The use of recombinant human growth hormone in patients with Mucopolysaccharidoses and growth hormone deficiency: a case series

Behavioural disorders and sleep problems in Sanfilippo syndrome: overlaps with some other conditions and importance indications

Sanfilippo syndrome (MPS III) is one of the types of mucopolysaccharidoses (MPS), a group of inherited metabolic diseases in which the accumulation of glycosaminoglycans (GAGs) results from deficiency of different lysosomal enzymes. The hallmarks of MPS III are relatively minor somatic abnormalities with severe and progressive central nervous system (CNS) symptoms. An analysis of the literature showed that the biggest problems for carers of people with MPS III are behavioural disorders and sleep disorders. Despite extensive discussions on improving the quality of life of patients, little attention was paid to the families/carers of patients. The families/carers are providing appropriate medical and palliative care to the patient every day due to their loss of mobility, self-care skills, tube feeding, airway clearance and other supports continue to have an adverse effect on the quality of life of families/carers. However, a literature review of possible solutions showed that effective methods (both pharmacological and non-pharmacological) exist. The needs of carers of MPS III patients should receive as much attention as the search for new treatments. There are many options for dealing with such problems. The key issue is to identify the source of the problem and choose the most effective therapy. Alleviating behavioural disorders, pain complaints and sleep problems will have a positive impact not only on the quality of life of carers/families, but also on the patients themselves.

MPSI Manifestations and Treatment Outcome: Skeletal Focus

Mucopolysaccharidosis type I (MPSI) (OMIM #252800) is an autosomal recessive disorder caused by pathogenic variants in the IDUA gene encoding for the lysosomal alpha-L-iduronidase enzyme. The deficiency of this enzyme causes systemic accumulation of glycosaminoglycans (GAGs). Although disease manifestations are typically not apparent at birth, they can present early in life, are progressive, and include a wide spectrum of phenotypic findings. Among these, the storage of GAGs within the lysosomes disrupts cell function and metabolism in the cartilage, thus impairing normal bone development and ossification. Skeletal manifestations of MPSI are often refractory to treatment and severely affect patients’ quality of life. This review discusses the pathological and molecular processes leading to impaired endochondral ossification in MPSI patients and the limitations of current therapeutic approaches. Understanding the underlying mechanisms responsible for the skeletal phenotype in MPSI patients is crucial, as it could lead to the development of new therapeutic strategies targeting the skeletal abnormalities of MPSI in the early stages of the disease.

Effect of Vitamin D Combined with Recombinant Human Growth Hormone in Children with Growth Hormone Deficiency

Objective

Growth hormone deficiency (GHD) refers to the complete or partial lack of pituitary growth hormone synthesis and secretion. This study is aimed at investigating the efficacy of vitamin D and recombinant human growth hormone (rhGH) in children with GHD.

Methods

A total of 100 children with GHD at our hospital were included between 1^st January 2018 and 31^st October 2020. The patients were divided into a study group (n = 70, received vitamin D combined with rhGH) and a control group (n = 30, received rhGH). The growth and development (bone age, growth rate, and height), bone metabolism (bone alkaline phosphatase (BAP), β-collagen degradation product (β-CTX), osteocalcin (OC), and amino-terminal propeptide type I procollagen (PINP)), insulin-like growth factor 1 (IGF-1), ghrelin, and adverse reactions in the two groups were measured before and 12 months after treatment.

Results

There were no significant differences in the bone age, growth rate, and height between the two groups before treatment. After 12 months of treatment, the bone age, growth rate, and height of the study group were significantly higher than those of the control group. After 12 months of treatment, the levels of serum BAP, PINP, and OC in the study group were significantly higher than those in the control group, while the levels of β-CTX in the study group were significantly lower than those in the control group. The serum IGF-1 level in the study group was significantly higher than that in the control group, while the ghrelin level in the study group was lower. There was no significant difference in the incidence of adverse reactions between the two groups.

Conclusion

Combined rhGH and vitamin D treatment can promote growth and development, improve bone metabolism, and regulate IGF-1 and ghrelin levels.

Predictors of growth patterns in children with mucopolysaccharidosis I after haematopoietic stem cell transplantation

