Consensus-based expert recommendations on the management of MPS IVa and VI in Saudi Arabia.

BACKGROUND: Mucopolysaccharidosis type IVa (Morquio A syndrome) and mucopolysaccharidosis type VI (Maroteaux-Lamy syndrome) are rare inherited lysosomal storage diseases associated with significant functional impairment and a wide spectrum of debilitating clinical manifestations. These conditions are thought to have higher-than-average prevalence rates in Saudi Arabia due to high rates of consanguineous marriage in the country. There are several unmet needs associated with the management of these diseases in Saudi Arabia. MAIN BODY: The aim of this manuscript is to contextualize unmet management needs and provide recommendations to optimize diagnosis, multidisciplinary care delivery, and local data generation in this disease area. An expert panel was assembled comprising seven consultant geneticists from across Saudi Arabia. The Delphi methodology was used to obtain a consensus on statements relating to several aspects of mucopolysaccharidosis types IVa and VI. A consensus was reached for all statements by means of an online, anonymized voting system. The consensus statements pertain to screening and diagnosis, management approaches, including recommendations pertaining to enzyme replacement therapy, and local data generation. CONCLUSION: The consensus statements presented provide specific recommendations to improve diagnostic and treatment approaches, promote multidisciplinary care and data sharing, and optimize the overall management of these rare inherited diseases in Saudi Arabia.

The deleterious variants of N-acetylgalactosamine-6-sulfatase (GalN6S) enzyme trigger Morquio a syndrome by disrupting protein foldings.

Lysosomal enzymes degrade cellular macromolecules, while their inactivation causes human hereditary metabolic disorders. Mucopolysaccharidosis IVA (MPS IVA; Moquio A syndrome) is one of the lysosomal storage disorders caused by a defective Galactosamine-6-sulfatase (GalN6S) enzyme. In several populations, disease incidence is elevated due to missense mutations brought on by non-synonymous allelic variation in the GalN6S enzyme. Here, we studied the effect of non-synonymous single nucleotide polymorphism (nsSNPs) on the structural dynamics of the GalN6S enzyme and its binding with N-acetylgalactosamine (GalNAc) using all-atom molecular dynamics simulation and an essential dynamics approach. Consequently, in this study, we have identified three functionally disruptive mutations in domain-I and domain-II, that is, S80L, R90W, and S162F, which presumably contribute to post-translational modifications. The study delineated that both domains work cooperatively, and alteration in domain II (S80L, R90W) leads to conformational changes in the catalytic site in domain-I, while mutation S162F mainly provokes higher residual flexibility of domain II. These results show that these mutations impair the hydrophobic core, implying that Morquio A syndrome is caused by misfolding of the GalN6S enzyme. The results also show the instability of the GalN6S-GalNAc complex upon substitution. Overall, the structural dynamics resulting from point mutations give the molecular rationale for Moquio A syndrome and, more importantly, the Mucopolysaccharidoses (MPS) family of diseases, re-establishing MPS IVA as a protein-folding disease.Communicated by Ramaswamy H. Sarma.

Bone Growth Induction in Mucopolysaccharidosis IVA Mouse.

Mucopolysaccharidosis IVA (MPS IVA; Morquio A syndrome) is caused by a deficiency of the N-acetylgalactosamine-6-sulfate-sulfatase (GALNS) enzyme, leading to the accumulation of glycosaminoglycans (GAG), keratan sulfate (KS) and chondroitin-6-sulfate (C6S), mainly in cartilage and bone. This lysosomal storage disorder (LSD) is characterized by severe systemic skeletal dysplasia. To this date, none of the treatment options for the MPS IVA patients correct bone pathology. Enzyme replacement therapy with elosulfase alpha provides a limited impact on bone growth and skeletal lesions in MPS IVA patients. To improve bone pathology, we propose a novel gene therapy with a small peptide as a growth-promoting agent for MPS IVA. A small molecule in this peptide family has been found to exert biological actions over the cardiovascular system. This work shows that an AAV vector expressing a C-type natriuretic (CNP) peptide induces bone growth in the MPS IVA mouse model. Histopathological analysis showed the induction of chondrocyte proliferation. CNP peptide also changed the pattern of GAG levels in bone and liver. These results suggest the potential for CNP peptide to be used as a treatment in MPS IVA patients.

