Age-appropriate body mass index in children with achondroplasia: interpretation in relation to indexes of height

Review of patients with achondroplasia: a single-center's experience with follow-up and associated morbidities

Achondroplasia (ACH; MIM #100,800), caused by a heterozygous gain of function pathogenic variant in the fibroblast growth factor receptor 3 gene (FGFR3; MIM*134,934), is the most prevalent and most readily identifiable cause of disproportionate short stature that is compatible with life. In addition, individuals with achondroplasia face significant medical, functional, and psychosocial challenges throughout their lives. This study assessed associated morbidities in patients with achondroplasia at a single center in Turkey. In this study, the clinical findings and associated morbidities of a group of patients with achondroplasia (n = 68) with clinical multidisciplinary follow-up at a single center between the years 2005-2023 are evaluated retrospectively. A total of 68 patients, 30 male (44.1%) and 38 female (55.9%), were evaluated. In the majority (84.2%) of patients, shortness of extremities was detected in the prenatal period at an average of 28.7 gestational weeks (± 3.6 SDS) with the aid of ultrasonography. More than half (n = 34/63, 54%) of the patients had a father of advanced paternal age (≥ 35 years). Among the complications, respiratory system manifestations, including obstructive sleep apnea (70%), ear-nose-throat manifestations including adenoid hypertrophy (56.6%) and otitis media (54.7%), neurological manifestations due to foramen magnum stenosis (53.2%), and skeletal manifestations including scoliosis (28.8%), are represented among the most common. The mortality rate was 7.3% (n = 5/68).Conclusion: This study not only represents the first retrospective analysis of the associated morbidities of patients with achondroplasia from a single center in Turkey but also will provide a reference point for future studies.

Vosoritide therapy in children with achondroplasia aged 3-59 months: a multinational, randomised, double-blind, placebo-controlled, phase 2 trial

BACKGROUND

Vosoritide is a recombinant C-type natriuretic peptide analogue that increases annualised growth velocity in children with achondroplasia aged 5-18 years. We aimed to assess the safety and efficacy of vosoritide in infants and children younger than 5 years.

METHODS

This double-blind, randomised, placebo-controlled, phase 2 trial was done in 16 hospitals across Australia, Japan, the UK, and the USA. Children younger than 60 months with a clinical diagnosis of achondroplasia confirmed by genetic testing and who had completed a baseline growth study or observation period were enrolled into one of three sequential cohorts based on age at screening: 24-59 months (cohort 1); 6-23 months (cohort 2); and 0-5 months (cohort 3). Each cohort included sentinels who received vosoritide to determine appropriate daily drug dose, with the remainder randomly assigned (1:1) within each age stratum (except in Japan, where participants were randomly assigned within each cohort) to receive daily subcutaneous injections of vosoritide (30·0 μg/kg for infants aged 0-23 months; 15·0 μg/kg for children aged 24-59 months) or placebo for 52 weeks. Participants, caregivers, investigators, and the sponsor were masked to treatment assignment. The first primary outcome was safety and tolerability, assessed in all participants who received at least one study dose. The second primary outcome was change in height Z score at 52 weeks from baseline, analysed in all randomly assigned participants. This trial is registered with EudraCT, 2016-003826-18, and ClinicalTrials.gov, NCT03583697.

FINDINGS

Between May 13, 2018, and March 1, 2021, 75 participants were recruited (37 [49%] females). 11 were assigned as sentinels, whereas 32 were randomly assigned to receive vosoritide and 32 placebo. Two participants discontinued treatment and the study: one in the vosoritide group (death) and one in the placebo group (withdrawal). Adverse events occurred in all 75 (100%) participants (annual rate 204·5 adverse events per patient in the vosoritide group and 73·6 per patient in the placebo group), most of which were transient injection-site reactions and injection-site erythema. Serious adverse events occurred in three (7%) participants in the vosoritide group (decreased oxygen saturation, respiratory syncytial virus bronchiolitis and sudden infant death syndrome, and pneumonia) and six (19%) participants in the placebo group (petit mal epilepsy, autism, gastroenteritis, vomiting and parainfluenza virus infection, respiratory distress, and skull fracture and otitis media). The least-squares mean difference for change from baseline in height Z score between the vosoritide and placebo groups was 0·25 (95% CI -0·02 to 0·53).

INTERPRETATION

Children with achondroplasia aged 3-59 months receiving vosoritide for 52 weeks had a mild adverse event profile and gain in the change in height Z score from baseline.

FUNDING

BioMarin Pharmaceutical.

Growth patterns of young achondroplasia patients in Korea and predictability of neurosurgical procedures

BACKGROUND

Achondroplasia is an autosomal dominant disorder mainly affecting bony growth, typically resulting in markedly short stature. From a neurosurgical viewpoint, patients sometimes develop spinal cord compression at the narrowed foramen magnum and hydrocephalus. This study aims to construct growth references for height, weight, and head circumference (HC) of young achondroplasia patients in Korea and to evaluate the predictability of the necessity and timing of neurosurgical procedures through growth patterns.

METHODS

Growth data were collected from achondroplasia patients who visited our institution between January 2002 and August 2022. First, we constructed percentile growth curves of height, weight, and HC for the patients under 3 years of age with the generalized additive model for location, scale, and shape (GAMLSS). Second, the growth patterns of the patients with hydrocephalus who underwent neurosurgical procedures such as foramen magnum decompression (FMD) and ventriculoperitoneal (VP) shunt were analyzed.

RESULTS

There were 125 achondroplasia patients, including 67 males and 58 females. Among 125 patients, 46 underwent FMD, and 5 underwent VP shunt. As short stature and macrocephaly were typical characteristics of achondroplasia, the height of achondroplasia was lower than that of the general population, and HC in achondroplasia showed accelerated growth postnatally. There were no significant changes in HC in hydrocephalus patients before they underwent neurosurgical procedures. The influence of hydrocephalus on the growth patterns of HC in achondroplasia seemed insignificant.

CONCLUSION

Growth references for height, weight, and HC in young achondroplasia patients were constructed. It is the first report of growth patterns of achondroplasia in Korea. Unlike other pediatric patients, the diagnosis of hydrocephalus and the necessity of neurosurgical procedures are hard to be predicted with HC in achondroplasia. Neuroimaging should be considered for achondroplasia patients with neurological symptoms.

A scoping review of nutrition issues and management strategies in individuals with skeletal dysplasia

PURPOSE

Skeletal dysplasia are heterogeneous conditions affecting the skeleton. Common nutrition issues include feeding difficulties, obesity, and metabolic complications. This systematic scoping review aimed to identify key nutrition issues, management strategies, and gaps in knowledge regarding nutrition in skeletal dysplasia.

METHODS

The databases Ovid MEDLINE, Ovid EMBASE, Ebsco CINAHL, Scopus, and Cochrane Central Register of Controlled Trials and Database of Systematic Reviews were searched. Reference lists and citing literature for included studies were searched. Eligible studies included participants with skeletal dysplasia and described: anthropometry, body composition, nutrition-related biochemistry, clinical issues, dietary intake, measured energy or nutrition requirements, or nutrition interventions.

RESULTS

The literature search identified 8509 references from which 138 studies were included (130 observational, 3 intervention, 2 systematic reviews, and 3 clinical guidelines). Across 17 diagnoses identified, most studies described osteogenesis imperfecta (n = 50) and achondroplasia or hypochondroplasia (n = 47). Nutrition-related clinical issues, biochemistry, obesity, and metabolic complications were most commonly reported, and few studies measured energy requirements (n = 5).

CONCLUSION

Nutrition-related comorbidities are documented in skeletal dysplasia; yet, evidence to guide management is scarce. Evidence describing nutrition in rarer skeletal dysplasia conditions is lacking. Advances in skeletal dysplasia nutrition knowledge is needed to optimize broader health outcomes.

Craniofacial Features of Dwarfism in the Paintings of Velázquez

This study describes the craniofacial features of achondroplastic dwarfism in the paintings of Velázquez. In a PubMed search, using [Velázquez] and [dwarf], 13 titles were found. In a Google Image search, [Velázquez] and [dwarf] retrieved 5 paintings. The craniofacial manifestations of the dwarfs depicted in the paintings were analyzed. Frontal bossing, antimongoloid slant, depressed nasal bridge (saddle nose), bulbous tip, malar hypoplasia, malocclusion, and chin asymmetry were observed. The presence of each manifestation was checked. In 5 paintings, portraits of 6 dwarfs having craniofacial deformities were found: Mariabárbola Asquin (left) in Las Meninas , Nicolasito Pertusato (right) in Las Meninas , Portrait of Sebastián de Morra, Portrait of Francisco Lezcano, The Jester Don Diego de Acedo, and Prince Balthasar Charles with a Dwarf. The most frequent craniofacial manifestation was malar hypoplasia (100%), followed by a bulbous tip (83.3%), saddle nose (66.7%), and frontal bossing (50%). Antimongoloid slant, malocclusion, and chin asymmetry were relatively rare (16.7% each). Through an analysis of 6 dwarfs in Velázquez's paintings, we can show that he realized and frequently expressed the craniofacial manifestations of achondroplasia: malar hypoplasia, bulbous tip, saddle nose, and frontal bossing. Despite the rarity of these presentations, he was also aware of antimongoloid slant, malocclusion, and chin asymmetry. Velázquez was a famous painter in the 17th century (i.e., during the Baroque period). Based on his excellent expression of the craniofacial manifestations of dwarfism, we can assume that he had a sound knowledge of anatomy, as well as malformations.

Craniofacial and Dental Manifestations in Pediatric Patients with Achondroplasia: A Case Report and Clinical View

Aim

The aim of this case report is to describe the dentofacial manifestations of achondroplasia and highlight concerns associated with dental management of pediatric patients with achondroplasia.

Background

Achondroplasia is the most common form of skeletal dysplasia (dwarfism) with clinical manifestations including disproportionate limb shortening and stunted stature. The craniofacial characteristics of achondroplasia are relative macrocephaly, depression of the nasal bridge, and maxillary hypoplasia. Special precautions are necessary during dental management of pediatric patients with achondroplasia due to a large head size, implanted shunts, airway obstruction, and difficulty in head control.

Case description

A 6 years and 7 months male, the patient was diagnosed with achondroplasia, currently receiving vitamin D, no known drug allergy, and a mixed dentition stage with multiple caries, mouth breather, and a high risk of further caries based on a caries risk assessment due to poor oral hygiene. As the patient was uncooperative and required extensive dental care, dental rehabilitation was conducted under general anesthesia using oral intubation due to nasal obstruction. Future examinations were planned for every 3 months.

Conclusion

The current case demonstrated that the characteristics of achondroplasia might cause respiratory, neurological, skeletal, orthodontic, and psychological difficulties. Pediatric dentists who treat these patients must be able to detect these characteristics and difficulties, as dental treatment is limited by practical issues associated with this condition.

Clinical significance

The characteristic features of achondroplasia are attributed to skeletal, respiratory, neurologic, orthodontic, and psychosocial issues. The dentist should be aware of the features of achondroplasia, which can potentially restrict dental management.

