Use of Growth Hormone Treatment in Skeletal Dysplasia - A Review.

Most patients with skeletal dysplasia show severe short stature. Surgical therapy has been attempted to correct bone deformities, but therapy for improving their severe short stature has been rarely attempted. We undertook a clinical trial of growth hormone (GH) therapy for patients with skeletal dysplasia accompanying severe short stature caused by achondroplasia (ACH), hypochondroplasia (HCH), pseudoachondroplasia (PSACH), spondyloepiphyseal dysplasia congenita (SED), or Schmid type metaphyseal dysplasia (MD). This study examined the efficacy of GH therapy on height increase and change of height SD score over a 1-year period in patients with skeletal dysplasia and showed a short-term efficacy for skeletal dysplasia. In ACH, HCH, and MD, GH had a significant effect on height gain. However, PSACH and SED showed no height gain efficacy; in cases of PSACH, height SD score was worse after therapy. Severe adverse events were not observed except in one SED case, in which scoliosis worsened and height did not increase. For patients with skeletal dysplasia, GH therapy is moderately effective for height gain. It is ineffective in cases with severe spinal deformities, however; although bone growth was promoted, the ligaments and matrix were too weak to support muscle tonus and the effects of gravity, resulting in worsened kyphosis and lordosis. These results clarify why GH therapy is ineffective for height gain. The pathogenic genes of skeletal dysplasia have recently been detected and consequently changes in bone formation have been investigated in detail. Careful consideration of indications for therapy and cautious observation during therapy are crucial when attempting to treat advanced bone deformities.

Longitudinal growth of bone depends on the proliferation and differentiation of chondrocytes located in growth plate. Recent advances in understanding the process of chondrocyte proliferation and differentiation reveal the local and systemic factors responsible for the process. SOX9, Ihh and FGFR3 are the former, growth hormone and thyroid hormone the latter. Achondroplasia, a representative entity of skeletal dysplasia is caused by the abnormality of FGFR3 and exhibits short stature. Hypofunction of growth hormone and thyroid hormone are associated with short stature as well.

Background. The identification of a missense mutation (G380R) in the fibroblast growth factor receptor 3 (FGFR3) gene in patients with achondroplasia was followed by the detection of common FGFR3 mutations in two clinically related occurrences of skeletal dysplasia.: hypochondroplasia, and thanatophoric dysplasia. In this study, we investigated the FGFR3 mutation of achondroplasia, hypochondroplasia, and thanatophoric dysplasia in Taiwanese patients. Methods: There were 28 patients with achondroplasia, 18 with hypochondroplasia and two with thanatophoric dysplasia type I included in this study. Polymerase chain reaction (PCR), direct sequencing, and amplification created restriction site (ACRS) tests were performed to analyze the mutations on FGFR3 in these patients. Results: Genetic homogeneity of achondroplasia was demonstrated as recurrent G380R mutations in all patients hitherto reported. Although all detected mutations of hypochondroplasia were accounted for by a recurrent N540K mutation in the first tyrosine kinase domain of the receptor, a significant portion (45%) of our patients did not harbor the N540K mutation. Two patients with type I thanatophoric dysplasia were found to carry the R248C mutation. Conclusions: We used either a natural restriction enzyme site or ACRS to detect the recurrent G380R mutation of achondroplasia. The use of the ACRS was found to be more cost-effective and efficient than the use of the natural restriction enzyme digest.

Persistent short stature, other potential outcomes, and the effect of growth hormone treatment in children who are born small for gestational age.

