Orthopaedic phenotyping of NGLY1 deficiency using an international, family-led disease registry

Abstract Background NGLY1 deficiency is a rare autosomal recessive disorder caused by loss in enzymatic function of NGLY1, a peptide N-glycanase that has been shown to play a role in endoplasmic reticulum associated degradation (ERAD). ERAD dysfunction has been implicated in other well-described pro...

Full description

Bibliographic Details
Main Authors: Eli M. Cahan, Steven L. Frick
Format: Article
Language:English
Published: BMC 2019-06-01
Series:Orphanet Journal of Rare Diseases
Subjects:
Online Access:http://link.springer.com/article/10.1186/s13023-019-1131-4
_version_ 1818127664040378368
author Eli M. Cahan
Steven L. Frick
author_facet Eli M. Cahan
Steven L. Frick
author_sort Eli M. Cahan
collection DOAJ
description Abstract Background NGLY1 deficiency is a rare autosomal recessive disorder caused by loss in enzymatic function of NGLY1, a peptide N-glycanase that has been shown to play a role in endoplasmic reticulum associated degradation (ERAD). ERAD dysfunction has been implicated in other well-described proteinopathies, such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease. The classical clinical tetrad includes developmental delay, hypolacrima, transiently elevated transaminases, and hyperkinetic movement disorders. The musculoskeletal system is also commonly affected, but the orthopaedic phenotype has been incompletely characterized. Best practices for orthopaedic clinical care have not been elucidated and considerable variability has resulted from this lack of evidence base. Our study surveyed patients enrolled in an international registry for NGLY1 deficiency in order to characterize the orthopaedic manifestations, sequelae, and management. Results Our findings, encompassing the largest cohort for NGLY1 deficiency to date, detail levels of motor milestone achievement; physical exam findings; fracture rates/distribution; frequency of motor skill regression; non-pharmacologic and non-procedural interventions; pharmacologic therapies; and procedural interventions experienced by 29 participants. Regarding the orthopaedic phenotype, at time of survey response, we found that over 40% of patients experienced motor skill regression from their peak. Over 80% of patients had at least one orthopaedic diagnosis, and nearly two-thirds of the total had two or more. More than half of patients older than 6 years had sustained a fracture. Related to orthopaedic non-medical management, we found that 93 and 79% of patients had utilized physical therapy and non-operative orthoses, respectively. In turn, the vast majority took at least one medication (including for bone health and antispasmodic therapy). Finally, nearly half of patients had undergone an invasive procedure. Of those older than 6 years, two-thirds had one or more procedures. Stratification of these analyses by sex revealed distinctive differences in disease natural history and clinical management course. Conclusions These findings describing the orthopaedic natural history and standard of care in patients with NGLY1 deficiency can facilitate diagnosis, inform prognosis, and guide treatment recommendations in an evidence-based manner. Furthermore, the methodology is notable for its partnership with a disease-specific advocacy organization and may be generalizable to other rare disease populations. This study fills a void in the existing literature for this population and this methodology offers a precedent upon which future studies for rare diseases can build.
first_indexed 2024-12-11T07:20:57Z
format Article
id doaj.art-5a8750ebac1144dca72ec14b73cc83dc
institution Directory Open Access Journal
issn 1750-1172
language English
last_indexed 2024-12-11T07:20:57Z
publishDate 2019-06-01
publisher BMC
record_format Article
series Orphanet Journal of Rare Diseases
spelling doaj.art-5a8750ebac1144dca72ec14b73cc83dc2022-12-22T01:16:05ZengBMCOrphanet Journal of Rare Diseases1750-11722019-06-011411810.1186/s13023-019-1131-4Orthopaedic phenotyping of NGLY1 deficiency using an international, family-led disease registryEli M. Cahan0Steven L. Frick1New York University School of MedicineDepartment of Pediatric Orthopaedics, Stanford UniversityAbstract Background NGLY1 deficiency is a rare autosomal recessive disorder caused by loss in enzymatic function of NGLY1, a peptide N-glycanase that has been shown to play a role in endoplasmic reticulum associated degradation (ERAD). ERAD dysfunction has been implicated in other well-described proteinopathies, such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease. The classical clinical tetrad includes developmental delay, hypolacrima, transiently elevated transaminases, and hyperkinetic movement disorders. The musculoskeletal system is also commonly affected, but the orthopaedic phenotype has been incompletely characterized. Best practices for orthopaedic clinical care have not been elucidated and considerable variability has resulted from this lack of evidence base. Our study surveyed patients enrolled in an international registry for NGLY1 deficiency in order to characterize the orthopaedic manifestations, sequelae, and management. Results Our findings, encompassing the largest cohort for NGLY1 deficiency to date, detail levels of motor milestone achievement; physical exam findings; fracture rates/distribution; frequency of motor skill regression; non-pharmacologic and non-procedural interventions; pharmacologic therapies; and procedural interventions experienced by 29 participants. Regarding the orthopaedic phenotype, at time of survey response, we found that over 40% of patients experienced motor skill regression from their peak. Over 80% of patients had at least one orthopaedic diagnosis, and nearly two-thirds of the total had two or more. More than half of patients older than 6 years had sustained a fracture. Related to orthopaedic non-medical management, we found that 93 and 79% of patients had utilized physical therapy and non-operative orthoses, respectively. In turn, the vast majority took at least one medication (including for bone health and antispasmodic therapy). Finally, nearly half of patients had undergone an invasive procedure. Of those older than 6 years, two-thirds had one or more procedures. Stratification of these analyses by sex revealed distinctive differences in disease natural history and clinical management course. Conclusions These findings describing the orthopaedic natural history and standard of care in patients with NGLY1 deficiency can facilitate diagnosis, inform prognosis, and guide treatment recommendations in an evidence-based manner. Furthermore, the methodology is notable for its partnership with a disease-specific advocacy organization and may be generalizable to other rare disease populations. This study fills a void in the existing literature for this population and this methodology offers a precedent upon which future studies for rare diseases can build.http://link.springer.com/article/10.1186/s13023-019-1131-4NGLY1 deficiencyOrthopaedicsNatural historyStandard of careDisease advocacy organizationsEvidence-based medicine
spellingShingle Eli M. Cahan
Steven L. Frick
Orthopaedic phenotyping of NGLY1 deficiency using an international, family-led disease registry
Orphanet Journal of Rare Diseases
NGLY1 deficiency
Orthopaedics
Natural history
Standard of care
Disease advocacy organizations
Evidence-based medicine
title Orthopaedic phenotyping of NGLY1 deficiency using an international, family-led disease registry
title_full Orthopaedic phenotyping of NGLY1 deficiency using an international, family-led disease registry
title_fullStr Orthopaedic phenotyping of NGLY1 deficiency using an international, family-led disease registry
title_full_unstemmed Orthopaedic phenotyping of NGLY1 deficiency using an international, family-led disease registry
title_short Orthopaedic phenotyping of NGLY1 deficiency using an international, family-led disease registry
title_sort orthopaedic phenotyping of ngly1 deficiency using an international family led disease registry
topic NGLY1 deficiency
Orthopaedics
Natural history
Standard of care
Disease advocacy organizations
Evidence-based medicine
url http://link.springer.com/article/10.1186/s13023-019-1131-4
work_keys_str_mv AT elimcahan orthopaedicphenotypingofngly1deficiencyusinganinternationalfamilyleddiseaseregistry
AT stevenlfrick orthopaedicphenotypingofngly1deficiencyusinganinternationalfamilyleddiseaseregistry