How to cite this article

Almutiry A, Alotaibi F, Almutiry B, et al. Craniofacial and Dental Manifestations in Pediatric Patients with Achondroplasia: A Case Report and Clinical View. Int J Clin Pediatr Dent 2023;16(2):409-415.

What to Expect of Feeding Abilities and Nutritional Aspects in Achondroplasia Patients: A Narrative Review

Achondroplasia is an autosomal dominant genetic disease representing the most common form of human skeletal dysplasia: almost all individuals with achondroplasia have identifiable mutations in the fibroblast growth factor receptor type 3 (FGFR3) gene. The cardinal features of this condition and its inheritance have been well-established, but the occurrence of feeding and nutritional complications has received little prominence. In infancy, the presence of floppiness and neurological injury due to foramen magnum stenosis may impair the feeding function of a newborn with achondroplasia. Along with growth, the optimal development of feeding skills may be affected by variable interactions between midface hypoplasia, sleep apnea disturbance, and structural anomalies. Anterior open bite, prognathic mandible, retrognathic maxilla, and relative macroglossia may adversely impact masticatory and respiratory functions. Independence during mealtimes in achondroplasia is usually achieved later than peers. Early supervision of nutritional intake should proceed into adolescence and adulthood because of the increased risk of obesity and respiratory problems and their resulting sequelae. Due to the multisystem involvement, oral motor dysfunction, nutrition, and gastrointestinal issues require special attention and personalized management to facilitate optimal outcomes, especially because of the novel therapeutic options in achondroplasia, which could alter the progression of this rare disease.

Achondroplasia: Update on diagnosis, follow-up and treatment

Achondroplasia requieres multidisciplinary follow-up, with the aim of preventing and managing complications, improving the quality of life of people who suffer from it and favoring their independence and social inclusion. This review is justified by the multiple publications generated in recent years that have carried out a change in its management. Different guidelines and recommendations have been developed, among which the one made by the American Academy of Pediatrics in 2005 recently updated (2020), the Japanese guide (2020), the first European Consensus (2021) and the International Consensus on the diagnosis, approach multidisciplinary approach and management of individuals with achondroplasia throughout life (2021). However, and despite these recommendations, there is currently a great worldwide variability in the management of people with achondroplasia, with medical, functional and psychosocial consequences in patients and their families. Therefore, it is essential to integrate these recommendations into daily clinical practice, taking into account the particular situation of each health system.

[Clinical features and FGFR3 mutations of children with achondroplasia]

OBJECTIVES

To study the clinical features and fibroblast growth factor receptor 3 (FGFR3) gene mutations of children with achondroplasia (ACH) through an analysis of 17 cases.

METHODS

A retrospective analysis was performed on the clinical data and FGFR3 gene detection results of 17 children with ACH who were diagnosed from January 2009 to October 2021.

RESULTS

Of the 17 children with ACH, common clinical manifestations included disproportionate short stature (100%, 17/17), macrocephaly (100%, 17/17), trident hand (82%, 14/17), and genu varum (88%, 15/17). The common imaging findings were rhizomelic shortening of the long bones (100%, 17/17) and narrowing of the lumbar intervertebral space (88%, 15/17). Major complications included skeletal dysplasia (100%, 17/17), middle ear dysfunction (82%, 14/17), motor/language developmental delay (88%, 15/17), chronic pain (59%, 10/17), sleep apnea (53%, 9/17), obesity (41%, 7/17), foramen magnum stenosis (35%, 6/17), and hydrocephalus (24%, 4/17). All 17 children (100%) had FGFR3 mutations, among whom 13 had c.1138G>A hotspot mutations of the FGFR3 gene, 2 had c.1138G>C mutations of the FGFR3 gene, and 2 had unreported mutations, with c.1252C>T mutations of the FGFR3 gene in one child and c.445+2_445+5delTAGG mutations of the FGFR3 gene in the other child.

CONCLUSIONS

This study identifies the unreported mutation sites of the FGFR3 gene, which extends the gene mutation spectrum of ACH. ACH is a progressive disease requiring lifelong management through multidisciplinary collaboration.

Infigratinib in children with achondroplasia: the PROPEL and PROPEL 2 studies

Background:

Achondroplasia is the most common short-limbed skeletal dysplasia resulting from gain-of-function pathogenic variants in fibroblast growth factor receptor 3 ( FGFR3) gene, a negative regulator of endochondral bone formation. Most treatment options are symptomatic, targeting medical complications. Infigratinib is an orally bioavailable, FGFR1–3 selective tyrosine kinase inhibitor being investigated as a direct therapeutic strategy to counteract FGFR3 overactivity in achondroplasia.

Objectives:

The main objective of PROPEL is to collect baseline data of children with achondroplasia being considered for future enrollment in interventional studies sponsored by QED Therapeutics. The objectives of PROPEL 2 are to obtain preliminary evidence of safety and efficacy of oral infigratinib in children with achondroplasia, to identify the infigratinib dose to be explored in future studies, and to characterize the pharmacokinetic (PK) profile of infigratinib and major metabolites.

Design:

PROPEL (NCT04035811) is a prospective, noninterventional clinical study designed to characterize the natural history and collect baseline data of children with achondroplasia over 6−24 months. PROPEL 2 (NCT04265651), a prospective, phase II, open-label study of infigratinib in children with achondroplasia, consists of a dose-escalation, dose-finding, and dose-expansion phase to confirm the selected dose, and a PK substudy.