Clinical and treatment of 2 children with severe mucopolysaccharidosis type ⅣA from 2 pedigrees and prenatal diagnosis for their sibling / 中华实用儿科临床杂志

Objective:To explore the treatment of the patients with severe phenotype of mucopolysaccharidosis (MPS) type ⅣA by analysing the clinical feature and diagnosis.Methods:Two pediatric patients diagnosed as MPS ⅣA in severe form were enrolled in Children′s Hospital Affiliated to Zhengzhou University from August 2021 to April 2022.Two children from 2 pedigrees with the main manifestations of short stature and bone deformities were retrospectively included.The clinical manifestations, biochemical indexes, and bone imaging findings were retrospectively analyzed.Peripheral blood leukocytes were collected and subjected to the N-acetylgalactosamine-6-sulfatase (GALNS) assay and genetic sequencing.Gene analysis of amniotic fluid cells at the 18 th week of the second pregnancy of the mother of case 2 was performed for prenatal diagnosis.Allogeneic hematopoietic stem cell transplantation (allo-HSCT) was performed in both patients and to explore the treatment of patients with MPS ⅣA. Results:Both cases presented clinical manifestations of short stature, joint laxity, pectus carinatum, and genu valgus.X-ray examination revealed the decreased bone mineral density, ulnar deviation of the radial epiphysis, kyphosis and scoliosis.The respiratory and skeletal systems were affected in both patients, and the optic nerve was suspiciously affected. GALNS gene analysis showed that there were 2 missense mutations of c. 1019G>A (p.G340D) and c. 706C>G (p.H236D) in case 1, and 2 missense mutations of c. 425A>G (p.H142R) and c. 463G>A (p.G155R) were detected in case 2.Mutations in both cases were inherited from their fathers and mothers, which were all newly discovered that have not been reported.Only the c. 463G>A mutation was detected in the amniotic fluid cells of the mother of case 2.It is confirmed that case 2 was the carrier of MPS ⅣA, whose gene mutation was from the mother, and case 2 did not suffer the same disease as the proband.Both cases were treated with allo-HSCT with full donor chimerism and no severe transplant complications were reported.Their GALNS activity was within the normal range, and the scores of activities of daily living were higher than those before transplantation. Conclusions:The MPS ⅣA patients with severe phenotype is a rare autosomal recessive disease caused by GALNS mutations that is difficult to diagnose and poor prognosis.Early detection, diagnosis, and effective treatment contribute to improve the long-term quality of life.The allo-HSCT is an effective therapeutic strategy for MPS ⅣA.

Characterization of a novel exonic deletion in the GALNS gene causing Morquio A syndrome.

Mucopolysaccharidosis IVA or Morquio A syndrome is a rare lysosomal storage disorder caused by N-acetylgalactosamine-6-sulfatase deficiency. A diagnosis can be provided by the identification of reduced N-acetylgalactosamine-6-sulfatase activity as well as detection of compound heterozygous or homozygous pathogenic variants in GALNS. We present a case of two sisters of healthy non-consanguineous parents with a severe classical phenotype of Morquio A syndrome. Both patients were found to carry a novel homozygous deletion of exon 9, which was initially suspected by next generation sequencing (NGS) due to lack of coverage, but could not be confirmed by this methodology. Therefore, an allele specific polymerase chain reaction assay was designed to confirm the exon 9 deletion and determine the precise deletion breakpoints (c.899-397_1003-1862del) for our patients. Recognizing limitations of molecular testing is important to ensure proper diagnosis and subsequent treatment for individuals with Morquio A syndrome.

Findings from the Morquio A Registry Study (MARS) after 6 years: Long-term outcomes of MPS IVA patients treated with elosulfase alfa.