Disclosure: L.D. Cellin: None. K.G. Guimaraes: None. N.L. Menezes De Andrade: None. G.A. Vasques: None. E.D. Goiano: None. M. Akkari: None. C. Santili: None. A.A. Jorge: None. A.C. Malaquias: None. Introduction: COL2A1 is the primary collagen synthesized by chondrocytes and plays a critical structural role in regulating cell growth, differentiation, and migration. Mutations in the COL2A1 gene may cause heterogeneous phenotypes ranging from skeletal dysplasia to nonsyndromic short stature. Clinical characteristics in COL2A1-related disorders are abnormalities in the ocular, skeletal, oro-facial, and audiological systems. Unfortunately, data were scarce about GH treatment in short children with pathogenic variants in COL2A1.Objective: To evaluate recombinant growth hormone (GH) treatment in short children carrying mutations in the COL2A1 gene. Methods: Retrospectively, we selected 8 prepubertal patients with short stature and pathogenic variants in the COL2A1 gene who were treated with GH (mean dose of 45.8 ± 7.9 µg/kg/d at the start). The primary outcomes were changes in height SDS and growth velocity in the 1st year and at the end of treatment. Results: Five patients were male; 3 were disproportionate, and 5 showed skeletal dysplasia signs. Two had familial short stature. At the start of the treatment, the mean calendar age was 8.1 ± 3.9 yr, and bone age was 6.9 ± 4.2 yr. The mean height SDS was -4.0 ± 0.9 for the CDC reference. In the 1st year of therapy, the growth velocity (GV) increased from baseline values of 5.2 ± 1.9 cm/yr to 7.4 ± 1.4cm/yr, an increment of 2.2 ± 2.2cm (p=0.02). GV SDS increased from -1.2 ± 1.5 to 1.2 ± 1.8 in the whole cohort during the 1st year of treatment (p=0.02). Height SDS showed a modest improvement after one year of therapy (from -4.0 ± 0.9 to -3.5 ± 0.9; p=0.005). To improve adult height, we treated two patients with GnRH analogs associated with GH. After a mean duration of therapy of 5.5 ± 2.5 years, 5 patients ended the treatment with rhGH (one prematurely stopped therapy due to poor growth response). No increment was observed in height SDS at the end of treatment (from -3.8 ± 0.9 to -3.4 ± 1.3; p=0.2). Four patients achieved adult height after 6.4 ± 1.7 years of therapy (height SDS ranging from -3.4 ± 0.4 to -2.9 ± 0.8; p=0.08). The mean gain in adult height SDS was 0.5 ± 0.4 (ranging from zero to 0,97). Conclusions: Our patients with COL2A1-associated disorders showed no response to GH therapy to improve adult height as a group. However, we need more studies to determine which patient will benefit from this treatment once there is considerable phenotype heterogeneity. GnRH analogs may help to improve adult height in association with GH. Also, alternative therapies might be evaluated to treat short children with these disorders. Presentation: Thursday, June 15, 2023

The efficacy of growth hormone (GH) treatment in children with idiopathic growth failure has been the subject of controversy because of ethical concerns (1,2), financial considerations (3) and variable adult height outcomes (4,5). Much of the disagreement about the benefits of GH treatment relates to the heterogeneity of the study populations receiving therapy. Ideally, the efficacy of GH therapy should be based on the height outcomes of homogeneous populations of pathologically short children rather than the adult heights of children with variable shortness of differing etiologies. Published studies have sometimes combined children who had constitutional delay of growth and adolescence with subjects who had either severe genetic short stature or significant growth failure growth failure based on abnormal heights and growth rates for chronological age. These short children have been classified by various terminologies: Normal Variant Short Stature (NVSS), Idiopathic Short Stature (ISS), Constitutional Delay of Growth and Puberty (CGDP), GH neurosecretory dysfunction, idiopathic growth failure, and non-GH deficient short stature. Without treatment, the height outcomes in most studies have failed to reach mid-parental target height. In contrast, GH therapy has resulted in mixed height outcomes; some patients reached or exceeded genetic target height whereas others did not. Given the high cost and potential risk of adverse events, some authors have criticized the use of GH in healthy very short children without a documented endocrine disorder (1). Some of this disagreement may be resolved as we improve our ability to identify mutations in various growth regulating genes such as SHOX, GHRH, Ghrelin, GHRP, Pit-1, Prop-1, GH and their receptors.

Achondroplasia (ACH) is the most common form of skeletal dysplasia causing rhizomelic, short-limb short stature. Short- and long-term clinical trials have been conducted with rhGH, with similar results across these studies. At supraphysiological dose of GH, height gain of 1-1.5 SDS on the population curve was observed during the first 1-3 years, which was then followed by a smaller increase in growth rate persisting for 5-6 years. These studies led to the approval of rhGH for ACH in Japan where rhGH has been used for 20 years at 0.05 mg/kg/day. Although the available data are still limited, compared to untreated controls, total gain in adult height has been greater in males than in females, reported at 3.5-8.0 cm and 2.8-4.2 cm, respectively. Serious adverse events have been rare although some were potentially life-threatening and need careful monitoring. These results should serve as a comparator for novel emerging treatments for ACH.

This study presents the results of 38 hip prostheses in 24 people of short stature (under 152 cm). A retrospective clinical and radiological study recording the diagnosis, age at reconstruction, height, weight, type of prostheses, length of follow-up, radiological appearances and patient satisfaction was performed. Harris hip scores were used to assess activities of daily living (1). All patients were under 152cm and their diagnoses included achondroplasia, spondyloepiphyseal dysplasia, multiple epiphyseal dysplasia, developmental dysplasia of the hip and juvenile chronic arthritis. The mean height of these patients was 135 cm (range: 109cm to 150cm). The mean age was 38 years (range: 19 to 75 years) with mean follow-up 67 months (range: 12 to 406 months). Only one patient, who is now aged 69 years (though 65 years at revision surgery), has required revision surgery to date. The results were excellent for 33 hips (Harris hip score between 80–100), good in three (Harris hip score between 70–80), satisfacto...