Methods and analysis:

Children aged 3−11 years with achondroplasia who completed ⩾6 months in PROPEL are eligible for PROPEL 2. Primary endpoints include treatment-emergent adverse events and change from baseline in annualized height velocity. Four cohorts at ascending dose levels are planned for dose escalation. The selected dose will be confirmed in the dose-expansion phase.

Ethics:

PROPEL and PROPEL 2 are being conducted in accordance with the International Conference on Harmonization Good Clinical Practice guidelines, principles of the Declaration of Helsinki, and relevant human clinical research and data privacy regulations. Protocols have been approved by local health authorities, ethics committees, and institutions as applicable. Parents/legally authorized representatives are required to provide signed informed consent; signed informed assent by the child is also required, where applicable.

Discussion:

PROPEL and PROPEL 2 will provide preliminary evidence of the safety and efficacy of infigratinib as precision treatment of children with achondroplasia and will inform the design of future studies of FGFR-targeted agents in achondroplasia.

Registration:

ClinicalTrials.gov: NCT04035811; NCT04265651.

International Consensus Statement on the diagnosis, multidisciplinary management and lifelong care of individuals with achondroplasia

Achondroplasia, the most common skeletal dysplasia, is characterized by a variety of medical, functional and psychosocial challenges across the lifespan. The condition is caused by a common, recurring, gain-of-function mutation in FGFR3, the gene that encodes fibroblast growth factor receptor 3. This mutation leads to impaired endochondral ossification of the human skeleton. The clinical and radiographic hallmarks of achondroplasia make accurate diagnosis possible in most patients. However, marked variability exists in the clinical care pathways and protocols practised by clinicians who manage children and adults with this condition. A group of 55 international experts from 16 countries and 5 continents have developed consensus statements and recommendations that aim to capture the key challenges and optimal management of achondroplasia across each major life stage and sub-specialty area, using a modified Delphi process. The primary purpose of this first International Consensus Statement is to facilitate the improvement and standardization of care for children and adults with achondroplasia worldwide in order to optimize their clinical outcomes and quality of life.

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

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-02141-4.

Pharmacokinetics and Exposure-Response of Vosoritide in Children with Achondroplasia

BACKGROUND AND OBJECTIVE

Vosoritide, an analog of C-type natriuretic peptide, has been developed for the treatment of children with achondroplasia. The pharmacokinetics of vosoritide and relationships between plasma exposure and efficacy, biomarkers, and safety endpoints were evaluated in a phase II, open-label, dose-escalation study (N = 35 patients aged 5-14 years who received daily subcutaneous injections for 24 months) and a phase III, double-blind, placebo-controlled study (N = 60 patients aged 5-18 years randomized to receive daily subcutaneous injections for 52 weeks).

METHODS

Pharmacokinetic parameters for both studies were obtained from non-compartmental analysis. Potential correlations between vosoritide exposure and changes in annualized growth velocity, collagen type X marker (CXM; a biomarker of endochondral ossification), cyclic guanosine monophosphate (cGMP; a biomarker of pharmacological activity), heart rate, and systolic and diastolic blood pressures were then evaluated.

RESULTS

The exposure-response relationships for changes in both annualized growth velocity and the CXM biomarker saturated at 15 μg/kg, while systemic pharmacological activity, as measured by urinary cGMP, was near maximal or saturated at exposures obtained at the highest dose studied (i.e. 30 μg/kg). This suggested that the additional bioactivity was likely in tissues not related to endochondral bone formation. In the phase III study, following subcutaneous administration at the recommended dose of 15 μg/kg to patients with achondroplasia aged 5-18 years, vosoritide was rapidly absorbed with a median time to maximal plasma concentration (C_max) of 15 minutes, and cleared with a mean half-life of 27.9 minutes after 52 weeks of treatment. Vosoritide exposure (C_max and area under the concentration-time curve [AUC]) was consistent across visits. No evidence of accumulation with once-daily dosing was observed. Total anti-vosoritide antibody (TAb) responses were detected in the serum of 25 of 60 (42%) treated patients in the phase III study, with no apparent impact of TAb development noted on annualized growth velocity or vosoritide exposure. Across the exposure range obtained with 15 µg/kg in the phase III study, no meaningful correlations between vosoritide plasma exposure and changes in annualized growth velocity or CXM, or changes from predose heart rate, and systolic or diastolic blood pressures were observed.

CONCLUSIONS

The results support the recommended dose of vosoritide 15 µg/kg for once-daily subcutaneous administration in patients with achondroplasia aged ≥ 5 years whose epiphyses are not closed.

CLINICAL TRIALS REGISTRATION

NCT02055157, NCT03197766, and NCT01603095.

Lifetime impact of achondroplasia: Current evidence and perspectives on the natural history

Achondroplasia, the most common form of disproportionate short stature, is caused by a variant in the fibroblast growth factor receptor 3 (FGFR3) gene. Advances in drug treatment for achondroplasia have underscored the need to better understand the natural history of this condition. This article provides a critical review and discussion of the natural history of achondroplasia based on current literature evidence and the perspectives of clinicians with extensive knowledge and practical experience in managing individuals with this diagnosis. This review draws evidence from recent and ongoing longitudinal natural history studies, supplemented with relevant cross-sectional studies where longitudinal research is lacking, to summarize the current knowledge on the nature, incidence, chronology, and interrelationships of achondroplasia-related comorbidities across the lifespan. When possible, data related to adults are presented separately from data specific to children and adolescents. Gaps in knowledge regarding clinical care are identified and areas for future research are recommended and discussed.