BACKGROUND: The Morquio A Registry Study (MARS) is an ongoing, multinational, observational study of patients with MPS IVA. Key objectives of MARS are to characterize the heterogeneity and natural history of disease and to evaluate long-term effectiveness and safety of elosulfase alfa enzyme replacement therapy (ERT). Enrollment began in September 2014; data on medical history, clinical outcomes, and safety assessments are collected as part of routine care. RESULTS: As of February 2021, 381 subjects from 17 countries had enrolled in MARS: 58 ERT-naïve subjects and 323 ERT-treated subjects (≥1 infusion), with a mean ERT exposure of 5.5 years (SD 2.8) and median age at first ERT treatment of 9.8 years. ERT-treated subjects were younger at diagnosis (median 3.4 vs 6.5 years) relative to ERT-naïve subjects. Among ERT-treated subjects, urinary keratan sulfate (uKS) levels declined from pre-ERT baseline to last follow-up on treatment (mean % change [95% confidence interval]: -52.5% [-57.5%, -47.4%]; n = 115) and 6-min walk test distance remained stable (mean change: -6.1 [-27.6, 15.5] m; n = 131) over a mean follow-up of 5.5 years. Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) increased in subjects who were < 18 years of age at ERT initiation (mean change: +0.3 [0.1, 0.4] L and + 0.4 [0.3, 0.5] L; mean follow-up: ∼6 years; n = 82) and were stable in subjects ≥18 years (mean change: 0.0 [-0.0, 0.1] L and 0.0 [-0.1, 0.1] L; mean follow-up: 4.6 years; n = 38). Overall, 148 (47.1%) ERT-treated subjects experienced ≥1 adverse event (AE) and 110 subjects (35%) reported ≥1 serious AE. Drug-related AEs were reported in 39 (12.4%) subjects; the most common were hypersensitivity (9 subjects [2.9%]), urticaria (8 subjects [2.5%]), and pyrexia (7 subjects [2.2%]). CONCLUSIONS: MARS is the longest and largest observational study of MPS IVA patients to date, with a heterogenous population that is representative of the MPS IVA population overall. Data collected over the first 6 years of MARS provide real-world evidence for long-term stabilization of endurance and respiratory function among ERT-treated patients, with no new safety concerns identified.

Case Report: Diagnosis of Mucopolysaccharidosis Type IVA With Compound Heterozygous Galactosamine-6 Sulfatase Variants and Biopsy of Replaced Femoral Heads.

Introduction: Mucopolysaccharidosis Type IVA (MPS IVA) or Morquio A Syndrome, is a rare metabolic disorder caused by compromised galactosamine-6 sulfatase (GALNS) encoded by GALNS gene (NM_000512.5), leading to keratin sulfate (KS), and chondroitin-6-sulfate accumulation in various organs. We present a 17-year-old woman with progressive bilateral hip pain and radiographic evidence of spondyloepiphyseal dysplasia. Methods: Diagnosis of MPS IVA was made based on whole-exome sequencing (WES) of blood samples collected from the patient and family members, high urinary glycosaminoglycan excretion, supportive clinical manifestations, radiographic examinations, including whole-body X-rays, cervical MRI, and pelvic CT. The patient underwent bilateral total hip arthroplasties sequentially, at a 1-month interval. Femoral heads were preserved for the micro-CT (µCT) analysis and the osteochondral histology examination. Results: The patient presented with multiple skeletal deformities, including vertebras and long bone deformities. WES disclosed compound heterozygous variants at exon 11 (c.1156C>T) and exon 12 (c.1288C>G) of the GALNS (NM_000512.5). The µCT analysis revealed significant bone quantity loss and microarchitectural change in both weight-bearing area (WBA) and non-weight-bearing area (NWBA) of the femoral heads, while histological analysis showed structural abnormity of articular cartilage in the WBA of the femoral heads. Conclusion: We have found compound heterozygous variants of GALNS. This is also the first study to report the microarchitectural and histological changes of both subchondral bone and articular cartilage of the femoral head in a patient with MPS IVA.