Mucopolysaccharidosis type I (MPS I) is an autosomal-recessive metabolic disorder caused by an enzyme deficiency of lysosomal alpha-l-iduronidase (IDUA). Haematopoietic stem cell transplantation (HSCT) is the therapeutic option of choice in MPS I patients younger than 2.5 years, which has a positive impact on neurocognitive development. However, impaired growth remains a problem. In this monocentric study, 14 patients with MPS I (mean age 1.72 years, range 0.81-3.08) were monitored according to a standardised follow-up program after successful allogeneic HSCT. A detailed anthropometric program was carried out to identify growth patterns and to determine predictors of growth in these children. All patients are alive and in outpatient care (mean follow-up 8.1 years, range 0.1-16.0). Progressively lower standard deviation scores (SDS) were observed for body length (mean SDS -1.61; -4.58 - 3.29), weight (-0.56; -3.19 - 2.95), sitting height (-3.28; -7.37 - 0.26), leg length (-1.64; -3.88 - 1.49) and head circumference (0.91; -2.52 - 6.09). Already at the age of 24 months, significant disproportions were detected being associated with increasing deterioration in growth for age. Younger age at HSCT, lower counts for haemoglobin and platelets, lower potassium, higher donor-derived chimerism, higher counts for leukocytes and recruitment of a matched unrelated donor (MUD) positively correlated with body length (p ≤ 0.05). In conclusion, this study characterised predictors and aspects of growth patterns in children with MPS I after HSCT, underlining that early HSCT of MUD is essential for slowing body disproportion.

A Case of Growth Hormone Use in Dyggve–Melchior–Clausen Syndrome

Short stature has many causes including genetic disease, skeletal dysplasias, endocrinopathies, familial short stature, and nutritional deficiencies. Recombinant growth hormone (rGH) therapy may be employed to improve stature based on the underlying etiology and growth velocity. Skeletal dysplasia in Dyggve–Melchior–Clausen (DMC) syndrome tends to be progressive, typically with hip involvement, and ultimately leads to bilateral dislocation of the hip joints. Here, we present a pediatric patient with short stature treated with rGH therapy, complicated by the development of debilitating, bilateral hip pain, and found to have DMC syndrome. Our patient had limited range of motion at several joints including the hips after receiving 6 months of rGH therapy. Given the timing of the patient's rGH therapy and the progression of her disease, it is difficult to determine if there were any benefits and instead, is concerning for worsening of her skeletal dysplasia with rGH therapy use. Consequently, patients with severe short stature should have a thorough workup for genetic causes like DMC syndrome, before initiating rGH therapy to determine any potential benefits or harms of treatment.

A 9-Month-Old with Skeletal Abnormalities and a Consanguineous Sibling with Mucopolysaccharidosis IVA: The Role of Urinary Glycosaminoglycan Testing in Disease Diagnosis and Treatment Monitoring

Mucopolysaccharidosis IVA (MPS IVA) is a rare autosomal recessive lysosomal storage disorder resulting from N-acetylgalactosamine-6-sulfatase (GALNS) deficiency that occurs in approximately 1 in 76 000 to 1 in 640 000 live births. Given that the diagnosis of MPS IVA relies heavily on the results of initial urine glycosaminoglycan (GAG) screening, cases that present with falsely normal urine GAG concentrations can delay the diagnosis and follow-up care for patients. This case study follows a patient diagnosed with MPS IVA at 9 months of age based on relation to a consanguineous 3-year-old sibling with MPS IVA and the use of direct enzyme activity analysis. Details regarding skeletal presentation and identification of genetic variants are presented along with data on follow-up urinary GAG monitoring during treatment with enzyme replacement therapy and treatment for a growth hormone disorder.

Failures of Endochondral Ossification in the Mucopolysaccharidoses

PURPOSE OF REVIEW

The mucopolysaccharidoses (MPS) are a group of inherited lysosomal storage disorders characterized by abnormal accumulation of glycosaminoglycans (GAGs) in cells and tissues. MPS patients frequently exhibit failures of endochondral ossification during postnatal growth leading to skeletal deformity and short stature. In this review, we outline the current understanding of the cellular and molecular mechanisms underlying failures of endochondral ossification in MPS and discuss associated treatment challenges and opportunities.

RECENT FINDINGS

Studies in MPS patients and animal models have demonstrated that skeletal cells and tissues exhibit significantly elevated GAG storage from early in postnatal life and that this is associated with impaired cartilage-to-bone conversion in primary and secondary ossification centers, and growth plate dysfunction. Recent studies have begun to elucidate the underlying cellular and molecular mechanisms, including impaired chondrocyte proliferation and hypertrophy, diminished growth factor signaling, disrupted cell cycle progression, impaired autophagy, and increased cell stress and apoptosis. Current treatments such as hematopoietic stem cell transplantation and enzyme replacement therapy fail to normalize endochondral ossification in MPS. Emerging treatments including gene therapy and small molecule-based approaches hold significant promise in this regard. Failures of endochondral ossification contribute to skeletal deformity and short stature in MPS patients, increasing mortality and reducing quality of life. Early intervention is crucial for effective treatment, and there is a critical need for new approaches that normalize endochondral ossification by directly targeting affected cells and signaling pathways.

Best practices, challenges and innovations in pediatrics in 2019

This paper runs through key progresses in epidemiology, pathomechanisms and therapy of various diseases in children that were issued in the Italian Journal of Pediatrics at the end of last year. Novel research and documents that explore areas such as allergy, critical care, endocrinology, gastroenterology, infectious diseases, neonatology, neurology, nutrition, and respiratory tract illnesses in children have been reported. These observations will help to control childhood illnesses.

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.