Growth in achondroplasia, from birth to adulthood, analysed by the JPA-2 model

OBJECTIVES

In general population, there are three phases in the human growth curve: infancy, childhood and puberty, with different main factors involved in their regulation and mathematical models to fit them. Achondroplasia children experience a fast decreasing growth during infancy and an "adolescent growth spurt"; however, there are no longitudinal studies that cover the analysis of the whole post-natal growth. Here we analyse the whole growth curve from infancy to adulthood applying the JPA-2 mathematical model.

METHODS

Twenty-seven patients, 17 girls and 10 boys with achondroplasia, who reached adult size, were included. Height growth data was collected from birth until adulthood. Individual growth curves were estimated by fitting the JPA-2 model to each individual's height for age data.

RESULTS

Height growth velocity curves show that after a period of fast decreasing growth velocity since birth, with a mean of 9.7 cm/year at 1 year old, the growth velocity is stable in late preschool years, with a mean of 4.2 cm/year. In boys, age and peak height velocity in puberty were 13.75 years and 5.08 cm/year and reach a mean adult height of 130.52 cm. In girls, the age and peak height velocity in puberty were 11.1 years and 4.32 cm/year and reach a mean adult height of 119.2 cm.

CONCLUSIONS

The study of individual growth curves in achondroplasia children by the JPA-2 model shows the three periods, infancy, childhood and puberty, with a similar shape but lesser in magnitude than general population.

Clinical charts for surveillance of growth and body proportion development in achondroplasia and examples of their use

Clinical surveillance of infants and children with achondroplasia necessitates syndrome-specific charts due to extreme short stature with deviating body proportions. Height, arm span and leg length develop far below normal population ranges. We present growth and body proportion charts for ages 0-20 years, constructed from semi-longitudinal standardized measurements of about 450 children, along with some examples of achondroplasia typical and atypical growth pattern. We combine head circumference, height and weight for 0-4 years into one (infancy) page and height and weight for 4-20 years in another (childhood-adolescence) using nonlinear axes to account for the rapidly decreasing growth velocity. Similarly, weight and BMI are based on nonlinear axes to balance wide SD-channels at higher and narrow SD-channels at lower levels of weight/BMI. Charts for following sitting height, sitting height/height ratio, arm span, leg and foot length are also presented. Clinical examples illustrating the applicability of the charts include cases of extreme prematurity, extreme head circumference development before and after shunting, achondroplasia complicated by chromosomal or additional genetic abnormality and by growth hormone deficiency as well as of evaluating growth promoting therapy.

Health Supervision for People With Achondroplasia

Achondroplasia is the most common short-stature skeletal dysplasia, additionally marked by rhizomelia, macrocephaly, midface hypoplasia, and normal cognition. Potential medical complications associated with achondroplasia include lower extremity long bone bowing, middle-ear dysfunction, obstructive sleep apnea, and, more rarely, cervicomedullary compression, hydrocephalus, thoracolumbar kyphosis, and central sleep apnea. This is the second revision to the original 1995 health supervision guidance from the American Academy of Pediatrics for caring for patients with achondroplasia. Although many of the previously published recommendations remain appropriate for contemporary medical care, this document highlights interval advancements in the clinical methods available to monitor for complications associated with achondroplasia. This document is intended to provide guidance for health care providers to help identify individual patients at high risk of developing serious sequelae and to enable intervention before complications develop.

Clinical Practice Guidelines for Achondroplasia

Achondroplasia (ACH) is a skeletal dysplasia that presents with limb shortening, short stature, and characteristic facial configuration. ACH is caused by mutations of the FGFR3 gene, leading to constantly activated FGFR3 and activation of its downstream intracellular signaling pathway. This results in the suppression of chondrocyte differentiation and proliferation, which in turn impairs endochondral ossification and causes short-limb short stature. ACH also causes characteristic clinical symptoms, including foramen magnum narrowing, ventricular enlargement, sleep apnea, upper airway stenosis, otitis media, a narrow thorax, spinal canal stenosis, spinal kyphosis, and deformities of the lower extremities. Although outside Japan, papers on health supervision are available, they are based on reports and questionnaire survey results. Considering the scarcity of high levels of evidence and clinical guidelines for patients with ACH, clinical practical guidelines have been developed to assist both healthcare professionals and patients in making appropriate decisions in specific clinical situations. Eleven clinical questions were established and a systematic literature search was conducted using PubMed/MEDLINE. Evidence-based recommendations were developed, and the guidelines describe the recommendations related to the clinical management of ACH. We anticipate that these clinical practice guidelines for ACH will be useful for healthcare professionals and patients alike.

The importance of anthropological methods in the diagnosis of rare diseases

Most of inborn errors of metabolism (IEMs) and rare endocrine-metabolic diseases (REMD) are rare diseases. According to the European Commission on Public Health, a rare disease is defined, based on its prevalence, as one affecting one in 2000 people. Many IEMs affect body stature, cause craniofacial abnormalities, and disturb the developmental process. Therefore, body proportion, dysmorphic characteristics, and morphological parameters must be assessed and closely monitored. This can be achieved only with the help of an anthropologist who has adequate tools. This is why the role of an anthropologist in collaboration with the physician in the diagnostic process is not to be underestimated. Clinical anthropologists contribute to assessing physical development and improve our understanding of the natural history of rare metabolic diseases. This paper presents anthropometric techniques and methods, such as analysis of demographic data, anthropometric parameters at birth, percentile charts, growth patterns, bioimpedance, somatometric profiles, craniofacial profiles, body proportion indices, and mathematical models of growth curves used in certain rare diseases. Contemporary anthropological methods play an important role in the diagnostic process of rare genetic diseases.

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.