Clinical characteristics and effects of enzyme replacement therapy with elosulfase alfa in Korean patients with mucopolysaccharidosis type IVA.

Mucopolysaccharidosis type IVA (MPS IVA) is a rare autosomal recessive disorder caused by a deficiency in N-acetylgalactosamine-6-sulfatase, which results in skeletal and connective tissue abnormalities, as well as various non-skeletal manifestations. Although enzyme replacement therapy (ERT) is recommended as the first-line treatment, the outcomes of ERT on bone pathology remain controversial. We report clinical characteristics and outcomes of ERT in 9 patients with MPS IVA (6 males and 3 females) from 7 unrelated families. During ERT, results from pulmonary function tests, echocardiography, the 6-min walk test, and the Functional Independence Measure were monitored biannually. Anthropometric data were compared with previously reported growth charts of subjects with MPS IVA. Among the 9 patients (5 severe, and 4 slowly progressive form), 7 patients (5 severe, 2 slowly progressive) commenced ERT at a median age of 3.8 years (range: 0.8-13.7 years) and were treated for a median duration of 1.9 years (range: 1.2-5.7 years). Mean height standard deviation scores using MPS IVA growth charts were + 0.4 (+0.0 in severe phenotypes) at initiation and + 0.7 (+0.2 in severe phenotypes) at the last follow-up. Four patients with severe phenotypes underwent surgery for cervical myelopathy and 1 patient with a slowly progressive phenotype underwent a bilateral pelvic osteotomy for hip pain during ERT. The parameters of pulmonary and heart function, endurance, and Functional Independence Measure scores were maintained or increased after ERT. Overall, ERT was well tolerated without deterioration of cardiorespiratory and functional outcomes during treatment, although skeletal outcomes, including growth, were limited.

The GALNS p.P77R variant is a probable Gujarati-Indian founder mutation causing Mucopolysaccharidosis IVA syndrome.

BACKGROUND: Mucopolysaccharidosis IVA (Morquio syndrome A, MPS IVA) is an autosomal recessive lysosomal storage disorder caused due to biallelic variants in the N-acetylgalactoseamine-6-sulfate sulfatase (GALNS) gene. The mutation spectrum in this condition is determined amongst sub-populations belonging to the north, south and east India geography, however, sub-populations of west Indian origin, especially Gujarati-Indians, are yet to be studied. We aimed to analyse the variants present in the GLANS gene amongst the population of Gujarat by sequencing all exons and exon-intron boundaries of the GALNS gene in patients from 23 unrelated families. RESULTS: We report 11 variants that include eight missense variants: (p.L36R, p.D39G, p.P77R, p.C79R, pP125L, p.P151L, p.G255A and p.L350P), one splice site variant: (c.121-7C > G), one small insertion: (c.1241_1242insA, p.I416HfsTer2) and one small deletion: (c.839_841delACA). Of these, three missense variants (p.D39G, p.G255A and p.L350P), one splice site and the two indels mentioned above are novel. Interestingly, we observed a higher than anticipated prevalence of p.P77R variant in our cohort (n = 14/25, 56%). Haplotype analysis in cases with p.P77R variant and 63 ethnicity matched healthy population controls suggested a 4 SNP haplotype block present in cases compared to controls (likelihood ratio test p-value = 1.16 × 10-13), thereby suggesting p.P77R variant as a founder variant in the Gujarati-Indian population. Furthermore, age of mutation analysis suggested the variant to have arisen approximately 450 years ago in the population. CONCLUSION: p.P77R variant in the GLANS gene is likely to be a founder variant in MPS IVA patients of Gujarati-Indian ancestry and appeared approximately 450 years ago in the population. To our knowledge, this is the first variant to be posited as a founder variant in the GLANS gene in patients with MPS IVA syndrome.

The landscape of Mucopolysaccharidosis in Southern and Eastern European countries: a survey from 19 specialistic centers.

