Dens Growth After Surgical Fixation in Children with Morquio-Brailsford Disease.

Mucopolysaccharidosis type IVA is a lysosomal storage disorder caused by a deficiency of the enzyme N-acetyl-galactosamine-6-sulphate sulphatase. Mucopolysaccharidosis type IVA is multisystemic disease with significant spinal involvement and atlantoaxial instability leading to neural compression and significant morbidity. Dens hypoplasia is a common feature of this condition. In this study we demonstrate that after spinal fixation, there is new growth of dens in significant proportion of patients, suggesting atlantoaxial instability as one of the major driving forces of lack of development of dens in this condition.

Tracheal Narrowing and Its Impact on Anesthesia Care in Patients With Morquio A (Mucopolysaccharidosis Type IVA): An Observational Study.

BACKGROUND: Recently, tracheal narrowing has been recognized as a significant comorbid condition in patients with Morquio A, also known as mucopolysaccharidosis IVA. We studied a large cohort of patients with Morquio A to describe the extent of their tracheal narrowing and its relationship to airway management during anesthesia care. METHODS: This is an observational study, collecting data retrospectively, of a cohort of patients with Morquio A. Ninety-two patients with Morquio A syndrome were enrolled, among whom 44 patients had their airway evaluated by computed tomography angiography and had undergone an anesthetic within a year of the evaluation. Our hypothesis was that the tracheal narrowing as evaluated by computed tomography angiography increases with age in patients with Morquio A. The primary aim of the study was to examine the degree of tracheal narrowing in patients with Morquio A and describe the difficulties encountered during airway management, thus increasing awareness of both the tracheal narrowing and airway management difficulties in this patient population. In addition, the degree of tracheal narrowing was evaluated for its association with age or spirometry parameters using Spearman's rank correlation. Analysis of variance followed by the Bonferroni test was used to further examine the age-based differences in tracheal narrowing for the 3 age groups: 1 to 10 years, 11 to 20 years, and >21 years. RESULTS: Patient age showed a positive correlation with tracheal narrowing ( rs= 0.415; 95% confidence interval [95% CI], 0.138-0.691; P = .005) with older patients having greater narrowing of the trachea. Among spirometry parameters, FEF25%-75% showed an inverse correlation with tracheal narrowing as follows: FEF25%-75% versus tracheal narrowing: ( rs = -0.467; 95% CI, -0.877 to -0.057; P = .007). During anesthetic care, significant airway management difficulties were encountered, including cancelation of surgical procedures, awake intubation using flexible bronchoscope, and failed video laryngoscopy attempts. CONCLUSIONS: Clinically significant tracheal narrowing was present in patients with Morquio A, and the degree of such narrowing likely contributed to the difficulty with airway management during their anesthetic care. Tracheal narrowing worsens with age, but the progression appears to slow down after 20 years of age. In addition to tracheal narrowing, spirometry values of FEF25%-75% may be helpful in the overall evaluation of the airway in patients with Morquio A.

Posterior Atlantoaxial Fusion With C1-2 Pedicle Screw Fixation for Atlantoaxial Dislocation in Pediatric Patients With Mucopolysaccharidosis IVA (Morquio a Syndrome): A Case Series.

