Tracheal and lower airway changes in a patient with mucolipidosis type II

Novel Phenotypical and Biochemical Findings in Mucolipidosis Type II

Mucolipidosis type II is a very rare lysosomal disease affecting the UDP-GlcNAc N-acetylglucosamine-1-phosphotransferase enzyme, which catalyzes the synthesis of the targeting signal mannose 6-phosphate in lysosomal acid hydrolases. Its deficiency hinders the arrival of lysosomal enzymes to the lysosome, diminishing the multiple degradations of components that cells need to perform. Due to the low prevalence of this condition, available information is scarce. This article aims to deepen the understanding of the disease; clinical, biochemical, and proteomic data are analyzed. Three patients have been identified presenting GNPTAB pathogenic variants using whole exome sequencing. A biochemical profile for these patients has been carried out through quantification of glycosaminoglycans in urine samples and enzymatic analysis in dried blood spot (DBS) samples. Quantitative proteomic studies were performed. Results show how enzymatic assays in DBS can be used to diagnose this disease both during the neonatal period or in patients of more advanced age. Increased levels of acid sphingomyelinase, alpha-iduronidase, iduronidate 2-sulfatase, alpha-N-acetyl glucosaminidase, and beta-glucuronidase are found. Conclusion: this biochemical method could potentially improve early diagnosis. Proteomic data supporting these results reveal disrupted biochemical pathways, including the degradation of dermatan sulfate, heparan sulfate, and cellular cholesterol trafficking.

Outcomes after HSCT for mucolipidosis II (I-cell disease) caused by novel compound heterozygous GNPTAB mutations

Background

Mucolipidosis type II (MLII), or I-cell disease, is a rare lysosomal storage disease (LSD) caused by variants in the GNPTAB gene. MLII patients exhibit clinical phenotypes in the prenatal or neonatal stage, such as marked dysmorphic features, cardiac involvement, respiratory symptoms, dysostosis multiplex, severe growth abnormalities, and mental and motor developmental abnormalities. The median age at diagnosis for MLII is 0.7 years, the median survival is 5.0 years, and the median age at death is 1.8 years. No cure for MLII exists.

Methods

Sanger sequencing of the GNPTAB gene identified the compound heterozygous mutations c.673C > T in exon 7 and c.1090C > T in exon 9, which were novel double heterozygous mutations first reported in China. For the first time, we describe our experience in the use of HSCT for MLII. Our patient underwent HSCT with cells from a 9/10 human leukocyte antigen (HLA)-matched unrelated donor at 12 months of age. Myeloid neutrophil and platelet engraftment occurred on Days 10 and 11, respectively.

Results

The patient's limb muscle tension was significantly reduced, and his gross and fine motor skills were improved four months after transplantation. DST(Developmental Screen Test) results showed that the patient's fine motor skills and mental development were improved compared with before HSCT.

Conclusion

MLII is a very severe lysosomal storage disease, to date, only 3 cases have been reported on the use of HSCT to treat MLII. Our data show that HSCT is a potential way to prolong the life of patients and improve their quality of life. Due to the lack of comparable data and time, the exact benefit remains unclear in MLII patients. Longer-term follow-up and in-depth prospective studies are indispensable.

Unexpected difficult airway due to severe upper tracheal distortion: A case report

BACKGROUND

Difficult airway is a significant cause of anesthesia-associated death and disability. Currently, physical examinations of thyromental distance, mouth opening, Mafampaii classification, etc. combined with X-ray, computed tomography (CT), and other imaging technologies are mainly used to evaluate difficult airways. However, in many special cases, i.e., emergency surgery, imaging examinations cannot be completed preoperatively. Such patients' airway can only be evaluated through general physical examination, which inevitably increases the likelihood of an unexpected difficult airway during anesthesia.

CASE SUMMARY

We report a rare case of difficult intubation because of severe upper trachea distortion after induction. Emergency holmium laser lithotripsy was performed under transurethral ureteroscopy because the patient had anuria for 4 d and a creatinine level of 890 μmol/L. Due to the urgency of the condition, chest radiography or chest CT was not examined before surgery and the anesthesiologist did not evaluate the airway adequately, resulting in an unexpected difficult airway.

CONCLUSION

The incidence of tracheal malformation and tracheal stenosis is extremely low, but the risk of hypoxia and even death due to difficult airways is extremely high for such patients. It is recommended to complete preoperative imaging examinations of the airway. For life-threatening emergency patients, a pre-anesthesia reassessment should be performed and surgeons should be prepared to prevent and manage the difficult airway.

Anaesthesia-Relevant Disease Manifestations and Perianaesthetic Complications in Patients with Mucolipidosis—A Retrospective Analysis of 44 Anaesthetic Cases in 12 Patients

Mucolipidosis (ML) type II, intermediate, and III are lysosomal storage disorders with progressive multiorgan manifestations predisposing patients to a high risk of perioperative morbidity. The aims of the study were to systematically assess disease manifestations relevant to anaesthesia as well as anaesthesia-related complications. This retrospective study includes ML patients who underwent anaesthesia in two centres between 2008 and 2022. We reviewed patients’ demographics, medical history, disease manifestations, as well as procedure- and outcome-related data. A total of 12 patients (7 MLII, 2 ML intermediate, 3 MLIII) underwent 44 anaesthesia procedures (per patient: median 3, range 1–11). The median age was 3.3 years (range 0.1–19.1). At least one complication occurred in 27.3% of the anaesthesia procedures. The vast majority of complications (94%) occurred in children with MLII and ML intermediate. A predicted difficult airway was found in 100% and 80% of the MLII and ML intermediate patients, respectively. Accordingly, most complications (59%) occurred during the induction of anaesthesia. Altogether, respiratory complications were the most frequent (18%), followed by difficult airway management (14%). The risk for anaesthesia-related complications is alarmingly high in patients with ML, particularly in those with MLII and ML intermediate. Multidisciplinary risk–benefit analysis and thoughtful anaesthesia planning are crucial in these patients.