BACKGROUND: Mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders caused by defects in genes coding for different lysosomal enzymes which degrade glycosaminoglycans. Impaired lysosomal degradation causes cell dysfunction leading to progressive multiorgan involvement, disabling consequences and poor life expectancy. Enzyme replacement therapy (ERT) is now available for most MPS types, offering beneficial effects on disease progression and improving quality of life of patients. The landscape of MPS in Europe is not completely described and studies on availability of treatment show that ERT is not adequately implemented, particularly in Southern and Eastern Europe. In this study we performed a survey analysis in main specialist centers in Southern and Eastern European countries, to outline the picture of disease management in the region and understand ERT implementation. Since the considerable number of MPS IVA patients in the region, particularly adults, the study mainly focused on MPS IVA management and treatment. RESULTS: 19 experts from 14 Southern and Eastern European countries in total responded to the survey. Results outlined a picture of MPS management in the region, with a high number of MPS patients managed in the centers and a high level of care. MPS II was the most prevalent followed by MPS IVA, with a particular high number of adult patients. The study particularly focused on management and treatment of MPS IVA patients. Adherence to current European Guidelines for follow-up of MPS IVA patients is generally adequate, although some important assessments are reported as difficult due to the lack of MPS skilled specialists. Availability of ERT in Southern and Eastern European countries is generally in line with other European regions, even though regulatory, organizational and reimbursement constrains are demanding. CONCLUSIONS: The landscape of MPS in Southern and Eastern European countries is generally comparable to that of other European regions, regarding epidemiology, treatment accessibility and follow up difficulties. However, issues limiting ERT availability and reimbursement should be simplified, to start treatment as early as possible and make it available for more patients. Besides, educational programs dedicated to specialists should be implemented, particularly for pediatricians, clinical geneticists, surgeons, anesthesiologists and neurologists.

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.

Clinical features and health-related quality of life in adult patients with mucopolysaccharidosis IVA: the Spanish experience.

BACKGROUND: Mucopolysaccharidosis (MPS) IVA or Morquio A syndrome is a progressive and disabling disease characterized by a deficiency of the enzyme N-acetylgalactosamine-6-sulphate sulphatase. Its clinical presentation is very heterogeneous and poorly understood in adults. The aim of this study was to describe the clinical manifestations of MPS IVA in adult patients in Spain and to assess their health-related quality of life (HRQoL). RESULTS: Thirty-three patients from nine reference centres participated in the study. The median age was 32 (interquartile range [IQR]: 20.5-40.5) years. The phenotype was classical in 54.5% of patients, intermediate in 33.3% of patients, and non-classical in 12.1% of patients. The most common clinical manifestation was bone dysplasia, with a median height of 118 (IQR: 106-136) cm. Other frequent clinical manifestations were hearing loss (75.7%), ligamentous laxity (72.7%), odontoid dysplasia (69.7%), limb deformities that required orthopaedic aids (mainly hip dysplasia and genu valgus) (63.6%), and corneal clouding (60.6%). In addition, 36.0% of patients had obstructive sleep apnoea/hypopnoea syndrome and 33.3% needed non-invasive ventilation. Cervical surgery and varisation osteotomy were the most common surgical interventions (36.4% each). Almost 80% of patients had mobility problems and 36.4% used a wheelchair at all times. Furthermore, 87.9% needed help with self-care, 33.3% were fully dependent, and 78.8% had some degree of pain. HRQoL according to the health assessment questionnaire was 1.43 (IQR: 1.03-2.00) in patients with the non-classical phenotype, but 2.5 (IQR: 1.68-3.00) in those with the classical phenotype. Seven patients were initiated on enzyme replacement therapy (ERT), but two of them were lost to follow-up. Lung function improved in four patients and slightly worsened in one patient. The distance achieved in the six-minute walk test increased in the four patients who could perform it. HRQoL was better in patients treated with elosulfase alfa, with a median (IQR) of 1.75 (1.25-2.34) versus 2.25 (1.62-3.00) in patients not treated with ERT. CONCLUSIONS: The study provides real-world data on patients with MPS IVA. Limited mobility, difficulties with self-care, dependence, and pain were common, together with poor HRQoL. The severity and heterogeneity of clinical manifestations require the combined efforts of multidisciplinary teams.