OBJECTIVE: To investigate the efficacy and safety of posterior atlantoaxial fusion (AAF) with C1-2 pedicle screw fixation for atlantoaxial dislocation (AAD) in pediatric patients with mucopolysaccharidosis IVA (MPS IVA). METHODS: This study included 21 pediatric patients with MPS IVA who underwent posterior AAF with C1-2 pedicle screw fixation. Anatomical parameters of the C1 and C2 pedicle were measured on preoperative computed tomography (CT). The American Spinal Injury Association (ASIA) scale was used to evaluate the neurological status. The fusion and accuracy of pedicle screw was assessed on postoperative CT. Demographic, radiation dose, bone density, surgical, and clinical data were recorded. RESULTS: Patients reviewed included 21 patients younger than 16 years with an average age of 7.4 ± 4.2 years and an average of 20.9 ± 7.7 months follow-up. Fixation of 83 C1 and C2 pedicle screws was performed successfully and 96.3% of them were identified as being safe. One patient developed postoperative transient disturbance of consciousness and one developed fetal airway obstruction and died about 1 month after the surgery. Out of the remaining20 patients, fusion was achieved, symptoms were improved, and no other serious surgical complications were observed at the latest follow-up. CONCLUSIONS: Posterior AAF with C1-2 pedicle screw fixation is effective and safe for AAD in pediatric patients with MPS IVA. However, the procedure is technically demanding and should be performed by experienced surgeons with strict multidisciplinary consultations.

Manejo anestésico de una gestante con síndrome de Morquio / Anesthetic Management for a pregnant woman with Morquio syndrome Sobre los autores:

Introducción: El síndrome de Morquio es una enfermedad hereditaria autosómica recesiva con distintos grados de afectación al metabolismo de los glúcidos, lo que genera incapacidad para romper los enlaces de las cadenas largas de glucosamiglicanos, esto provoca acumulación de mucopolisacáridos en distintos tejidos del cuerpo humano. Objetivo: Describir el manejo anestésico de una gestante con síndrome de Morquio. Presentación del caso: Gestante primigesta de 30 años de edad, de raza negra, de 103 cm de estatura y 33 Kg de peso. Acude a consulta preoperatoria por presentar embarazo a término, baja talla y se realizó interrupción del embarazo por vía alta. Se procede a la valoración preanestésica donde se recoge antecedentes de enfermedad genética e ingreso previo por presentar cifras elevadas de tensión arterial. La paciente padecía de alergia a la dipirona. Conclusiones: Los pacientes con mucopolisacaridosis tienen una alta incidencia de dificultad para la ventilación y la intubación endotraqueal asociada con insuficiencia cardiopulmonar. La afectación de la columna presenta dificultades adicionales para los anestesiólogos. Cualquier cirugía electiva requiere una evaluación preoperatoria de los factores de riesgo anestesiológicos y la disponibilidad de un espectro de equipos para el manejo de las vías respiratorias. La anestesia debe ser realizada por un equipo con experiencia en el manejo de la vía aérea(AU)

Introduction: Morquio syndrome is an autosomal recessive hereditary disease that affects, to different extents, carbohydrate metabolism, which obstructs the ability to break bonds of long chains of glycosaminoglycans, causing mucopolysaccharides accumulation in different tissues of the human body. Objective: To describe the anesthetic management of a pregnant woman with Morquio syndrome. Case presentation: This is the case of a 30-year-old primigravid pregnant woman, of black skin, 103 cm of height and 33 kg of weight. She came for preoperative consultation because she was pregnant at term and had low body size; the pregnancy was terminated through the abdominal route. A preanesthetic assessment was performed, which permitted to observe a history of genetic disease and previous admission for high blood pressure. The patient was allergic to dipyrone. Conclusions: Among patients with mucopolysaccharidosis, there is a high incidence of difficulty for ventilation and endotracheal intubation associated with cardiopulmonary insufficiency. Spinal involvement represents additional difficulties for anesthesiologists. Any elective surgery requires preoperative assessment of anesthesiologic risk factors and the availability of a spectrum of airway management equipment. Anesthetic managment should be performed by a team experienced in airway management(AU)

Airway Management of the Deformed Trachea Using T-Tube Stents in Patients with Mucopolysaccharidosis Type IVA.