Achondroplasia: a comprehensive clinical review

Achondroplasia is the most common of the skeletal dysplasias that result in marked short stature (dwarfism). Although its clinical and radiologic phenotype has been described for more than 50 years, there is still a great deal to be learned about the medical issues that arise secondary to this diagnosis, the manner in which these are best diagnosed and addressed, and whether preventive strategies can ameliorate the problems that can compromise the health and well being of affected individuals. This review provides both an updated discussion of the care needs of those with achondroplasia and an exploration of the limits of evidence that is available regarding care recommendations, controversies that are currently present, and the many areas of ignorance that remain.

Acanthosis nigricans in achondroplasia

Acanthosis nigricans (AN) in those with achondroplasia has been reported occasionally in the literature previously. Other disorders arising from constitutive activation of FGFR3 also manifest AN at various frequencies. We assessed the prevalence of AN in a sequential series of 477 individuals with achondroplasia. Using a REDCap database, we collected and analyzed what other features or medical issues may co-occur with AN in those with achondroplasia. AN arises in approximately 10% of individuals with achondroplasia. It usually first appears in preadolescence or adolescence, is more likely in the non-White population and in those who are obese. It is not severe and generally will need no treatment. It is not associated with any evident risk for neither hyperinsulinemic states nor malignancy, and therefore, no special investigations are warranted when it is recognized. Thus, clinicians should not be surprised or concerned upon discovering this finding in those with achondroplasia. In addition, the mechanisms and genetic causes of AN are detailed.

Growth in achondroplasia: Development of height, weight, head circumference, and body mass index in a European cohort

As growth references for achondroplasia are limited to reports from United States, Japan, Argentina, and Australia, the aim of this study was to construct growth references for height, weight, head circumference, and body mass index (BMI) from a European cohort of children with achondroplasia and to discuss the development of these anthropometric variables. A mix of cross-sectional and longitudinal, retrospective, and prospective data from 466 children with achondroplasia and 4,375 measuring occasions were modeled with generalized additive model for location, scale and shape (GAMLSS) to sex-specific references for ages 0 to 20 years. Loss in height position, that is, reduction in height standard deviation scores, occurred mainly during first 2 years of life while pubertal growth seemed normal if related to adult height. Adult height was 132 cm in boys and 124 cm in girls with a variability comparable to that of the general population and seems to be remarkably similar in most studies of children with achondroplasia. BMI had a syndrome-specific development that was not comparable to BMI development in the general population. Weight and BMI might be misleading when evaluating, for example, metabolic health in achondroplasia. Head circumference reached adult head size earlier than in the general population. Increased tempo of head circumference growth necessitates thus close clinical follow-up during first postnatal years.

Early postnatal soluble FGFR3 therapy prevents the atypical development of obesity in achondroplasia

Background

Achondroplasia is a rare genetic disease is characterized by abnormal bone development and early obesity. While the bone aspect of the disease has been thoroughly studied, early obesity affecting approximately 50% of them during childhood has been somewhat neglected. It nevertheless represents a major health problem in these patients, and is associated to life-threatening complications including increasing risk of cardiovascular pathologies. We have thus decided to study obesity in patients and to use the mouse model to evaluate if soluble FGFR3 therapy, an innovative treatment approach for achondroplasia, could also impact the development of this significant complication.

Methods and findings

To achieve this, we have first fully characterized the metabolic deregulations in these patients by conducting a longitudinal retrospective study, in children with achondroplasia Anthropometric, densitometric measures as well as several blood parameters were recorded and compared between three age groups ranging from [0–3], [4–8] and [9–18] years old. Our results show unexpected results with the development of an atypical obesity with preferential fat deposition in the abdomen that is remarkably not associated with classical complications of obesity such as diabetes or hypercholosterolemia. Because it is not associated with diabetes, the atypical obesity has not been studied in the past even though it is recognized as a real problem in these patients. These results were validated in a murine model of achondroplasia (Fgfr3^ach/+) where similar visceral adiposity was observed. Unexpected alterations in glucose metabolism were highlighted during high-fat diet. Glucose, insulin or lipid levels remained low, without the development of diabetes. Very interestingly, in achondroplasia mice treated with soluble FGFR3 during the growth period (from D3 to D22), the development of these metabolic deregulations was prevented in adult animals (between 4 and 14 weeks of age). The lean-over-fat tissues ratio was restored and glucose metabolism showed normal levels. Treating Fgfr3^ach/+ mice with soluble FGFR3 during the growth period, prevented the development of these metabolic deregulations in adult animals and restored lean-over-fat tissues ratio as well as glucose metabolism in adult animals.

Conclusion

This study demonstrate that achondroplasia patients develop an atypical obesity with preferential abdominal obesity not associated with classical complications. These results suggest that achondroplasia induces an uncommon metabolism of energy, directly linked to the FGFR3 mutation. These data strongly suggest that this common complication of achondroplasia should be included in the clinical management of patients. In this context, sFGFR3 proved to be a promising treatment for achondroplasia by normalizing the biology at different levels, not only restoring bone growth but also preventing the atypical visceral obesity and some metabolic deregulations.

