provider to be up to date on international guidelines and recommendations on rare conditions [23]. There is a need for a mechanism to disseminate core information to those in primary care who encounter an individual with a rare condition, and often the individuals themselves are the best people to do this. Some people with achondroplasia are experts on their condition by experience, but at the other end of the spectrum some may struggle with the confidence and health literacy to access the healthcare they need as adults.

Patient-Held Checklist

Adults with achondroplasia may not need routine clinic appointments when they are well, but individuals must be clear on red flag symptoms of potentially severe complications of the condition and on what steps to take should these symptoms present. The idea of a standardised, patient-held checklist empowers individuals to take control of their own healthcare requirements. Patient-held tools have been shown to increase adherence to guideline-based care [24], to facilitate communication [25], and to assist in enhancing handover and patient-centred practices for people with chronic conditions such as cardiovascular disease, chronic respiratory disease, diabetes [26], and cancer [27].

To test the idea of a patient-held checklist in achondroplasia, the EAF developed a checklist that was presented and discussed during a workshop held in Frankfurt, Germany, in April 2023. The meeting was attended by 112 healthcare professionals, patient advocacy representatives, and individuals with achondroplasia from 19 countries.

The checklist is intended to raise awareness of red flag symptoms of potentially severe complications and to provide a framework for discussion during a routine appointment in the primary care setting. This document has been drafted by the EAF based on the most up-to-date guidelines and natural history information. This article is based on previously conducted studies and does not contain any new studies with human participants or animals performed by any of the authors.

The first two sections of the checklist are structured around two key complications: symptomatic spinal stenosis and obstructive sleep apnoea, both among the most frequent and potentially severe complications in adults with achondroplasia (Box 1 and Box 2). For each, a number of symptoms are detailed, with a suggested course of immediate action for both the patient and primary care provider (Fig. 1). By providing information on key symptoms, people with achondroplasia can be aware of when there is a need to see a healthcare professional.

Fig. 1
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The EAF patient-held checklist

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The checklist also includes information for routine follow-up in primary care on achondroplasia-specific considerations for blood pressure, pain, hearing, weight, discussing the need for aids and adaptations, as well as psychosocial aspects of care [2].

Blood Pressure

Hypertension appears to be more common in adults with achondroplasia and has been reported in approximately 50% of men and 35% of women compared to 22% in the general population [8, 46]. It is therefore essential to check blood pressure regularly, as untreated hypertension can lead to cardiovascular disease and increased mortality. Blood pressure measurement should be undertaken using a cuff that fits appropriately; measurement on the forearm is an option if elbow contractures or rhizomelia prevent measurement at the upper arm [2, 46].

Hearing Loss

Ear infections and hearing loss are common in children with achondroplasia, but recent evidence suggests the risks extend into adulthood [9]. Hearing loss affects around one in five people in the general population and has been ranked as the third largest cause of disability worldwide [47]. In a population-based study on adults with achondroplasia, 43% of people aged 16–44 had mild loss in at least one ear, with no real difference between men and women [9]. This more than doubled prevalence emphasises the need for regular hearing assessments, even in younger patients.

Lifestyle and Weight

Many adults with achondroplasia find it difficult to prevent weight gain [6, 48, 49]. Although the risk of develo** type 2 diabetes or metabolic complications does not seem to be increased in achondroplasia, obesity predisposes to sleep apnoea and hypertension, may worsen leg and back pain and spinal stenosis, and may cause reduced mobility and physical functioning [2, 5, 10, 29]. As for the general population, it is important to maintain a healthy diet and regular physical activity [6, 8, 46, 48, 50]. However, there is minimal evidence to guide nutritional management in this population, including how to classify obesity [51].

Pain and Function

Pain becomes more prevalent into adulthood [14]. In several studies, approximately 65–70% of adults with achondroplasia reported chronic pain [5, 14, 33, 52]. Pain can impact mood, self-care, education, employment, and leisure activities, and as such it is recommended that it is examined and monitored using patient-reported outcome scales such as the Brief Pain Inventory [2, 5, 33, 52, 53]. It is particularly important to identify pain related to early symptoms of spinal stenosis [2, 5]. The need for adaptations or aids to support everyday activities may change throughout the lifespan and should be discussed at every medical check-up [2]. This includes specific requirements or modifications at home, school, work, or in the community to promote independence and participation and ease everyday activities. For many people with short stature, a car is crucial to maintain independence.

Genetic Aspects

Achondroplasia is a genetic condition, caused by pathogenic missense variants in the gene coding for the fibroblast growth factor receptor 3 (FGFR3) [2]. The condition is transmitted in an autosomal dominant manner [2]. When one parent has achondroplasia, there is a 50% probability of each child receiving the FGFR3 variant and therefore having achondroplasia [2]. If both parents are affected, the probability for “classic” achondroplasia (heterozygous carrier) in each child is 50% and the probability for severe (perinatally lethal) achondroplasia (homozygous carrier) is 25%; there is still a 25% chance of having an unaffected child [2]. Many adults with achondroplasia seek information to understand their available reproductive options and possibilities for preimplantation and/or prenatal diagnosis. As noted in the recommendations, several different agencies can provide this support, but they differ from country to country [2]. Including this item in the routine follow-up checklist should help people to identify the most appropriate source of support in their location, to access prenatal advice and counselling.

Psychosocial Health

Achondroplasia presents psychosocial challenges across the lifespan [2]. Several studies demonstrate that adults with achondroplasia tend to have lower quality of life than the general population for both physical and mental domains [2, 33, 52,53,54,55]. Appropriate support, including through patient advocacy groups, should be made available and provided in a culturally sensitive way [2].