INTRODUCTION: Mucopolysaccharidosis (MPS) type IVA usually results in airway obstruction due to thoracic cage deformity and crowding of intrathoracic structures, causing tracheal compression by the tortuous innominate artery. OBJECTIVES: To offer an alternative and effective method in dealing with the challenged deformity of the airway in patients with MPS type IVA. METHODS: We present 3 patients with MPS type IVA who underwent airway stenting using Montgomery® T-tube stents. Three-dimensional reconstructed computed tomography was essential to design the T-tube and evaluate the anatomical relationship between the innominate artery and the trachea. The Y-shaped Montgomery® Pediatric Safe-T-Tube™ is more suitable for MPS type IVA. Regular follow-ups using fiberoptic bronchoscopy are necessary to evaluate the complications. RESULTS: All 3 patients had good outcomes during the follow-ups until present, despite the complication of granulation formation, which was resolved by revising the limbs of the T-tube. CONCLUSIONS: T-tube stents placed below the vocal cord may restore airway patency and preserve laryngeal function, including respiration, phonation, and swallowing, in patients with MPS type IVA.

Adult Morquio syndrome requiring occipito-thoracic fusion.

Morquio syndrome is a relatively rare entity that is often associated with atlantoaxial instability from early childhood due to odontoid dysplasia based on a mucopolysaccharoidal disorder. Here, we present the case of a 55-year-old male patient with Morquio syndrome who developed cervical myelopathy, which is an extremely rare condition in the older population. Myelopathy developed gradually with upper-limb paresthesia and clumsiness of both hands. The patient had a characteristic "gargoyle-like" coarse face with a trunk shortening-type short stature. Imaging of the cervical spine demonstrated several problems, including diminutive structures called platyspondyly with small pedicles and fragile bone quality, hypoplasia of the C1 posterior arch that migrated into the spinal canal, and os odontoideum with atlantoaxial instability. With intraoperative navigation guidance, posterior decompression of C1 followed by occipito-cervico-thoracic spinal fusion was successfully performed in this complicated case. Clinical and radiographic outcomes were both excellent and have been maintained for 2 years postoperatively.

Coordinated approach to spinal and tracheal reconstruction in a patient with morquio syndrome.

Morquio syndrome (Mucopolysaccharidosis IVA) is an autosomal recessive lysosomal storage disease with manifestations ranging from mild to severe phenotype. Mechanical spinal cord injury and airway insufficiency are major causes of mortality. 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 successful coordinated spine and airway repair in the literature.

Outcomes from 18 years of cervical spine surgery in MPS IVA: a single centre's experience.

PURPOSE: This study examines the long-term outcomes of paediatric Morquio (MPS IVA) patients undergoing cervical spine surgery and evaluates the factors that impacting this. METHODS: A retrospective review was performed on all MPS IVA patients undergoing cervical spine surgery, since the introduction of standardised neuroradiological screening. The impact of preoperative neurological status, growth, genotype and radiological status on outcome is assessed, whilst long-term surgical, radiological and neurological outcomes are documented. RESULTS: Twenty-six of the eighty-two MPS IVA patients (31%) reviewed underwent cervical spine surgery at a median age of 6.1 years (range, 1.45 to 15.24). Preoperatively, cord signal change was seen in 11 patients with 5 being myelopathic; however, 6 clinically manifesting patients had no overt cord signal change. Postoperatively, none of the 14 preoperatively clinically asymptomatic patients followed long term progressed neurologically during a median follow-up of 77.5 months (range = 18-161). Of the ten preoperatively clinically symptomatic patients who were followed up for the same duration, seven continued to deteriorate, two initially improved and one remained stable. Radiological follow-up performed for a median duration of 7 years (range = 0.5-16) has shown a degree of stenosis at the level immediately caudal to the termination of the graft in 76% of patients, though only one has become clinically symptomatic and required revision. CONCLUSIONS: Once clinically elicitable neurological signs become evident in patients with MPS IVA, they tend to progress despite surgical intervention. Referring clinicians should also not be falsely reassured by the lack of T2 spinal cord signal change but should consider surgical intervention in the face of new clinical symptomology or radiological signs of progressive canal stenosis or instability.

