Correction to: High prevalence of symptomatic spinal stenosis in Norwegian adults with achondroplasia: a population-based study.

An amendment to this paper has been published and can be accessed via the original article.

High prevalence of symptomatic spinal stenosis in Norwegian adults with achondroplasia: a population-based study.

BACKGROUND: Symptomatic spinal stenosis (SSS) is a well-known medical complication in achondroplasia. The reported prevalence of SSS is 10 to 30%, an estimate based on small studies or selected populations. No population-based studies exist currently. Furthermore, the relationship between SSS and physical functioning has not been investigated in detail. The aims of this study were to describe the prevalence of SSS in Norwegian adults with achondroplasia, and to explore the impact of SSS on physical functioning. METHODS: This was a population-based study on Norwegian community-dwelling adults with genetically confirmed achondroplasia. Prevalence of SSS was defined by clinical symptoms, and confirmed by imaging or surgical reports. Physical functioning was assessed by walking capacity (6-min walk test), hand strength (Grippit), and activities of daily living (the Health Assessment Questionnaire, HAQ). Pain was assessed by pain site locations and intensity (Numeric Rating Scale, NRS). RESULTS: In total, 50 participants were included (27 males, 23 females). Median age was 41 years (range 16 to 87 years), 34 (68%) had SSS. The estimated median age at first symptom onset was 33 years (95% confidence interval (CI) 29 to 43 years), range 10 to 67 years. The majority had multiple spinal levels affected. The walking distance was 110 m shorter in the SSS group (95% CI - 172 to - 40 m) as compared with the non-SSS group (p < 0.01). There was no considerable difference in hand strength between the two groups. Mean HAQ scores (0-3) for walking and hygiene were significantly higher in the SSS group, reflecting more activity limitations. Mean differences were 0.9 (95% CI 0.3 to 1.4, p < 0.01) and 0.6 (95% CI 0.2 to 1.0, p < 0.01). Pain intensity (NRS 0-10) was also significantly higher in the SSS group with a mean difference of 3.2 (95% CI 0.6 to 5.6, p = 0.02). CONCLUSIONS: SSS was highly prevalent in Norwegian adults with achondroplasia, with symptom onset at young age, and multiple spinal levels affected. The presence of SSS was associated with reduced walking distance, activity limitations, and more pain. The findings underline the importance of thorough assessment and monitoring of SSS in achondroplasia, including a formal assessment of physical functioning.

Fatigue and pain in children and adults with multiple osteochondromas in Norway, a cross-sectional study.

BACKGROUND: Multiple Osteochondromas (MO) is a rare skeletal disorder frequently needing orthopaedic surgery. High prevalence of pain has been reported, however fatigue has not previously been investigated. PURPOSE: Our aims were to investigate prevalence of fatigue and pain in Norwegian children and adults with MO. Furthermore to compare prevalence of fatigue with reported prevalence in other groups and explore some factors that may contribute to fatigue in this population. METHODS: Questionnaire data was obtained from 11 children and 21 adults, approximately one third of the estimated MO population in Norway. Fatigue and pain was measured with validated instruments. RESULTS: Children with MO reported significantly higher fatigue than healthy children. Adults reported significantly higher fatigue than the general Norwegian population. Six of 11 children and 20 of 21 adults reported pain. Severe fatigue was more prevalent in persons with high age, high pain intensity and many pain locations; however none of these differences were significant. CONCLUSION: High prevalence of fatigue was found in Norwegian children and adults with MO. Such findings have not been previously reported. Pain was prevalent in both children and adults. This implies that fatigue and pain warrant specific attention in clinical practice and further research regarding persons with MO.

Physical functioning and activities of daily living in adults with amyoplasia, the most common form of arthrogryposis. A cross-sectional study.

