Research platform for children with arthrogryposis multiplex congenita: Findings from the pilot registry

Prenatal diagnosis (or lack thereof) of arthrogryposis multiplex congenita and its impact on the perinatal experience of parents: A retrospective survey

OBJECTIVE

To examine parental experiences during pregnancies affected by Arthrogryposis Multiplex Congenita (AMC) by identifying commonalities, risk factors, and areas for improvement in detection rates, care protocols, and patient experience.

STUDY DESIGN

An online survey was distributed via AMC support groups on Facebook. Topics included demographics, risk factors, parental recall of sonographic findings, delivery characteristics and neonatal findings. Responses were divided into antenatally detected cases (ADCs) and postnatally detected cases (PDCs). Quantitative responses were analyzed with the Fisher exact test. Qualitative data were analyzed with thematic analysis.

RESULTS

The antenatal detection rate of arthrogryposis was 37%. Decreased fetal movement was reported by 53% and early bleeding by 21%. Sonographic findings in ADCs included clubfoot (83%), clenched hand (51%), decreased fetal movement (50%), elbow contracture (51%), and knee contracture (46%). Among ADCs, 29% delivered vaginally and 71% delivered by cesarean versus PDCs (44% vaginal, 56% cesarean). Neonatal intensive care unit admission rate was 63%. Bone fracture occurred in 9%. Detection led to a planned change in delivery mode in 33% and location in 50%. Among ADCs, 17% felt their concerns were not adequately addressed versus 43% of PDCs.

CONCLUSIONS

Antenatal detection of arthrogryposis was low. We propose enhanced screening criteria to aid prenatal diagnosis and promote utilization of more robust practice guidelines.

Éléments de données communs pour l'arthrogrypose multiple congénitale: Un cadre international

Objectif

Afin de faciliter les études multisites et la recherche clinique d'envergure internationale, cette étude a pour but d'identifier des éléments de données communs (EDCs) normalisés et fondés sur un consensus pour l'arthrogrypose multiple congénitale (AMC).

Méthode

Une étude à méthodes mixtes comprenant plusieurs groupes de discussion et trois séries d'enquêtes Delphi modifiées pour parvenir à un consensus ont été menées.

Résultats

Dans l'ensemble, 45 experts cliniques ainsi qu'adultes ayant une expérience vécue (dont 12 membres d'un consortium d'AMC) ont participé à cette étude à travers 11 pays en Amérique du Nord, Europe et Australie. Les EDCs comprennent 321 éléments de données et 19 mesures standardisées dans divers domaines, du développement du fœtus à l'âge adulte. Les éléments de données relatifs aux traits phénotypiques de l'AMC ont été cartographiés conformément à l'ontologie du phénotype humain (HPO). Une structure de gouvernance universelle, des protocoles de fonctionnement et des plans de développement durable ont été identifiés comme les principaux facilitateurs considérant que la capacité limitée de partage des données et la nécessité d'une infrastructure informatique fédérée étaient les principaux obstacles.

Interprétation

Une collecte de données systématiques sur l'AMC à l'aide d'EDCs permettra d'étudier sur les voies étiologiques, décrire le profil épidémiologique, et établir des corrélations génotype‐phénotype de manière standardisée. Les EDCs proposés faciliteront les collaborations internationales multidisciplinaires en améliorant à grande échelle les études multicentriques, les possibilités de partage des données, ainsi que le transfert et la diffusion des connaissances.

Elementos de datos comunes para la artrogriposis múltiple congénita: Un marco internacional

Objetivo

Para facilitar los estudios multicéntricos y la investigación clínica internacional, este estudio pretende identificar de forma consensuada los elementos de datos estandarizados para la artrogriposis múltiple congénita (AMC).

Método

Estudio de métodos mixtos de grupos de discusión y tres rondas de encuestas Delphi modificadas para llegar a un consenso utilizando dos escalas de clasificación por niveles.

Resultados

En total, 45 expertos clínicos y adultos con experiencia vivida (incluidos 12 miembros de un consorcio de AMC) participaron en este estudio procedentes de 11 países: Norteamérica, Europa y Australia. Los CDEs incluyen 321 elementos de datos y 19 medidas estandarizadas en varios dominios desde el desarrollo fetal hasta la edad adulta. Los elementos de datos relativos a los rasgos fenotípicos del CDEs se mapearon de acuerdo con la Ontología de Fenotipos Humanos. Se identificaron como principales facilitadores la estructura de gobernanza universal, protocolos operados de forma local y los planes de sostenibilidad, mientras que los principales obstáculos observados son la capacidad limitada para compartir datos y la necesidad de una infraestructura informática federada.

