Dear Editor, Mucopolysaccharidosis (MPS) type IVA (Morquio A syndrome) is a lysosomal storage disorder caused by defective degradation of keratan sulfate and chondroitin-6-sulfate, leading to multisystem involvement, especially skeletal abnormalities.1,2 Spinal involvement in Morquio A syndrome occurs at two different sites. Cervical spinal instability and compression, especially at the C1–C2 level, are common and increase the risk of myelopathy, paralysis, and neurogenic bladder.3 A 9-year-old girl, born to non-consanguineous parents with an uneventful antenatal and birth history, presented with a 5-year history of progressive skeletal deformities and a 1-year history of loss of standing and walking ability. She developed gradually worsening lower-limb weakness from the age of 6 years, eventually becoming wheelchair-dependent. There was no family history of hereditary disorders. On examination, she had disproportionate short stature, coarse facial features, a short neck, low hairline, dorsolumbar kyphoscoliosis, pectus carinatum, genu valgum, brittle teeth, wrist hypermobility, and ankle contractures Figure 1. Growth parameters were markedly below the third centile. Neurologically, she was conscious and had normal cognitive ability, but had paraplegia with 0/5 power in the lower limbs, brisk deep tendon reflexes, and ankle clonus, while upper limb strength and sensation were preserved. Laboratory investigations were largely unremarkable. Radiological evaluation showed characteristic features of skeletal dysplasia, including kyphoscoliosis, oar-shaped ribs, osteopenia, fragmented epiphyses, bullet-shaped metacarpals, and a J-shaped sella turcica Figure 2A–D. Magnetic resonance imaging (MRI) of the spine demonstrated platyspondyly, severe spinal canal stenosis at multiple levels, foramen magnum narrowing, and cord compression with myelopathic changes Figure 3. Whole-exome sequencing identified a homozygous missense mutation in the N-acetylgalactosamine 6-sulfatase (GALNS) gene. A diagnosis of MPS type IVA (Morquio A syndrome) with cervical myelopathy was established. Spinal decompression surgery was recommended due to significant cord compression; however, the parents declined intervention because of financial constraints. The nature, progression, and prognosis of the disorder were explained, and supportive care was advised.Figure 1: Female child diagnosed with mucopolysaccharidosis type IVA having coarse facies, a short neck, low hairline, pigeon chest, severe genu valgum, and kyphoscoliosisFigure 2: (A) The radiographs of the spine showing kyphoscoliosis of the lower dorsal spine, oar-shaped ribs, and anterior vertebral beaking. (B) X-ray of the lower limb showing osteopenia along with poorly formed and fragmented femur and epiphyseal ends of the tibia and fibula. (C) X-ray of the wrist showing bullet-shaped metacarpals, medial slanting of metaphyseal ends of the radius, and ulnar bone. (D) X-ray of the skull (lateral view) showing J-shaped sella turcica (red arrow)Figure 3: Magnetic resonance imaging of the whole spine (sagittal view) showing platyspondyly with severe spinal canal stenosis at cervicodorsal levels (C2–C3 green arrow and D10–D11) with foramen magnum stenosis and cord compression with myelopathic changesSpinal canal stenosis is a rare but important complication of MPS type IVA, with limited reported cases.3,4 Affected patients may develop progressive lower-limb weakness, bladder dysfunction, and cervical myelopathy due to spinal cord compression. Atlantoaxial instability from odontoid hypoplasia is the most recognized cervical abnormality, though multilevel stenosis and kyphotic deformities can also be contributing factors.4 Imaging typically shows characteristic vertebral changes with canal narrowing. Early recognition is crucial as surgical decompression and stabilization have been associated with significant neurological improvement and better functional outcomes in several reported cases.5 Progressive cervical myelopathy in Morquio A syndrome results from a complex interplay of spinal canal narrowing, glycosaminoglycan deposition, and progressive skeletal deformity. Vigilant neurological surveillance, timely MRI evaluation, and early surgical decompression when indicated are essential to prevent irreversible spinal cord injury. Declaration of patient consent Written informed consent was obtained from the parents or legal guardians. Ethical policy and Institutional Review Board statement Not applicable. Financial support and sponsorship Nil. Data availability statement Data sharing does not apply to this article as no data sets were generated or analyzed during the current study. Conflicts of interest There are no conflicts of interest. Author contributions NJ was involved in patient management and the review of literature. BKG was involved in the preparation of the draft. BKG did the critical review and will act as the corresponding author/guarantor.
Gaur et al. (Mon,) studied this question.