Leg length, sitting height, and body proportions references for achondroplasia: New tools for monitoring growth

Achondroplasia is the most common form of inherited disproportionate short stature. We report leg length, sitting height, and body proportion curves for achondroplasia. Seven centile format of sitting height, leg length, sitting height/leg length ratio, sitting height/height ratio, and head circumference/height ratio were estimated by the LMS method. The Q-test was applied to assess the goodness of fit. For comparison, centiles of sitting height and leg length were graphed using Argentine national growth references for achondroplasia and non-achondroplasia populations. The sample consisted of 342 children with achondroplasia (171 males, 171 females) aged 0-18 years. The median (interquartile range) number of measurements per child was 6 (3, 12) for sitting height and 8 (3, 13) for head circumference. Median leg length increased from 14 cm at age 1 week to 44 and 40 cm (males and females, respectively) in achondroplasia adolescents which is 3.5 cm shorter than non-achondroplasia children at age 1 week and, 38 cm shorter at adolescence. Median sitting height increased from 34 cm at birth to 86 and 81 in adolescents' boys and girls respectively, only 5 cm shorter than non-achondroplasia children. Sitting height/leg length decreased from 2.61 at birth to approximately 1.90 at adolescent. Median head circumference/height ratio decreased from 0.79 at birth to 0.46 at 18 years in both sexes. Growth of lower limbs is affected early in life and becomes more noticeable throughout childhood. The disharmonic growth between the less affected trunk and the severely affected limbs determine body disproportion in achondroplasia.

Long-term follow-up of a child with Klinefelter syndrome and achondroplasia from infancy to 16 years

BACKGROUND

Achondroplasia (ACH), an autosomal dominant skeletal dysplasia, occurs in approximately 1:20,000 births. On the other hand, 47,XXY aneuploidy (Klinefelter syndrome [KS]) is the most common sex chromosome disorder, with a prevalence of approximately 1:600 males. To the best of our knowledge, only five cases of patients presenting both ACH and KS have been reported to date in the international literature. However, none of these cases has been longitudinally followed during the entire childhood.

CASE PRESENTATION

We report a male patient with ACH and KS, diagnosed in early infancy because of his typical phenotype of ACH. The diagnosis was confirmed by molecular analysis revealing a de novo heterozygous 1138 G-to-A mutation of the FGFR3 gene. During his first assessment, a karyotype was performed, which also revealed coexistence of KS. He was followed by our pediatric endocrinology team until the age of 16 years, then he was gradually transferred to adult endocrine care.

CONCLUSIONS

This is the first reported case with both conditions that was diagnosed in infancy and was longitudinally followed by a pediatric endocrinology team regularly, from infancy to late adolescence. With a typical phenotype of ACH, it is striking and noteworthy that he did not develop the classical endocrine complications of a child with KS, neither did he necessitate testosterone supplementation during his pubertal development, due to his normal virilization and testosterone levels.

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.

A height-for-age growth reference for children with achondroplasia: Expanded applications and comparison with original reference data

The height-for-age (HA) reference currently used for children with achondroplasia is not adaptable for electronic records or calculation of HA Z-scores. We report new HA curves and tables of mean and standard deviation (SD) HA, for calculating Z-scores, from birth-16 years in achondroplasia. Mixed longitudinal data were abstracted from medical records of achondroplasia patients from a single clinical practice (CIS, 1967-2004). Gender-specific height percentiles (5, 25, 50, 75, 95th) were estimated across the age continuum, using a 2 month window per time point smoothed by a quadratic smoothing algorithm. HA curves were constructed for 0-36 months and 2-16 years to optimize resolution for younger children. Mean monthly height (SD) was tabulated. These novel HA curves were compared to reference data currently in use for children with achondroplasia. 293 subjects (162 male/131 female) contributed 1,005 and 932 height measures, with greater data paucity with age. Mean HA tracked with original achondroplasia norms, particularly through mid-childhood (2-9 years), but with no evidence of a pubertal growth spurt. Standard deviation of height at each month interval increased from birth through 16 years. Birth length was lower in achondroplasia than average stature and, as expected, height deficits increased with age. A new HA reference is available for longitudinal growth assessment in achondroplasia, taking advantage of statistical modeling techniques and allowing for Z-score calculations. This is an important contribution to clinical care and research endeavors for the achondroplasia population.

Low bone mineral density in achondroplasia and hypochondroplasia

BACKGROUND

Achondroplasia (ACH) and hypochondroplasia (HCH) are the most common form of short-limb skeletal dysplasias caused by activated fibroblast growth factor receptor 3 (FGFR3) signaling. Although decreased bone mass was reported in gain-of-function mutation in Fgfr3 mice, both disorders have never been described as osteoporotic. In the present study, we evaluated bone mineral density (BMD) in ACH and HCH patients.

METHODS

We measured spinal BMD (L1-L4) in 18 ACH and four HCH patients with an average age of 19.8 ± 7.5 years (range, 10-33 years). BMD Z-score in each individual was calculated for normalizing age and gender. Correlation between body mass index (BMI) and BMD was analyzed. Moreover, BMD and Z-score were compared between ACH patients and HCH patients.

RESULTS

The average BMD of ACH/HCH patients was 0.805 ± 0.141 g/cm(2) (range, 0.554-1.056 g/cm(2) ), resulting in an average Z-score of -1.1 ± 0.8 (range, -2.4 to 0.6) of the standard value. A slightly positive correlation was observed between BMI and BMD (r = 0.45; P = 0.13). There was no significant difference in BMD and Z-score between ACH and HCH patients.

CONCLUSION

Spinal BMD was reduced in ACH/HCH patients, and was mildly correlated with individual BMI. We should carefully monitor BMD and examine osteoporosis-related symptoms in adolescent and adult ACH/HCH patients. © 2016 Japan Pediatric Society.

Limb lengthening in achondroplasia

BACKGROUND

Stature lengthening in skeletal dysplasia is a contentious issue. Specific guidelines regarding the age and sequence of surgery, methods and extent of lengthening at each stage are not uniform around the world. Despite the need for multiple surgeries, with their attendant complications, parents demanding stature lengthening are not rare, due to the social bias and psychological effects experienced by these patients. This study describes the outcome and complications of extensive stature lengthening performed at our center.