Interpretación

La recopilación de datos sistemáticos sobre la AMC mediante CDEs permitirá investigar las vías etiológicas, describir el perfil epidemiológico y establecer correlaciones genotipo‐fenotipo de forma estandarizada. Los CDEs propuestos facilitarán las colaboraciones multidisciplinares internacionales mejorando los estudios a gran escala y las oportunidades para compartir datos, translación de conocimiento y difusión.

Common data elements for arthrogryposis multiplex congenita: An international framework

AIM

To facilitate multisite studies and international clinical research, this study aimed to identify consensus-based, standardized common data elements (CDEs) for arthrogryposis multiplex congenita (AMC).

METHOD

A mixed-methods study comprising of several focus group discussions and three rounds of modified Delphi surveys to achieve consensus using two tiered-rating scales were conducted.

RESULTS

Overall, 45 clinical experts and adults with lived experience (including 12 members of an AMC consortium) participated in this study from 11 countries in North America, Europe, and Australia. The CDEs include 321 data elements and 19 standardized measures across various domains from fetal development to adulthood. Data elements pertaining to AMC phenotypic traits were mapped according to the Human Phenotype Ontology. A universal governance structure, local operating protocols, and sustainability plans were identified as the main facilitators, whereas limited capacity for data sharing and the need for a federated informatics infrastructure were the main barriers.

INTERPRETATION

Collection of systematic data on AMC using CDEs will allow investigations on etiological pathways, describe epidemiological profile, and establish genotype-phenotype correlations in a standardized manner. The proposed CDEs will facilitate international multidisciplinary collaborations by improving large-scale studies and opportunities for data sharing, knowledge translation, and dissemination.

Congenital hypotonia: systematic approach for prenatal detection

OBJECTIVES

Congenital hypotonic conditions are rare and heterogeneous, and some are severely debilitating or lethal. Contrary to its prominent postnatal manifestation, the prenatal presentation of hypotonia is frequently subtle, inhibiting prenatal detection. We aimed to characterize the prenatal sonographic manifestation of congenital hypotonia throughout pregnancy, evaluate the yield of diagnostic tests and propose diagnostic models to increase its prenatal detection.

METHODS

This was a retrospective observational study of singleton pregnancies with congenital hypotonia, diagnosed either prenatally or immediately after birth, at a single tertiary center between the years 2012 and 2020. Prenatally, hypotonia was diagnosed if a fetus showed sonographic or clinical signs suggestive of hypotonia and had a confirmed underlying genetic condition, or in the absence of a known genetic abnormality if the fetus exhibited multiple prominent signs suggestive of hypotonia. Postnatally, it was diagnosed in neonates displaying reduced muscle tone leading to reduced spontaneous movement, reduced swallowing or feeding difficulty. We reviewed the medical records of pregnant patients carrying fetuses subsequently diagnosed with congenital hypotonia and assessed the yield of ultrasound scans, fetal magnetic resonance imaging, computed tomography and genetic tests. The detection rate of sonographic signs suggesting fetal hypotonia was calculated. The prevalence of non-specific signs, including polyhydramnios, persistent breech presentation, intrauterine growth restriction and maternal perception of reduced fetal movement, were compared between the study group and the local liveborn singleton population. Potential detection rates of different theoretical semiotic diagnostic models, differing in the threshold for referral for a targeted scan, were assessed based on the cohort's data.

RESULTS

The study group comprised 26 cases of congenital hypotonia, of which 10 (38.5%) were diagnosed prenatally, and the controls included 95 105 singleton live births, giving a prevalence of congenital hypotonia of 1:3658. Nuchal translucency thickness and the early anomaly scan at 13-17 weeks were normal in all 22 and 23 cases, respectively, in which this was performed. The mid-trimester scan performed at 19-25 weeks was abnormal in four of 24 (16.7%) cases. The overall prenatal detection rate of congenital hypotonic conditions in our cohort was 38.5%. Only cases which underwent a targeted scan were detected and, among the 16 cases which underwent this scan, the prenatal detection rate was 62.5% compared with 0% in pregnancies that did not undergo this scan (P = 0.003). An abnormal genetic diagnosis was obtained in 21 (80.8%) cases using the following modalities: chromosomal microarray analysis (CMA) in two (9.5%), whole-exome sequencing (WES) in 14 (66.7%) and methylation analysis in five (23.8%). CMA was abnormal in 8% (2/25) of the cases and WES detected a causative genetic mutation in 87.5% (14/16) of the cases in which these were performed. Comparison of non-specific signs in the study group with those in the local singleton population showed that hypotonic fetuses had significantly more polyhydramnios (64.0% vs 3.0%, P < 0.0001), persistent breech presentation (58.3% vs 4.2%, P < 0.0001), intrauterine growth restriction (30.8% vs 3.0%, P < 0.0001) and maternal perception of reduced fetal movement (32.0% vs 4.7%, P < 0.0001). Prenatally, the most commonly detected signs supporting a diagnosis of hypotonia were structural anomaly (62.5%, 10/16), reduced fetal movement (46.7%, 7/15), joint contractures (46.7%, 7/15) and undescended testes ≥ 30 weeks (42.9%, 3/7 males). Proposed diagnostic strategies that involved performing a targeted scan for a single non-specific ultrasound sign or two such signs, and then carrying out a comprehensive genetic evaluation for any additional sign, offered theoretical detection rates in our cohort of 88.5% and 57.7%, respectively.