The effects of recombinant human growth hormone (rhGH) treatment for three years were compared in patients with achondroplasia (ACH) and hypochondroplasia (HCH), whose diagnosis had been confirmed by DNA analysis of the fibroblast growth factor receptor 3 gene. Height SDS (H-SDS) and height velocity SDS (HV-SDS) using the standard for ACH significantly improved during three-year treatment as compared with that before treatment in both ACH and HCH except HV-SDS in the third year. The improvement was much greater in HCH than in ACH. The mean increase H-SDS using the standard for ACH in three years in ACH (from -0.2 SD to 0.1 SD) is almost negligible but that in HCH (from 1.2 SD to 2.6 SD) can be estimated as effective clinically. It can be concluded short-term GH treatment in HCH is effective to increase growth rate and H-SDS, but it has little effect in ACH. Further studies would be required to confirm the other beneficial effects of GH treatment such as increase in bone mineral density in ACH and HCH and the effect on the final height.

Patients with mucopolysaccharidoses (MPS) have accumulation of glycosaminoglycans in multiple tissues which may cause coarse facial features, mental retardation, recurrent ear and nose infections, inguinal and umbilical hernias, hepatosplenomegaly, and skeletal deformities. Clinical features related to bone lesions may include marked short stature, cervical stenosis, pectus carinatum, small lungs, joint rigidity (but laxity for MPS IV), kyphoscoliosis, lumbar gibbus, and genu valgum. Patients with MPS are often wheelchair-bound and physical handicaps increase with age as a result of progressive skeletal dysplasia, abnormal joint mobility, and osteoarthritis, leading to: (I) stenosis of the upper cervical region; (II) restrictive small lung; (III) hip dysplasia; (IV) restriction of joint movement; and (V) surgical complications. Patients often need multiple orthopedic procedures including cervical decompression and fusion, carpal tunnel release, hip reconstruction and replacement, and femoral or tibial osteotomy through their lifetime. Current measures to intervene in bone disease progression are not perfect and palliative, and improved therapies are urgently required. Enzyme replacement therapy (ERT), hematopoietic stem cell transplantation (HSCT), and gene therapy are available or in development for some types of MPS. Delivery of sufficient enzyme to bone, especially avascular cartilage, to prevent or ameliorate the devastating skeletal dysplasias remains an unmet challenge. The use of an anti-inflammatory drug is also under clinical study. Therapies should start at a very early stage prior to irreversible bone lesion, and damage since the severity of skeletal dysplasia is associated with level of activity during daily life. This review illustrates a current overview of therapies and their impact for bone lesions in MPS including ERT, HSCT, gene therapy, and anti-inflammatory drugs.

Premature mortality and hypopituitarism

Reply

Achondroplasia (ACH) is the most common form of skeletal dysplasia characterized by disproportionately short stature, lumbar lordosis, relative macrocephaly and other skeletal anomalies resulting from a defect in the maturation of the chondrocytes in the growth plate of the cartilage. The combined frequency of the disease has been estimated to be 1 in 15 000 live births.

Growth hormone (GH) replacement has been offered to GH-deficient (GHD) children for approximately 40 years whereas it has only been a licensed indication for the treatment of GHD adults since 1996. Nonetheless, the advent of GH replacement for adult GHD patients (Jorgensen et al., 1989; Salomon et al., 1989) has proved informative about the overall management of the GHD child and teenager; equally, the longstanding experience of the paediatric endocrinologist with GH replacement has provided some guidance about potential pitfalls in the diagnosis and management of the adult GHD patient. It is the knowledge exchange at this professional interface that forms the focus of this article.

The approved therapeutic dose of growth hormone (GH) for growth hormone deficiency (GHD) varies depending on the country. Japan has the lowest therapeutic dose globally, with a single dose of 0.175 mg/kg/week. GH treatment for GHD is considered as a replacement therapy and in fact, a dose of 0.175 mg/kg/week is slightly higher than GH secretion in prepubertal healthy children but nearly the same as that of pubertal children. Although the same growth rate as that of healthy children is expected in response to replacement therapy, the catch-up growth observed for the first 1 to 2 years of GH treatment was misinterpreted as an effect of the GH replacement therapy. The real effect of the GH replacement therapy was the growth rate appeared after more than 3 years of GH therapy, when patients showed nearly the same growth rate as healthy children. Therefore, children with GHD can have a higher growth rate than healthy children only for the first 1 to 2 years of GH therapy, after which their growth rate begins to wane. In the United States and Europe, the various therapeutic doses and high-dose treatment are accepted and the SD score of adult height after treatment is higher than that in Japan. The improvement degree of the height SD score and the adult height SD score with GH therapy are lower in Japan compared with other countries that administer a similar therapeutic dose. This suggests that the response to GH can be affected by race. Actual comparison of the response to GH between Japanese and Caucasian patients using KIGS (Pharmacia International Growth Database) data showed that both the short-term response and the effect on adult height were reduced in Japanese patients. As there is a strong positive correlation between adult height and height at the onset of puberty, treatment methods that can increase pubertal growth will be considered in the future for patients with GDH who enter puberty with short stature.