Respiratory Dysfunction in Children and Adolescents with Mucopolysaccharidosis Types I, II, IVA, and VI.

Assel Tulebayeva,Maira Sharipova,Riza Boranbayeva

doi:10.3390/diagnostics10020063

Assel Tulebayeva, Maira Sharipova + Show 1 more

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https://doi.org/10.3390/diagnostics10020063

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Abstract

Mucopolysaccharidosis (MPS) is a rare genetic disease involving active storage of glycosaminoglycans (GAGs). Accumulation of GAGs in the connective tissues of airways leads to progressive pulmonary dysfunction. Studies conducted in Taiwan revealed mainly restrictive pulmonary dysfunction, whereas the same studies in Egypt and California revealed obstructive pulmonary dysfunction. The contradictory results and lack of studies of respiratory system in patients with MPS in Asian populations are an indication to study pulmonary impairment in patients with MPS in Kazakhstan. The prospective study of respiratory system in patients with MPS was conducted in the Scientific Centre of Paediatrics and Paediatric Surgery. Patients with MPS (n = 11) were examined for respiratory function. Different types of pulmonary dysfunction were present in MPS patients, they were mainly of a restrictive pathology. One patient with MPS II had obstructive dysfunction. Enzyme replacement therapy was provided for an average duration of four years, leading to improvements in respiratory function in two patients with total normalization in one. All observed patients had respiratory dysfunction, mainly of the restrictive type. Pulmonary impairment in patients with MPS is the main reason for death. Thus, it is necessary to follow up with pulmonary function assessments in children with MPS.

Highlights

IntroductionIn patients with MPS, GAGs actively accumulate in connective tissues, leading to progressive multiorgan impairment [2]
Mucopolysaccharidosis (MPS) is a group of genetic disorders, caused by deficiency of lysosomal enzymes involved in the degradation of glycosaminoglycans (GAGs), thereby leading to progressive accumulation of GAGs [1,2] Seven types of MPS exist, and each is characterized by a specific lysosomal enzyme deficiency with the accumulation of different types of GAGs [3]
Impairment of the pulmonary system in patients with MPS is associated with many factors, including the typical morphophenotypes of hypertrophy of the adenoids and tonsils, laryngomalacia, tracheobronchomalacia, obstructive and restrictive lung disease, small chest volume, skeletal deformation, and hepatomegaly

Summary

Introduction

In patients with MPS, GAGs actively accumulate in connective tissues, leading to progressive multiorgan impairment [2]. Mortality in patients with MPS mainly results from progressive pathological processes in the cardiovascular and respiratory systems [4]. Involvement of the respiratory system in the pathological process of MPS has been shown to occur in 56–63% of cases [4,5]. The main cause that predisposes to airway obstruction is active GAG deposition in upper airway tissues, leading to distension of the tongue and hypertrophy of adenoids/tonsils, increased mucoid secretion worsens this situation. Lower respiratory airway collapse usually appears due to laryngomalacia and tracheobronchomalacia as a result of GAG accumulation in the tracheobronchial cartilage. Upper airway dysfunction may result from central nervous system pathology, including hydrocephalus and degeneration of neurons

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