CONCLUSIONS

Congenital hypotonic conditions are rare and infrequently detected prenatally. Sonographic signs are visible from the late second trimester. A targeted scan increases prenatal detection significantly. Comprehensive genetic testing, especially WES, is the cornerstone of diagnosis in congenital hypotonia. Theoretical diagnostic models which may increase prenatal detection are provided. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Fetuses and infants with Amyoplasia congenita in congenital Zika syndrome: The evidence of a viral cause. A narrative review of 144 cases

OBJECTIVES

Amyoplasia congenita is the most frequent type of arthrogryposis causing fetal hypokinesia, leading to congenital contractures at birth. The pathogenesis is thought to be impaired blood circulation to the fetus early in pregnancy, with hypotension and hypoxia damaging the anterior horn cells. In animal studies however a prenatal infection with a poliomyelitis-like viral agent was demonstrated. Congenital Zika virus syndrome (CZVS) has recently been described in infants with severe microcephaly, and in 10-25% of cases arthrogryposis.

METHODS

A search in PubMed for CZVS yielded 124 studies. After a selection for arthrogryposis, 35 papers were included, describing 144 cases. The studies were divided into two categories. 1) Those (87 cases) focussing on imaging or histological data of congenital brain defects, contained insufficient information to link arthrogryposis specifically to lesions of the brain or spinal motor neuron. 2) In the other 57 cases detailed clinical data could be linked to neurophysiological, imaging or histological data.

RESULTS

In category 1 the most frequent brain abnormalities in imaging studies were ventriculomegaly, calcifications (subcortical, basal ganglia, cerebellum), hypoplasia of the brainstem and cerebellum, atrophy of the cerebral cortex, migration disorders and corpus callosum anomalies. In category 2, in 38 of 57 cases clinical data were indicative of Amyoplasia congenita. This diagnosis was confirmed by electromyographic findings (13 cases), by MRI (37 cases) or histology (12 cases) of the spinal cord. The latter showed small or absent lateral corticospinal tracts, and cell loss and degeneration of motor neuron cells. Zika virus-proteins and flavivirus-like particles were detected in cytoplasm of spinal neurons.

CONCLUSION

The phenotype of arthrogryposis in CZVS is consistent with Amyoplasia congenita. These findings warrant search for an intrauterine infection with any neurotropic viral agent with affinity to spinal motor neurons in neonates with Amyoplasia.

Epidemiology, aetiology, interventions and genomics in children with arthrogryposis multiplex congenita: protocol for a multisite registry

INTRODUCTION

Arthrogryposis multiplex congenita (AMC) is an umbrella term including hundreds of conditions with the common clinical manifestation of multiple congenital contractures. AMC affects 1 in 3000 live births and is caused by lack of movement in utero. To understand the long-term needs of individuals diagnosed with a rare condition, it is essential to know the prevalence, aetiology and functional outcomes in a large sample. The development and implementation of a multicentre registry is critical to gather this data. This registry aims to improve health through genetic and outcomes research, and ultimately identify new therapeutic targets and diagnostics for treating children with AMC.

METHODS AND ANALYSIS

Participants for the AMC registry will be recruited from seven orthopaedic hospitals in North America. Enrollment occurs in two phases; Part 1 focuses on epidemiology, aetiology and interventions. For this part, retrospective and cross-sectional data will be collected using a combination of patient-reported outcomes and clinical measures. Part 2 focuses on core subset of the study team, including a geneticist and bioinformatician, identifying causative genes and linking the phenotype to genotype via whole genome sequencing to identify genetic variants and correlating these findings with pedigree, photographs and clinical information. Descriptive analyses on the sample of 400 participants and logistic regression models to evaluate relationships between outcomes will be conducted.

ETHICS AND DISSEMINATION

Ethical approval has been granted from corresponding governing bodies in North America. Dissemination of findings will occur via traditional platforms (conferences, manuscripts) for the scientific community. Other modalities will be employed to ensure that all stakeholders, including youth, families and patient support groups, may be provided with findings derived from the registry. Ensuring the findings are circulated to a maximum amount of interested parties will ensure that the registry can continue to serve as a platform for hypothesis-driven research and further advancement for AMC.