Spine malformation complex in 3 diverse syndromic entities: Case reports.

RATIONALE: Clinical and radiographic phenotypic characterizations were the base line tool of diagnosis in 3 syndromic disorders in which congenital cervico-thoracic kyphosis was the major deformity. PATIENTS CONCERNS: Directing maximal care toward the radiographic analysis is not only the axial malformation but also toward the appendicular abnormalities was our main concern. We fully documented the diversity of the spine phenotypic malformation complex via the clinical and radiographic phenotypes. DIAGNOSES: We established the diagnosis via phenotypic/genotypic confirmation in 3 diverse syndromic entities namely acampomelic campomelic dysplasia, Larsen syndrome and Morquio syndrome type A (mucopolysaccharidosis type IV A). INTERVENTIONS: Surgical interventions have been carried out in the Larsen syndrome and Morquio syndrome type A, resepectively. OUTCOMES: The earliest the diagnosis is, the better the results are. The necessity to diagnose children in their first year of life has many folds, firstly the management would be in favor of the child's growth and development and secondly, the prognosis could be clearer to the family and the medical staff as well. Our current paper is to sensitize paediatricians, physicians and orthopedic surgeons regarding the necessity to detect the aetiological understanding in every child who manifests a constellation of malformation complex. LESONS: Scoliosis and kyphosis/kyphoscoliosis are not a diagnosis in themselves. Such deformities are mostly a symptom complex correlated to dozens of types of syndromic associations. The rate curve progression and the final severity of congenital spine tilting are related to 3 factors: (a) the type of vertebral malformation present, (b) the patient's phenotype, and

Corrections of diverse forms of lower limb deformities in patients with mucopolysaccharidosis type IVA (Morquio syndrome).

BACKGROUND: Thoracolumbar kyphosis has been considered as the first presenting deformity and is often a key diagnostic clue noted in children with mucopolysaccharidosis (MPS) type IV (Morquio's syndrome). However, we observed that the progressive irregularities of the epiphyses of the long bones were the most prominent skeletal pathology, causing effectively the development of diverse forms of lower limbs deformities with extreme variation in age of onset. MATERIALS AND METHODS: Ten patients (seven children and three adults) with an average age of 15 years have been enrolled in this study. Age of diagnosis of MPS IVA has a variable age of onset and a MISLEADING rate of severity. Hip dislocations, genu valgum, protrusio acetabuli and osteoarthritis were the most common lower limbs deformities in these patients. Clinical and radiographic phenotypes were the baseline tools of documentation. Urinary screening and genotypic characterizations have been applied accordingly. RESULTS: Combined pelvic and femoral procedures for hip dislocation, epiphysiodeses and supracondylar osteotomy for genu valgum and hip arthroplasty for protrusio acetabuli have been performed. All patients manifested insufficient activity of N-acetylgalactosamine-6-sulphate sulphatase, an enzyme that degrades keratin sulphate and chondroitin-6 sulphate. CONCLUSION: The extensive clinical heterogeneity contributed significantly in the delay in establishing the diagnosis particularly in adult patients with MPS IV. The epiphyseal irregularities of the long bones and the progressive flattening pathology of MPS IV A were the reason to falsely diagnose some patients as spondyloepiphyseal dysplasia congenital and/or tarda. Proximal femoral osteotomy, realignment osteotomy and total hip arthroplasty have been performed for coxa vara, genu valgum and protrusio acetabuli, respectively, in children and adult group of patients. The importance of early diagnosis on MPS IV A is to receive enzyme replacement therapy and plan for other therapeutic measures.

Activity of daily living for Morquio A syndrome.