The youngest pair of siblings with Mucopolysaccharidosis type IVA to receive enzyme replacement therapy to date: A case report.

Mucopolysaccharidosis type IVA (OMIM 253000) is an autosomal recessive disorder caused by defective activity of the N-acetylgalactosamine 6-sulfatase (GALNS) enzyme. In 2014, enzyme replacement therapy (ERT) using recombinant human GALNS became available for affected patients. There is a limited number of studies to date that have explored the effect of ERT in infancy and there is also a lack of data assessing the effect of ERT in systems other than the skeletal. Here, we report on the effect of ERT in the youngest pair of siblings treated to date: Patient A, currently 4 years old, who started treatment at the age of 5 months; and Patient B, currently 3 years old, who started treatment at 58 days of life. Moreover, we investigate the effect of early ERT on the cardiovascular system. Our results show that, even when ERT is started before 2 months of age, it cannot fully prevent disease progression. As for the effect of ERT on the cardiovascular system, our preliminary results suggest that early treatment might play a role in preserving a normal left ventricular mass index in affected patients at least up to 1 year, but further observation over time will be required. Overall, this report shows that early diagnosis remains crucial and that prompt initiation of ERT has limited effect in slowing progression of the skeletal phenotype, thus confirming the need for new therapeutic approaches that target the skeletal system in affected patients.

Molecular basis of mucopolysaccharidosis IVA (Morquio A syndrome): A review and classification of GALNS gene variants and reporting of 68 novel variants.

Mucopolysaccharidosis IVA (MPS IVA, Morquio A syndrome) is a rare autosomal recessive lysosomal storage disorder caused by mutations in the N-acetylgalactosamine-6-sulfatase (GALNS) gene. We collected, analyzed, and uniformly summarized all published GALNS gene variants, thus updating the previous mutation review (published in 2014). In addition, new variants were communicated by seven reference laboratories in Europe, the Middle East, Latin America, Asia, and the United States. All data were analyzed to determine common alleles, geographic distribution, level of homozygosity, and genotype-phenotype correlation. Moreover, variants were classified according to their pathogenicity as suggested by ACMG. Including those previously published, we assembled 446 unique variants, among which 68 were novel, from 1190 subjects (including newborn screening positive subjects). Variants' distribution was missense (65.0%), followed by nonsense (8.1%), splicing (7.2%), small frameshift deletions(del)/insertions(ins) (7.0%), intronic (4.0%), and large del/ins and complex rearrangements (3.8%). Half (50.4%) of the subjects were homozygous, 37.1% were compound heterozygous, and 10.7% had only one variant detected. The novel variants underwent in silico analysis to evaluate their pathogenicity. All variants were submitted to ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/) to make them publicly available. Mutation updates are essential for the correct molecular diagnoses, genetic counseling, prenatal and preimplantation diagnosis, and disease management.

Demographic, clinical, and ancestry characterization of a large cluster of mucopolysaccharidosis IV A in the Brazilian Northeast region.

Mucopolysaccharidosis (MPS) IVA is a rare autosomal recessive disease with a highly variable distribution worldwide. Discrepancies in the incidence of MPS IVA among populations of different ethnicities are mostly attributed to founder effects. Demographic and clinical data from 28 MPS IVA patients, followed at a single center, and ancestry (Y chromosome and mitochondrial markers) of a subsample of 17 patients, most with the p.Ser341Arg (c.1023C>G) mutation were analyzed. Parental consanguinity was observed in 15/20 couples; a rare homozygous N-acetylgalactosamine-6-sulfatase (GALNS) mutation was found in 7/16 families with intra-familial phenotypic heterogeneity. Paternal ancestry was 94.2% (16/17) European, 5.8% (1/17) African, and 0% Amerindian. The European paternal haplogroups R1a, R1b, and R* accounted for 94.2% (16/17) of the patients. The R1b haplogroup, identified in 59% (10/17) of the patients, is frequently found in populations from the Iberian Peninsula. European, Amerindian, and African maternal ancestry was observed in 46.9% (8/17), 35.4% (6/17), and 17.7% (3/17) of the patients, respectively. Study of a cluster of MPS IVA patients from Northeastern Brazil, with high parental consanguinity and phenotypic heterogeneity showed predominantly European parental ancestry. This ancestry finding corroborates historical data on the local settlement, formed predominantly by European men.