Test–retest reliability for performance-based outcome measures among individuals with arthrogryposis multiplex congenita

Background

Most individuals with arthrogryposis multiplex congenita, a rare condition characterized by joint contractures in ≥ 2 body regions, have foot and ankle involvement leading to compromised gait and balance. The purpose of this study was to establish between-days, test–retest reliability for performance-based outcome measures evaluating gait and balance, i.e., the 10-m Walk Test, Figure-of-8 Walk Test, 360-degree Turn Test, and modified Four Square Step Test, among adolescents and adults with arthrogryposis multiplex congenita.

Methods

This reliability study included ambulatory participants, aged 10 to 50 years, with a medical diagnosis of arthrogryposis multiplex congenita. Participants completed performance-based measures, in a randomized order, on two separate occasions. Intraclass correlation coefficients with 95% confidence intervals and minimal detectable changes at the 90% and 95% confidence level were calculated.

Results

Participants included 38 community-ambulators with a median of 13 out of 14 upper and lower joint regions affected. Intraclass correlation coefficient point estimates and 95% confidence intervals ranged from .85-.97 and .70-.98, respectively. Minimal detectable changes were 10 to 39% of sample means and were largest for the modified Four Square Step Test.

Conclusions

Among individuals with arthrogryposis, gait speed per the 10-m Walk Test, as well as non-linear walking and dynamic balance assessment per the Figure-of-8 Walk and 360 Degree Turn Tests, have adequate test–retest reliability enabling evaluation of individual patient changes. Changes in groups of ambulatory individuals with arthrogryposis multiplex congenita may be reliably evaluated with all of the studied outcome measures.

Orthopaedic care of the child with arthrogryposis: a 2020 overview

PURPOSE OF REVIEW

The orthopaedic treatment of children with arthrogryposis multiplex congenita has evolved steadily over the past two decades. Interrelated factors have spurred this on, including better appreciation of the functional potential of persons with arthrogryposis, development of newer procedures specific for the arthrogrypotic deformities, and outcomes studies that provide understanding of the overall capabilities of adults with arthrogryposis and follow-up to determine which treatments were beneficial and which were not. This article briefly sketches out of some of these advances and indicates areas that need further development.

RECENT FINDINGS

Outcome studies show that the majority of adults with arthrogryposis are ambulatory but less than half are fully independent. Adults frequently experience ongoing pain, particularly foot and back pain, limiting ambulation and standing. Advancements in the upper extremity treatment include improving elbow function, wrist repositioning, and improving thumb positioning. In the lower extremities, correction of hip and knee contractures leads to improved ambulatory potential, and treating clubfeet with serial casting decreases poor outcomes.

SUMMARY

Clinical evaluation, both physical examination and assessment of the patient's needs, are important in directing treatment in arthrogryposis. Further outcomes studies are needed to continue to refine procedures and define the appropriate candidates.

Collaborating to advance interdisciplinary care for individuals with arthrogryposis

This Special Issue on Interdisciplinary Care in Arthrogryposis highlights a collection of articles spanning topics in interdisciplinary care, genetic discoveries, and clinical research. An international group of clinicians and researchers from various backgrounds who attended the "3rd International Symposium on Arthrogryposis", held in Philadelphia, September 24-26, 2018, were invited to contribute to this issue. The goal of the 2018 Symposium and of this Special Issue is to provide momentum to advancing evidence-based practice and research in arthrogryposis, by working collaboratively with adults and families of children with arthrogryposis, clinicians, and researchers. The contents of this issue cover a range of topics from defining and classifying arthrogryposis multiplex congenita to early detection, rehabilitation, and orthopedic management, advances in genetic pathways, patient registries, autopsy guidelines, and research findings in the pediatric and adult populations with arthrogryposis. We hope that this issue provides an overview as well as new knowledge on arthrogryposis to generate more conversations at the international level, and advance care and research for individuals with arthrogryposis.

Disease coding systems for arthrogryposis multiplex congenita

Arthrogryposis multiplex congenita (AMC) encompasses many different conditions, involves many different genes and thus can be very complex. Using historical disease coding systems to document syndrome diagnoses and anomalies associated with AMC is often challenging. However, disease coding systems are necessary to provide opportunities for a standard language to be maintained and pertinent data to be identified in the pediatric AMC registry, congenital anomalies surveillance systems, and routine or administrative health information systems. The ICD-10, Orphanet, Online Mendelian Inheritance in Man, and the Human Phenotype Ontology coding and classification systems are described to establish a comprehensive coding strategy. This strategy will provide a necessary tool to contribute to a better understanding of AMC and ultimately improve the health of individuals with AMC.