The aim of this study was to evaluate the activity of daily living (ADL) and surgical interventions in patients with mucopolysaccharidosis IVA (MPS IVA). The factor(s) that affect ADL are age, clinical phenotypes, surgical interventions, therapeutic effect, and body mass index. The ADL questionnaire comprises three domains: "Movement," "Movement with cognition," and "Cognition." Each domain has four subcategories rated on a 5-point scale based on the level of assistance. The questionnaire was collected from 145 healthy controls and 82 patients with MPS IVA. The patient cohort consisted of 63 severe and 17 attenuated phenotypes (2 were undefined); 4 patients treated with hematopoietic stem cell transplantation (HSCT), 33 patients treated with enzyme replacement therapy (ERT) for more than a year, and 45 untreated patients. MPS IVA patients show a decline in ADL scores after 10years of age. Patients with a severe phenotype have a lower ADL score than healthy control subjects, and lower scores than patients with an attenuated phenotype in domains of "Movement" and "Movement with cognition." Patients, who underwent HSCT and were followed up for over 10years, had higher ADL scores and fewer surgical interventions than untreated patients. ADL scores for ERT patients (2.5years follow-up on average) were similar with the-age-matched controls below 10years of age, but declined in older patients. Surgical frequency was higher for severe phenotypic patients than attenuated ones. Surgical frequency for patients treated with ERT was not decreased compared to untreated patients. In conclusion, we have shown the utility of the proposed ADL questionnaire and frequency of surgical interventions in patients with MPS IVA to evaluate the clinical severity and therapeutic efficacy compared with age-matched controls.

Management of labor and delivery in a woman with Morquio syndrome.

Morquio syndrome, a congenital mucopolysaccharidosis, presents several challenges for the provision of effective labor analgesia. We report the case of a woman admitted for induction of labor who received an early epidural and subsequently required cesarean delivery. Optimal bilateral labor analgesia was not achieved despite multiple adjustments, and systemic analgesia was needed for cesarean delivery.

Paraplegia after epidural-general anesthesia in a Morquio patient with moderate thoracic spinal stenosis.

PURPOSE: We describe an instance in which complete paraplegia was evident immediately postoperatively after apparently uneventful lumbar epidural-general anesthesia in a patient with Morquio Type A syndrome (Morquio A) with moderate thoracic spinal stenosis. CLINICAL FEATURES: A 16-yr-old male with Morquio A received lumbar epidural-general anesthesia for bilateral distal femoral osteotomies. Preoperative imaging had revealed a stable cervical spine and moderate thoracic spinal stenosis with a mild degree of spinal cord compression. Systolic blood pressure (BP) was maintained within 20% of the pre-anesthetic baseline value. The patient sustained a severe thoracic spinal cord infarction. The epidural anesthetic contributed to considerable delay in the recognition of the diagnosis of paraplegia. CONCLUSION: This experience leads us to suggest that, in patients with Morquio A, it may be prudent to avoid the use of epidural anesthesia without very firm indication, to support BP at or near baseline levels in the presence of even moderate spinal stenosis, and to avoid flexion or extension of the spinal column in intraoperative positioning. If the spinal cord/column status is unknown or if the patient is known to have any degree of spinal stenosis, we suggest that the same rigorous BP support practices that are typically applied in other patients with severe spinal stenosis, especially stenosis with myelomalacia, should apply to patients with Morquio A and that spinal cord neurophysiological monitoring should be employed. In the event that cord imaging is not available, e.g., emergency procedures, it would be prudent to assume the presence of spinal stenosis.

