Morquio syndrome

Morquio syndrome

Morquio’s syndrome (referred to as mucopolysaccharidosis IV or Morquio’s) is an autosomal recessive mucopolysaccharide storage disease (see also lysosomal storage disorder), usually inherited.

It is a rare type of birth defect with serious consequences. When the body cannot process certain types of mucopolysaccharides, they build up or are eliminated, causing various symptoms. These involve accumulation of keratan sulfate.

Classification

This syndrome has two forms, A and B, referred to as Morquio A and Morquio B syndrome or MPS IVA and MPS IVB. The two forms are distinguished by the gene product involved; Type A involves a malfunction in the GALNS gene, while Type B involves a malfunction of the GLB1 gene.

Type A GALNS Missing enzyme: Galactosamine-6 sulfatase Chromosomal region: 16q24

Type B GLB1 Missing enzyme: Beta-galactosidase Chromosomal region: 3p22

Treatment

Complications

Atlantoaxial subluxation due to hypoplasia of the odontoid process and joint laxity resulting in myelopathy have been well described in the literature.

Spinal involvement in MPS-IV patients, with neurological impairment, other than atlantoaxial instability and thoracolumbar kyphosis, has been scarcely mentioned in the literature.

Neurological problems secondary to progressive kyphosis and stenosis at the cervicothoracic and upper thoracic spine are seen in children with Morquio syndrome. Early detection with a careful neurological assessment, whole spine MR imaging, and appropriate surgical treatment can prevent permanent neurological sequelae 1).

Case reports

A 17-year-old male patient with severe Morquio syndrome presented with cervical and upper thoracic spinal stenosis with spinal cord myelopathy, and progressive severe tracheal stenosis. Coordinated care among otolaryngology, orthopedic surgery, neurosurgery, anesthesiology, cardiovascular surgery, radiology, and pulmonology teams facilitated the successful planning and execution of two major surgical interventions in rapid succession. This is the first description of a successfully coordinated spine and airway repair in the literature 2).


The records of patients with syndromic Craniovertebral Junction Anomaly treated by Muthukumar during the period of 2012-2017 were retrospectively reviewed. Patients in whom intraoperative difficulties and complications were encountered were culled out from the database. Complications were divided into (1) technique related, (2) neural injury, (3) vascular injury, (4) instrumentation pull out/breakage, (5) screw misplacement and, (6) where postoperatively, the surgeon felt an alternate surgical technique could have yielded better results. Four patients with either unexpected intraoperative difficulties or complications or in whom the technique could have been refined were identified. There were 2 patients with proatlas segmentation anomalies and 2 with Morquio syndrome. The first patient had cage migration which necessitated a second procedure during craniovertebral realignment, the second had partial penetration of the screw into the transverse foramen, the third with bipartite atlas underwent a C1-2 fixation without a horizontal cross-connector and, the fourth had screw pull outs from the subaxial cervical spine intraoperatively during an attempted occipitocervical fusion. In children with syndromic CVJ anomalies, the surgeon should be aware of the high risk of intraoperative difficulties and complications. Potential pitfalls and the ways to avoid these complications are discussed 3).

References

1)

Baratela WA, Bober MB, Thacker MM, Belthur MV, Oto M, Rogers KJ, Mackenzie WG. Cervicothoracic myelopathy in children with morquio syndrome a: a report of 4 cases. J Pediatr Orthop. 2014 Mar;34(2):223-8. doi: 10.1097/BPO.0000000000000074. PubMed PMID: 24096444.
2)

Kiessling P, Stans AA, Dearani JA, Boesch RP, Fogelson JL, Matsumoto JM, Haile DT, Balakrishnan K. Coordinated approach to spinal and tracheal reconstruction in a patient with morquio syndrome. Int J Pediatr Otorhinolaryngol. 2019 Oct 11;128:109721. doi: 10.1016/j.ijporl.2019.109721. [Epub ahead of print] PubMed PMID: 31639621.
3)

Muthukumar N. Problems in Instrumentation of Syndromic Craniovertebral Junction Anomalies – Case Reports. Neurospine. 2019 Jun;16(2):277-285. doi: 10.14245/ns.1938176.088. Epub 2019 Jun 30. PubMed PMID: 31261467.

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