Morquio A syndrome and effect of enzyme replacement therapy in different age groups of Turkish patients: a case series.

BACKGROUND: This case series includes longitudinal clinical data of ten patients with Morquio A syndrome from south and southeastern parts of Turkey, which were retrospectively collected from medical records. All patients received enzyme replacement therapy (ERT). Clinical data collected included physical appearance, anthropometric data, neurological and psychological examinations, cardiovascular evaluation, pulmonary function tests, eye and ear-nose-throat examinations, endurance in the 6-min walk test and/or 3-min stair climb test, joint range of motion, and skeletal investigations (X-rays, bone mineral density). RESULTS: At the time of ERT initiation, two patients were infants (1.8 and 2.1 years), five were children (3.4-7.1 years), and three were adults (16.5-39.5 years). Patients had up to 4 years follow-up. Most patients had classical Morquio A, based on genotypic and phenotypic data. Endurance was considerably reduced in all patients, but remained relatively stable or increased over time in most cases after treatment initiation. Length/height fell below normal growth curves, except in the two infants who started ERT at ≤ 2.1 years of age. All patients had skeletal and/or joint abnormalities when ERT was started. Follow-up data did not suggest improvements in skeletal abnormalities, except in one of the younger infants. Nine patients had corneal clouding, which resolved after treatment initiation in the two infants, but not in the other patients. Hepatomegaly was reported in seven patients and resolved with treatment in five of them. Other frequent findings at treatment initiation were coarse facial features (N = 9), hearing loss (N = 6), and cardiac abnormalities (N = 6). Cardiac disease deteriorated over time in three patients, but did not progress in the others. CONCLUSIONS: Overall, this case series with Morquio A patients confirms clinical trial data showing long-term stabilization of endurance after treatment initiation across ages and suggest that very early initiation of ERT optimizes growth outcomes.

Clinical outcomes in elderly patients with Morquio a syndrome receiving enzyme replacement therapy - experience in a Colombian center.

INTRODUCTION: Mucopolysaccharidosis type IV A (MPS IVA) or Morquio A syndrome is an autosomal recessive lysosomal storage disease caused by GALNS gene mutations that lead to a deficiency of the N-acetylgalactosamine-6-sulfate sulfatase enzyme and the accumulation of two glycosaminoglycans in cell lysosomes, namely, chondroitin and keratan sulfate. OBJECTIVE: To present two female patients with Morquio A syndrome in their late adult years (over 50 years of age) with a classical phenotype, treated with enzyme replacement therapy; and to present a summary of the natural history and the characteristics of the disease, and the benefit of comprehensive management. MATERIALS AND METHODS: Descriptive clinical study before and after the treatment with enzyme replacement therapy as part of the comprehensive management of MPS IVA. RESULTS: Enzyme replacement therapy with elosulfase alfa was effective, with an adequate safety profile in these two patients, showing evidence of sustained improvement in terms of endurance and gait patterns. CONCLUSION: We present two cases of MPS IVA, with longer survival than reported previously in classical phenotypes associated with this disease condition. There is a paucity of reports of similar cases in the literature. We believe that the clinical heterogeneity of the disease manifesting with the classical phenotype, together with comprehensive management, have played a role in the survival of these two patients. Therapy with elosulfase alfa as part of comprehensive management has been crucial; we suspect a clinical response and infer a better quality of life and reduced burden for the caregiver, supporting its use in older patients.

Natural history of the oldest known females with mucopolysaccharidosis type IVA (Morquio A syndrome).