Inestabilidad occipitocervical en la enfermedad de Morquio. Presentación de 2 casos y revisión de la literatura / Occipital-cervical instability in Morquio disease: a presentation of 2 cases and a review of the literature

Introducción. El síndrome de Morquio se produce por un déficit enzimático de herencia autosómica recesiva. Presenta numerosas manifestaciones musculoesqueléticas, entre las que destaca por su riesgo vital la inestabilidad atloaxoidea. En estos casos está indicada la cirugía de artrodesis (y descompresión) occipitocervical Objetivo. Se presentan 2 pacientes con síndrome de Morquio que precisaron de este tipo de cirugía, así como una revisión de la literatura. Pacientes y métodos. Dos pacientes: un niño y una niña, con síndrome de Morquio e inestabilidad cervical alta, con signos y síntomas neurológicos, que fueron intervenidos quirúrgicamente mediante descompresión y artrodesiso occipitocervical instrumentada; con un seguimiento de 6 y un año respectivamente. Resultados. Ambos pacientes mejoraron de sus problemas neurológicos, realizando en al actualidad una vida normal para su edad. Conclusión. La artrodesis occipitocervical con descompresión proporciona un entorno biomecánico seguro que previene de la afectación neurológica. Estaría indicada ante la aparición de sintomatología o de inestabilidad mecánica (AU)

Introduction. Morquio syndrome is caused by an inherited autosomal recessive enzyme deficiency. It presents with numerous musculoskeletal anomalies, among which atlantoaxial instability is highlighted, due it being life-threatening. Occipital-cervical arthrodesis surgery (and decompression) is indicated in these cases. Objective. The cases of 2 patients with Morquio syndrome that required this type of surgery are presented, along with a review of the literature. Patients and methods. Two patients: one boy and one girl, with Morquio syndrome and high cervical instability, with neurological signs and symptoms, who were subjected to surgery using decompression and instrumented occipital-cervical arthrodesis and followed up for 6 months and one year, respectively. Results. The neurological problems of both patients improved, and are currently having a normal life for their age. Conclusion. Occipital-cervical arthrodesis with decompression provides a safe biomechanical environment that prevents neurological involvement. It should be indicated before the appearance of symptoms or mechanical instability (AU)

Morquio A syndrome: diagnosis and current and future therapies.

Morquio A syndrome is an autosomal recessive disorder, one of 50 lysosomal storage diseases (LSDs), and is caused by the deficiency of N-acetylgalactosamine-6-sulfate sulfatase (GALNS). Deficiency of this enzyme causes specific glycosaminoglycan (GAG) accumulation: keratan sulfate (KS) and chondroitin-6-sulfate (C6S). The majority of KS is produced in the cartilage, therefore, the undegraded substrates accumulate mainly in cartilage and in its extracelluar matrix (ECM), causing direct leads to direct impact on cartilage and bone development and leading to the resultant systemic skeletal spondyloepiphyseal dysplasia. Chondrogenesis ,the earliest phase of skeletal formation that leads to cartilage and bone formation is controlled by cellular interactions with the ECM, growth and differentiation factors and other molecules that affect signaling pathways and transcription factors in a temporal-spatial manner. In Morquio A patients, in early childhood or even at birth, the cartilage is disrupted presumably as a result of abnormal chondrogenesis and/ or endochondral ossification. The unique clinical features are characterized by a marked short stature, odontoid hypoplasia, protrusion of the chest, kyphoscoliosis, platyspondyly, coxa valga, abnormal gait, and laxity of joints. In spite of many descriptions of the unique clinical manifestations, diagnosis delay still occurs. The pathogenesis of systemic skeletal dysplasia in Morquio A syndrome remains an enigmatic challenge. In this review article, screening, diagnosis, pathogenesis and current and future therapies of Morquio A are discussed.