Each country or region should have well identified centres of expertise with experience in dealing with the above-mentioned complications, in particular spinal stenosis.

Implementation of Patient-Held Checklist in Clinical Practice

When considering whether a patient-held checklist could work in practice, a key advantage of this model is that there is no need for a fixed multidisciplinary team—only one lead healthcare provider in primary care, who is responsible for appropriate referrals to specialists with expertise in achondroplasia. This model is a good starting point and should be feasible to implement across different countries and healthcare systems. The checklist will support a systematic and structured way of monitoring people with achondroplasia without stigma or unnecessary medical burden. It is intended to guide consultations and discussions and to support and empower people to manage their own health. Primary care providers can ask for symptoms of spinal stenosis and sleep apnoea, including performing a formal pain assessment, to identify early symptoms or signs and initiate appropriate action and referrals as indicated in the checklist. Local healthcare providers are also well positioned to manage blood pressure, hearing issues and weight, and for these issues people with achondroplasia can be treated as for the general population.

Generally, there is no consensus on the need for a regular assessment in adults with achondroplasia. Some argue for starting routine assessments at a particular age, with more frequent annual or biannual assessments as people get older. Others believe healthcare should be on demand and accessed only as and when an individual has a concern, as for people in the general population. One thing that is clear is that any assessment model or checklist implementation should be on an opt-in basis rather than something perceived as mandatory. As in any condition or population of people, there is a spectrum of behaviour, beliefs, and desires. In this regard, patient choice will be important.

Process for Transition from Paediatric to Adult Care

The existing paediatric care model is based on the different complications that may occur in children with achondroplasia, with dedicated multidisciplinary clinics set up around key affected systems and supported by specialists in areas such as neurosurgery, orthopaedic and spine surgery, ear, nose, and throat (ENT) and sleep-disordered breathing, physical functioning and daily activities, and psychosocial well-being. Transition out of paediatric care should therefore prepare young people for the adult setting, where the multidisciplinary team might not exist and the primary care physician provides the management and follow-up. This is the case in other chronic conditions. For example, in the UK, transfer from paediatric to adult care in patients with diabetes takes place at 17–18 years of age, but the preparation for transition begins from the age of 14 years, with increasingly autonomous care more focused on the individual than the family [56]. Similarly, in paediatric inflammatory bowel disease, there is an iterative process that starts at the age of 11 years, with regular health maintenance visits every 1–2 years that prepares children for the transition to adult gastroenterology [20]. Other suggested models include a handover clinic with a one-off direct transfer, parallel adult and paediatric clinics that allow for communication between physicians, or transition clinics where adolescent patients are seen by both teams [57]. Ultimately, a good transition should result in a handover of power from parents to the individual, with increasing levels of engagement and delegation that support them to own and manage their condition in early adulthood. In achondroplasia, transition should happen in mid to late childhood, with specific considerations and emphasis placed on spinal stenosis and sleep-disordered breathing, as well as pain management, weight, and mental health. There may be a place for some baseline investigations at the point of transition, including MRI of the spine and a sleep study, which can both be used for comparison in later years, if needed. This approach has been trialled in clinics in the US, where it has proven useful to support clinical decision-making for people who are lost to follow-up after paediatric care but present many years later with a symptom.

Discussion

Achondroplasia is a lifelong condition with associated lifelong medical complications that can have significant impact on physical functioning, daily activities, pain, and psychosocial health. Adults with achondroplasia have been found to have lower physical and psychosocial health than people without, alongside higher rates of anxiety, depression, and low self-esteem [5, 12, 54, 55]. This demonstrates the need for lifelong care [1, 2], but how that care is delivered is vital. Achondroplasia does not necessarily require regular, routine check-ups if people are feeling well. However, empowering people with achondroplasia to understand their condition and recognise key symptoms and red flags can help to direct resources and ensure timely referrals to specialists. International consensus guidelines already exist [2], but a need remains to implement these in clinical practice. It has previously been suggested that the unique characteristics of people with a rare condition demand evolution beyond the multidisciplinary model to a more nuanced one of networked care, based on the experience and expertise of the relevant community [23].

Alongside development of the EAF checklist, we have made some suggestions for how to move people from paediatric to adult care to help avoid the common pitfall of being lost to follow-up, a common occurrence for people with chronic conditions in this period of their life [16, 18, 19]. This will become a key consideration in supporting people with achondroplasia to optimise their health and make the most of the healthcare support available, should they need or desire it. Transition could also represent the optimal moment at which to deliver the proposed checklist—when individuals are learning to engage with their condition and taking more responsibility from their parents and carers about how to manage it.

The checklist is available on the EAF website (achondroplasiaforum.com). Where appropriate, the checklist could be made available on an app, both making it accessible to younger people and enabling easy updates to account for evolving data, literature, and recommendations. However, a key point to consider in planning for transition from paediatric services is that adolescence and early adulthood is the point in the lifespan when people have the fewest achondroplasia complications [12] and therefore feel comparatively well. With this in mind, any initiative to implement follow-up for adults with achondroplasia needs to be meaningful; otherwise, it will be susceptible to the poor adherence seen in other chronic conditions.

Conclusion

The EAF advocates the development of a patient-held checklist to support adult follow-up through the lifespan. The checklist should be delivered to young people with achondroplasia during the transition from paediatric to adult care as part of an endeavour to empower them to understand their condition, recognise key symptoms and red flags, and direct resources and ensure timely referrals to specialists. Each country or region should have well-identified centres of expertise with experience in dealing with the mentioned complications, in particular spinal stenosis. It is important to communicate the benefits of proactive management of any symptoms that may arise and that individuals are confident about working with their primary care provider for their ongoing health and well-being into adulthood.