Mucopolysaccharidosis Type IVA (MPS IVA), also known as Morquio A syndrome, is an autosomal recessive lysosomal storage disorder that results from variants in the GALNS gene that encodes the enzyme galactosamine-6-sulfate sulfatase. This syndrome has systemic manifestations including, but not limited to, musculoskeletal, respiratory, cardiovascular, rheumatologic, neurologic, dental, ophthalmologic, and otologic. This condition is usually detected within the first few years of life with an average life expectancy of 25.3 ± 17.43 years. We report the natural history of two of the oldest known females with MPS IVA, who were each clinically diagnosed at 4 years of age and who are now 74 and 70 years of age, respectively. They are both affected by pathogenic variants c.319G>A (p.Ala107Thr) and c.824 T>C (p.Leu275Pro) in the GALNS gene.

A Case Report of a Japanese Boy with Morquio A Syndrome: Effects of Enzyme Replacement Therapy Initiated at the Age of 24 Months.

BACKGROUND: Morquio A syndrome, mucopolysaccharidosis type IVA (MPS IVA), is a lysosomal storage disorder caused by the deficient activity of N-acetylgalactosamine-6-sulfatase (GalNac6S), due to alterations in the GALNS gene. This disorder results in marked abnormalities in bones and connective tissues, and affects multiple organs. Here, we describe the clinical course of a Japanese boy with MPS IVA who began enzyme replacement therapy (ERT) at the age of 24 months. PATIENT: the patient presented for kyphosis treatment at 22 months of age. An X-ray examination revealed dysostosis multiplex. Uronic acids were elevated in the urine and the keratan sulfate (KS) fraction was predominant. The leukocyte GalNac6S enzyme activity was extremely low. The patient exhibited the c.463G > A (p.Gly155Arg) mutation in GALNS. Based on these findings, his disease was diagnosed as classical (severe) Morquio A syndrome. An elosulfase alfa infusion was initiated at the age of 24 months. The patient's body height improved from -2.5 standard deviation (SD) to -2 SD and his physical activity increased during the first 9 months on ERT. However, he gradually developed paralysis in the lower legs with declining growth velocity, which required cervical decompression surgery in the second year of the ERT. The mild mitral regurgitation, serous otitis media, and mild hearing loss did not progress during treatment. CONCLUSION: early initiation of the elosulfase alfa to our patient showed good effects on the visceral system and muscle strength, while its effect on bones appeared limited. Careful observation is necessary to ensure timely surgical intervention for skeletal disorders associated with neurological symptoms. Centralized and multidisciplinary management is essential to improve the prognosis of pediatric patients with MPS IVA.

Modeling Morquio A Syndrome: An Anthropometric Study of Body Characteristics and Stature.

BACKGROUND: Morquio A syndrome or mucopolysaccharidosis (MPS) IVA is an autosomal recessive, life-limiting lysosomal storage disease caused by deficient activity of the enzyme galactosamine-6-sulfatase. Common early symptoms such as abnormalities of body stature can facilitate timely diagnosis. This study aimed to create a pattern of face and body stature based on anthropometric measurements taken from a cohort of Polish patients with MPS IVA. METHODS: Analysis of 11 somatometric and 14 craniofacial features was performed on 20 patients with MPS IVA, aged from 3 months to 26 years. The diagnosis of MPS IVA was confirmed by enzymatic and molecular analysis. Two-tailed t-tests were used to compare mean values for body length and weight at birth between the MPS IVA patients and the general population. To show the degree and direction of deviation z-scores were calculated and then used to construct a model of an average MPS IVA patient. RESULTS: Mean values for body height and weight at birth were greater for boys than for the general population. The observed pattern of head and body shape indicated that dwarfism occurred with age as a result of the relatively short trunk and lower limbs. Skeletal abnormalities included a bell-shaped chest with the ratio of chest depth to chest width being significantly above the norm. The head and neck were relatively elongated, in comparison to body height, and tucked between narrow shoulders. The head had dolichocephalic shape, while the nose was short with wide nostrils. CONCLUSIONS: Multiple anthropometric measurements, including age ranges, allowed for the creation of a model that showed the most characteristic features of the MPS IVA phenotype.