Occipitocervical fusion in skeletal dysplasia: a new surgical technique.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: This study describes clinical and radiological results of a new cable technique for occipitocervical fusion (OCF) in children with skeletal dysplasia (SD). SUMMARY OF BACKGROUND DATA: Anatomical variability and poor bone quality make upper cervical surgery technically challenging in patients with SD. We present a new cable technique for OCF in children with SD when the posterior elements are not of a size or quality for other types of instrumentation. METHODS: Retrospective review of 24 patients with SD (8 boys, 16 girls) who underwent OCF between 2001 and 2011. In this technique, cables provide compression across a bone graft that is prevented from entering the canal and the graft resists excessive lordosis. Demographic and radiographical data are presented. All patients were followed for initial outcomes of surgery, and 20 patients (83%) were followed for 2 years or more for mid- and long-term outcomes. RESULTS: Mean age at surgery was 6.5 years and mean follow-up was 4.1 ± 2.4 years. This technique was used as a primary procedure in 20 and a revision procedure in 4 patients. Diagnoses included Morquio syndrome (6), spondyloepiphyseal dysplasia (9), spondyloepimetaphyseal dysplasia (5), metatropic dysplasia (3), and Kniest syndrome (1). Ten patients had upper cervical instability and features of cervical myelopathy, and the remaining 14 patients had instability and signal changes on magnetic resonance image. Fusion extended from occiput to C2 in 71% patients, and upper cervical decompression was needed in 92% patients. Postoperatively, all patients were immobilized in a halo vest for mean duration of 12 weeks. Fusion was achieved in all patients. Complications included halo pin-tract infections (7), junctional instability (2), and extension of fusion (4). CONCLUSION: This new cable technique is a good alternative for OCF in patients with SD who have altered anatomy at the craniocervical junction not amenable to rigid internal fixation. LEVEL OF EVIDENCE: 4.

Remote spinal cord injury in mucopolysaccharidosis type IVA after cervical decompression.

Morquio A syndrome (Online Mendelian Inheritance in Man #253000) is a lysosomal storage disease caused by deficiency of N-acetylgalactosamine-6-sulfatase encoded by the GALNS gene. Key clinical features are skeletal dysplasia and short stature.

Unexpected coronary artery findings in mucopolysaccharidosis. Report of four cases and literature review.

INTRODUCTION: The mucopolysaccharidosis syndromes are a group of lethal inherited disorders affecting multiple organ systems by the progressive deposition of glycosaminoglycan. Advances in treatment such as enzyme replacement and hematopoietic stem cell transplantation have significantly improved the outcome of these disorders. An in-depth understanding of the pathophysiology of heart disease in these disorders is essential since death from cardiac causes continues to be common. Epicardial coronary artery luminal narrowing from myointimal proliferation and glycosaminoglycan deposition is well described in severe mucopolysaccharidosis type I [Hurler syndrome, mucopolysaccharide IH] but poorly understood in other "non-Hurler" phenotypes of these disorders. Given the rarity of these conditions, autopsy specimens are uncommon. METHODS: Tissue from epicardial coronary arteries from autopsies of four patients with non-Hurler mucopolysaccharidosis (attenuated type I, type IIIA, type IIIC, and type VI) who had died after hematopoietic cell transplantation (within 1 month in three cases; after 5 years in the fourth) was examined by light microscopy. RESULTS: Unexpectedly, near-normal coronary arteries were observed in the patient with attenuated mucopolysaccharidosis type I, while the coronaries from patients with type IIIA, IIIC, and VI demonstrated classic histologic features of glycosaminoglycan deposition. The most severe findings were found in the MPS IIIC patient who had 5 years of full donor engraftment after transplantation. CONCLUSIONS: Our current understanding of the cardiac manifestations of the mucopolysaccharidoses fails to explain why near-normal coronary arteries may be observed when abnormalities would be most likely to be expected and, conversely, why significant histopathology is present when it would be least expected. Identification of downstream effects of glycosaminoglycan deposition may identify other metabolites or metabolic pathways that are important in the clinicopathologic manifestations of these diseases. SUMMARY: The mucopolysaccharidosis diseases are a group of inherited disorders affecting multiple organ systems by the progressive deposition of glycosaminoglycan. Severe coronary artery disease is well recognized in severe type I mucopolysaccharidosis (Hurler syndrome), but unexpected coronary artery disease occurs in other, "non-Hurler" mucopolysaccharidoses. Factors responsible for the development of coronary pathology in the mucopolysaccharidoses remain elusive.