MATERIALS AND METHODS

Eight achondroplasic and one hypochondroplasic patient underwent bilateral transverse lengthening for tibiae, humeri and femora. Tibia lengthening was carried out using a ring fixator and bifocal corticotomy, while a monolateral pediatric limb reconstruction system with unifocal corticotomy was used for the femur and humerus. Lengthening of each bone segment, height gain, healing index and complications were assessed. Subgroup analysis was carried out to assess the effect of age and bone segment on the healing index.

RESULTS

Nine patients aged five to 25 years (mean age 10.2 years) underwent limb lengthening procedures for 18 tibiae, 10 femora and 8 humeri. Four patients underwent bilateral lengthening of all three segments. The mean length gain for the tibia, femur and humerus was 15.4 cm (100.7%), 9.9 cm (52.8%) and 9.6 cm (77.9%), respectively. Healing index was 25.7, 25.6 and 20.6 days/cm, respectively, for the tibia, femur and humerus. An average of 33.3% height gain was attained. Lengthening of both tibia and femur added to projected height achieved as the 3(rd) percentile of standard height in three out of four patients. In all, 33 complications were encountered (0.9 complications per segment). Healing index was not affected by age or bone segment.

CONCLUSION

Extensive limb lengthening (more than 50% over initial length) carries significant risk and should be undertaken only after due consideration.

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.

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.

Growth references for height, weight, and head circumference for Argentine children with achondroplasia

In order to prepare growth references for height, weight, and head circumference for Argentine children with Achondroplasia, 228 children (114 boys) aged 0-18 years attending the Growth Clinic at Hospital Garrahan were measured between 1992 and 2009. Centiles were calculated by LMS, a method for summarizing growth data which adjusts for skewness. Curves for centiles are obtained using the formula: [Formula: see text], where Z (α) is the normal equivalent deviate for tail area α; C100α is the weight or height centile corresponding to Z (α), t is age in years, and L(t) is (skewness)(t), M(t) is median, S (t) is coefficient variation and C(100α) (t) indicates the corresponding values of each curve at age t. Boys and girls centiles for height were similar to USA references in infancy and childhood but lower than that references at adolescence. Final height was 1.7 and 5.1 cm below USA achondroplasia references in girls and boys, respectively. Head circumference centiles were, at all ages, lower than USA references in both genders. Countries need national references for clinical growth assessment of their local population. Likewise, specific local growth references for children with some genetic conditions (such us achondroplasia) are valuable tools for detecting additional conditions affecting growth, for estimating final height and for evaluating the impact of growth-promoting treatments.

CONCLUSION

references presented here can also be used in other countries with similar ethnographics characteristics.

The skeletal dysplasias

The skeletal dysplasias (osteochondrodysplasias) are a heterogeneous group of more than 350 disorders frequently associated with orthopedic complications and varying degrees of dwarfism or short stature. These disorders are diagnosed based on radiographic, clinical, and molecular criteria. The molecular mechanisms have been elucidated in many of these disorders providing for improved clinical diagnosis and reproductive choices for affected individuals and their families. An increasing variety of medical and surgical treatment options can be offered to affected individuals to try to improve their quality of life and lifespan.

Achondroplasia: Craniofacial manifestations and considerations in dental management

Achondroplasia is the most common form of skeletal dysplasia dwarfism that manifests with stunted stature and disproportionate limb shortening. Achondroplasia is of dental interest because of its characteristic craniofacial features which include relative macrocephaly, depressed nasal bridge and maxillary hypoplasia. Presence of large head, implanted shunt, airway obstruction and difficulty in head control require special precautions during dental management. Craniofacial manifestations and considerations in dental management are presented in 11-year-old female patient with achondroplasia.

Enzyme replacement therapy for mucopolysaccharidosis VI: Growth and pubertal development in patients treated with recombinant human N-acetylgalactosamine 4-sulfatase

BACKGROUND AND METHODS: Growth failure is characteristic of untreated mucopolysaccharidosis type VI (MPS VI: Maroteaux-Lamy syndrome). Growth was studied in fifty-six MPS VI patients (5 to 29 years old) prior to and for up to 240 weeks of weekly infusions of recombinant human arylsulfatase B (rhASB) at 1 mg/kg during Phase 1/2, Phase 2, Phase 3 or Phase 3 Extension clinical trials. Height, weight, and Tanner stage data were collected. Pooled data were analyzed to determine mean height increase by treatment week, growth impacts of pubertal status, baseline urinary GAG, and age at treatment initiation. Growth rate for approximately 2 years prior to and following treatment initiation was analyzed using longitudinal modeling. RESULTS: Mean height increased by 2.9 cm after 48 weeks and 4.3 cm after 96 weeks on enzyme replacement therapy (ERT). Growth on ERT was not correlated with baseline urinary GAG. Patients under 16 years of age showed greatest increases in height on treatment. Model results based on pooled data showed significant improvement in growth rate during 96 weeks of ERT when compared to the equivalent pretreatment time period. Delayed pubertal onset or progression was noted in 10 patients entering the clinical trials; all of whom showed progression of at least one Tanner stage during 2 years on ERT, and 6 of whom (60%) completed puberty. CONCLUSION: Analysis of mean height by treatment week and longitudinal modeling demonstrate significant increase in height and growth rate in MPS VI patients receiving long-term ERT. This impact was greatest in patients aged below 16 years. Height increase may result from bone growth and/or reduction in joint contractures. Bone growth and resolution of delayed puberty may be related to improvements in general health, bone cell health, nutrition, endocrine gland function and reduced inflammation.