BACKGROUND: Amyoplasia, the most common form of arthrogryposis is characterized by typical deformities of the joints and replacement of skeletal muscles by fibrous tissue and fat. There is sparse literature on adaptation to adult life with amyoplasia. PURPOSE: To describe physical function and activity strategies in adults with amyoplasia, as this knowledge is important for relevant function-enhancing measures. MATERIALS AND METHODS: Twenty-two adults (20-91 years) with amyoplasia participated. Demographic factors and clinical history were registered. Body proportions were measured. Joint mobility and muscle strength in the upper limbs were examined. The Functional Independent Measure was used to assess performance of activities of daily living. Compensatory strategies were described. RESULTS: The majority had undergone comprehensive conservative and surgical treatment. Mean height was below typical. Range of motion was below lower limit of normal in most joints, passive range of motion was mainly larger than active. Muscle strength was reduced for most movements. Seven were independent in all activities. Need of assistance was highest regarding bathing and dressing. A variety of compensatory strategies were used. CONCLUSIONS: Adults with amyoplasia are heterogeneous regarding function. Independence in everyday life requires a combination of muscle strength to move against gravity, ability to passive joint motion, and use of compensatory strategies. Implications for rehabilitation The ability to joint motion in the upper extremities is essential for independency in activities of daily living, especially when the muscle strength is impaired. Training of muscle strength is recommended, whenever possible, as muscle strength to move against gravity makes the performing of everyday tasks easier. The use of compensatory techniques, adaptions to the environment and relevant, often custom made, assistive devices is required to perform activities of daily living. Living an active life with physical challenges like in amyoplasia requires flexible and individually adapted solutions.

Adults Living With Amyoplasia: Function, Psychosocial Aspects, and the Benefit of AMC Support Groups.

Little is known about how adults manage living with amyoplasia. Two studies concerning adults with amyoplasia were conducted; a cross-sectional study and a qualitative study. The aims were to describe body functions, activity and participation, and to explore psychosocial dimensions. This article also emphasizes the importance of Patient Support Groups as arenas for sharing experience and gaining knowledge.

Gain-of-function mutations in the mechanically activated ion channel PIEZO2 cause a subtype of Distal Arthrogryposis.

Mechanotransduction, the pathway by which mechanical forces are translated to biological signals, plays important but poorly characterized roles in physiology. PIEZOs are recently identified, widely expressed, mechanically activated ion channels that are hypothesized to play a role in mechanotransduction in mammals. Here, we describe two distinct PIEZO2 mutations in patients with a subtype of Distal Arthrogryposis Type 5 characterized by generalized autosomal dominant contractures with limited eye movements, restrictive lung disease, and variable absence of cruciate knee ligaments. Electrophysiological studies reveal that the two PIEZO2 mutations affect biophysical properties related to channel inactivation: both E2727del and I802F mutations cause the PIEZO2-dependent, mechanically activated currents to recover faster from inactivation, while E2727del also causes a slowing of inactivation. Both types of changes in kinetics result in increased channel activity in response to a given mechanical stimulus, suggesting that Distal Arthrogryposis Type 5 can be caused by gain-of-function mutations in PIEZO2. We further show that overexpression of mutated PIEZO2 cDNAs does not cause constitutive activity or toxicity to cells, indicating that the observed phenotype is likely due to a mechanotransduction defect. Our studies identify a type of channelopathy and link the dysfunction of mechanically activated ion channels to developmental malformations and joint contractures.

Amyoplasia: a case report of an old woman.

PURPOSE: Little information exists about the long-term outcome of amyoplasia. In this article, a case report of a 93-year old woman is presented including both the development of the physical limitations and coping strategies. METHOD: The medical records, physical examinations and personal interviews during the last 10 years, autobiographical essays and personal photographs were included. RESULTS: Eleven surgical procedures were performed during childhood and ten during adulthood. Ambulation without aids was possible up to the age of 37 years. Thereafter, the muscular force declined gradually, first in the legs and later in the arms. Musculoskeletal pain decreased during ageing. There was an increasing demand to use technical aids. Seniority brought about several diseases, which complicated the quality of life. The woman stayed 32 years of her life in work. CONCLUSIONS: A high age can be achieved with amyoplasia although the disability increases due to a gradual deterioration of muscular force. The personal experiences of the woman suggest that her active and creative attitude towards her disability may have contributed to the quality of her life. This may encourage people with amyoplasia and their care givers. IMPLICATIONS FOR REHABILITATION: • There are no data about ageing and life-long prognosis of amyoplasia. • Severe physical limitations in amyoplasia are compatible with a long and meaningful life. • Muscular force decreases during adult life. Therefore, a potential risk of overtraining should be considered.