1/5. Children with mucopolysaccharidoses--three cases report.The mucopolysaccharidoses (MPS) are a group of inherited disorders of metabolism, with widespread, progressive involvement and derangement of many organs and tissues. Because of their disabling nature, frequent surgical intervention for the abnormality entailed is common, and is associated with a high degree of anesthetic risks perioperatively. One of the major hazards which we find clinically is airway difficulty. Multiple factors are present in the mucopolysaccharidoses to make airway management and trachael intubation potentially hazardous. Aside from generalized infiltration and thickening of the soft tissues, the oropharynx may be obstructed by a large tongue with tonsillar hypertrophy. Also, the friable mucosa covering the nasal and oral pharynx renders these structures easily to bleed and edematous. The neck is typically short and immobile, and the cervical spine and tempromandibular joint may have a limited range of movement. From our experience, we have learned not to overlook the propensity of airway difficulty. The uniqueness of their anatomy and extremely sensitive airway often result in failed intubation and bronchospasm even after successful intubation. Recently, in Mackay Memorial Hospital we have encountered in series three pediatric cases with mucopolysaccharidoses (one Hurler and two Hunter syndromes). In this report we would like to share our experiences and to discuss the anesthetic risks and management of the MPS patients.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
2/5. An Alu-mediated rearrangement as cause of exon skipping in Hunter disease.Hunter syndrome (Mucopolysaccharidosis type II), a rare X-linked lysosomal storage disorder, results from deleterious mutations in the iduronate-2-sulfatase ( IDS) gene located on Xq27.3-q28. Partial or complete deletions and large rearrangements have been extensively reported in the IDS gene as the basis of Hunter disease. The present report, however, is the first report on a Hunter patient in which Alu-mediated recombinations are implicated. Our patient showed the skipping of exon 8 at the cDNA level, without any splice-junction defects at the genomic level, where a new large rearrangement was identified instead. This new mutant allele consisted of an extensive deletion of IDS sequence of about 3 kb, as well as an additional inserted sequence of 157 bp. Two different computer programs were necessary to elucidate the nature of the insert. NCBI-BLAST query detected a single match for 126 bp out of 157 of the fragment that aligned exactly with a specific chromosomal region, Xq25-27.1, where an AluSg sequence is adjacent to an L1. Instead, the Repeat Masker program identified only 83 bp out of 157 of the insert, which was confirmed as an AluS. The observed homology between the AluSc sequence in the IDS intron 8 and the inserted AluS element, as well as the closeness of 26 bp Alu core sequence, considered to be a recombination hotspot, made us hypothesise upon the fact that both an Alu retrotransposition and an Alu-mediated deletion underlie the disease-producing rearrangement. We, therefore, now propose a mechanism that led to the large genomic deletion causing the production of the aberrant mRNA splicing.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
3/5. Successful use of nasal-CPAP for obstructive sleep apnea in Hunter syndrome with diffuse airway involvement.A patient with Hunter syndrome and diffuse airway obstruction had daytime hypersomnolence, snoring, and alveolar hypoventilation. polysomnography showed severe obstructive sleep apnea. In the past, all reported cases of sleep apnea in patients with mucopolysaccharidoses had been treated with tonsillectomy/adenoidectomy or tracheostomy. This patient, in whom tracheostomy would have been very difficult due to the diffuse nature of his airway involvement, was successfully treated with high pressure nasal CPAP and supplemental oxygen.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
4/5. Ocular histopathology of systemic mucopolysaccharidosis, type II-A (Hunter syndrome, severe).A case of mucopolysaccharidosis, Type II-A (Hunter syndrome, severe) is described, with emphasis on ocular ultrastructural findings. Single membrane-bound structures containing fibrillogranular and, less commonly, multi-membranous material were found in conjunctival epithelium, pericytes and fibrocytes; corneal epithelium, keratocytes, and endothelium; trabecular endothelium; iris pigmented epithelium, smooth muscle, and fibrocytes; ciliary pigmented and nonpigmented epithelium and fibrocytes; retinal pigment epithelium and ganglion cells; optic nerve astrocytes and pericytes; and sclerocytes. The most striking accumulation was in the nonpigmented ciliary epithelium. These findings are compared with those seen in MPS II-B, and in other systemic mucopolysaccharidoses. The nature and distribution of inclusions are not specific to any one disorder, but help to signal the presence of one of the storage disorders. Distension of corneal keratocytes may play a role in the corneal clouding seen in some of these disorders. The importance of tissue examination, especially conjunctival biopsy, in the diagnosis of storage disorders and in assessment of future modes of therapy for the mucopolysaccharidoses is discussed.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
5/5. hearing loss in Hunter's syndrome--mucopolysaccharidosis ii.Hunter's syndrome [mucopolysaccharidosis ii (MPS II)] is a genetic, metabolic disease of excessive mucopolysaccharide storage leading to mental and skeletal abnormalities, distinctive facial features, and increased incidence of hearing loss. However, the hearing impairment in MPS II has not been well described in the literature. This paper examines the auditory aspects of MPS II by reviewing the literature and by presenting two affected brothers. Each subject had mixed hearing disorders, fluctuating between moderate and severe degrees associated with recurrent middle ear effusions. hearing loss appears to be a frequent concomitant of MPS II and is usually of mixed nature. The conductive component may persist after myringotomy. Aggressive audiological and otological management are required to enhance communicative development.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |