Clinical Characteristics of Short-Stature Patients With Collagen Gene Mutation and the Therapeutic Response to rhGH

Two cases of autosomal dominant familial short stature associated with COL11A2 gene variant and the therapeutic response to recombinant human growth hormone

Background

Variants in collagen genes can cause diverse growth plate disorders frequently associated with short stature. This study aimed to evaluate clinical phenotypes in two autosomal dominant familial short stature (AD-FSS), along with the responses to recombinant human growth hormone (rhGH).

Methods

Two AD-FSS children treated with rhGH from two families were included. Next-generation sequencing (NGS) was performed to screen the gene variants that may be related to short stature. The genetic test results were evaluated using the guidelines set by the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP). The response of the children to rhGH was evaluated.

Results

The first case (child 1) was a girl aged 8 years and 7 months with a height of 118.8 cm. Her mother had a height of 145 cm. The child's maternal aunt, grandmother, grandmother's sisters, and great-grandmother were also under 150 cm in height, sharing the characteristic of short limbs. NGS revealed a c.688G>T heterozygous variant in exon 5 of the COL11A2 gene for the girl and her mother. The second case (child 2) was a boy aged 4 years and 8 months with a height of 96 cm. A heterozygous variant c.2458G>A in exon 32 of the COL11A2 gene was identified in the boy and his father. After 18 and 19 months of rhGH treatment, their heights increased by 15 and 20 cm, respectively, with no adverse events.

Conclusions

We presented two AD-FSS cases carrying the c.688G>T variant in exon 5 and the c.2458G>A variant in exon 32 of the COL11A2 gene, respectively. The short-term response to rhGH treatment is promising for AD-FSS children.

Clinical Features of Seven COL2A1 Variations in Chinese Children With Type II Collagen Disorders

AIM

Type II collagen, encoded by the collagen type II alpha 1 (COL2A1) gene, is crucial for the structure of cartilage. This study aims to improve our understanding of Spondyloepiphyseal Dysplasia Congenita (SEDC) caused by mutations in COL2A1. We also aim to evaluate the safety and efficacy of growth hormone (GH) therapy in two SEDC patients.

METHODS

We performed genetic analyses of seven paediatric patients from unrelated Chinese families. Two patients received GH therapy, and their growth trajectories were monitored over 3.5 and 3 years.

RESULTS

Genetic screening identified six missense mutations (Gly1110Ser, Gly1107Glu, Gly873Arg, Gly456Ala, Gly1062Ser and Gly1182Arg) and one intron variant in COL2A1. All patients (five girls and two boys, ranging from 2 years and 7 months to 12 years) were diagnosed with SEDC, exhibiting disproportionate short stature and skeletal abnormalities. GH therapy resulted in height increases of 0.76 and 0.27 standard deviation scores over 3.5 and 3 years, respectively, with no significant side effects.

CONCLUSION

This study expands the mutation spectrum of COL2A1 and supports the efficacy and safety of GH therapy in SEDC patients, highlighting the need for multi-center studies to further investigate GH's therapeutic potential.

A genomic strategy for precision medicine in rare diseases: integrating customized algorithms into clinical practice

BACKGROUND

Despite the use of Next-Generation Sequencing (NGS) as the gold standard for the diagnosis of rare diseases, its clinical implementation has been challenging, limiting the cost-effectiveness of NGS and the understanding, control and safety essential for decision-making in clinical applications. Here, we describe a personalized NGS-based strategy integrating precision medicine into a public healthcare system and its implementation in the routine diagnosis process during a five-year pilot program.

METHODS

Our approach involved customized probe designs, the generation of virtual panels and the development of a personalized medicine module (PMM) for variant prioritization. This strategy was applied to 6500 individuals including 6267 index patients and 233 NGS-based carrier screenings.

RESULTS

Causative variants were identified in 2061 index patients (average 32.9%, ranging from 12 to 62% by condition). Also, 131 autosomal-recessive cases could be partially genetically diagnosed. These results led to over 5000 additional studies including carrier, prenatal and preimplantational tests or pharmacological and gene therapy treatments.

CONCLUSION

This strategy has shown promising improvements in the diagnostic rate, facilitating timely diagnosis and gradually expanding our services portfolio for rare diseases. The steps taken towards the integration of clinical and genomic data are opening new possibilities for conducting both retrospective and prospective healthcare studies. Overall, this study represents a major milestone in the ongoing efforts to improve our understanding and clinical management of rare diseases, a crucial area of medical research and care.

Preliminary investigation into the genetic etiology of short stature in children through whole exon sequencing of the core family

A comprehensive survey was carried out to investigate the genetic etiology of short stature in children by whole exon sequencing of a core family cohort to find and study mutations in multiple genes to assess their potential correlations to low height in children. The study included 56 pediatric patients from the Department of Pediatrics at the Zhangzhou Affiliated Hospital of Fujian Medical University. The participants met strict inclusion criteria, including age, Han Chinese ethnicity, low height standard deviation score, and the absence of known causes for short stature. Core pedigrees were identified using exome sequencing. After sequencing, variations were categorized and interpreted according to a variety of factors, including inheritance, location, type, and disease-causing gene databases. Variants were verified by Sanger sequencing. Most of the 97 gene mutations were missense. ACAN, PHEX, and COL2A1 were the most common gene mutations. Copy number variations were identified, particularly associated with the PHEX gene. Protein functional studies revealed that the mutations had a considerable influence on disease-promoting damage. The chromosomal locations with the highest enrichment of these genes were chr12, chr5, and chr2. In conclusion, the study revealed numerous genetic changes that may substantially impact physiological processes and disease. These findings establish the basis for further investigations into their diagnostic and therapeutic capabilities.

The health-care utilization and economic burden in patients with genetic skeletal disorders

BACKGROUND

Most genetic skeletal disorders (GSD) were complex, disabling and life-threatening without effective diagnostic and treatment methods. However, its impacts on health system have not been well studied. The study aimed to systematically evaluate the health-care utilization and economic burden in GSD patients.

METHODS

The patients were derived from 2018 Nationwide Inpatient Sample and Nationwide Readmissions Database. GSD patients were extracted based on International Classification of Diseases-10th revision codes.

RESULTS

A total of 25,945 (0.12%) records regarding GSD were extracted from all 21,400,282 records in NIS database. GSD patients were likely to have significantly longer length of stay (6.50 ± 0.08 vs. 4.63 ± 0.002, P < 0.001), higher total charges ($85,180.97 ± 1,239.47 vs. $49,884.26 ± 20.99, P < 0.001), suffering more procedure, diagnosis and transferring records in comparison to patients with common conditions. GSD patients had a significantly higher 30-day all-cause readmission rate based on Nationwide Readmissions Database.

CONCLUSIONS

The heavy health-care utilization and economic burden emphasized the urgency for policy leaders, scientific and pharmaceutical researchers, health care providers and employers to identify innovative ways and take effective measurements immediately, and eventually to help improve the care, management, and treatment of these devastating diseases.

Exploring the Genetic Causes for Postnatal Growth Failure in Children Born Non-Small for Gestational Age

The most common causes of short stature (SS) in children are familial short stature (FSS) and idiopathic short stature (ISS). Recently, growth plate dysfunction has been recognized as the genetic cause of FSS or ISS. The aim of this study was to investigate monogenic growth failure in patients with ISS and FSS. Targeted exome sequencing was performed in patients categorized as ISS or FSS and the subsequent response to growth hormone (GH) therapy was analyzed. We found 17 genetic causes involving 12 genes (NPR2, IHH, BBS1, COL1A1, COL2A1, TRPS1, MASP1, SPRED1, PTPTN11, ADNP, NADSYN1, and CERT1) and 2 copy number variants. A genetic cause was found in 45.5% and 35.7% of patients with FSS and ISS, respectively. The genetic yield in patients with syndromic and non-syndromic SS was 90% and 23.1%, respectively. In the 11 genetically confirmed patients, a gain in height from -2.6 to -1.3 standard deviations after 2 years of GH treatment was found. The overall diagnostic yield in this study was 41.7%. We identified several genetic causes involving paracrine signaling, the extracellular matrix, and basic intracellular processes. Identification of the causative gene may provide prognostic evidence for the use of GH therapy in non-SGA children.

An Analysis of the Gene Expression Associated with Lymph Node Metastasis in Colorectal Cancer

Objective

This study aimed to explore the genes regulating lymph node metastasis in colorectal cancer (CRC) and to clarify their relationship with tumor immune cell infiltration and patient prognoses.

Methods

The data sets of CRC patients were collected through the Cancer Gene Atlas database; the differentially expressed genes (DEGs) associated with CRC lymph node metastasis were screened; a protein-protein interaction (PPI) network was constructed; the top 20 hub genes were selected; the Gene Ontology functions and the Kyoto Encyclopedia of Genes and Genomes pathways were enriched and analyzed. The Least Absolute Shrinkage and Selection Operator (LASSO) regression method was employed to further screen the characteristic genes associated with CRC lymph node metastasis in 20 hub genes, exploring the correlation between the characteristic genes and immune cell infiltration, conducting a univariate COX analysis on the characteristic genes, obtaining survival-related genes, constructing a risk score formula, conducting a Kaplan-Meier analysis based on the risk score formula, and performing a multivariate COX regression analysis on the clinical factors and risk scores.

Results

A total of 62 DEGs associated with CRC lymph node metastasis were obtained. Among the 20 hub genes identified via PPI, only calcium-activated chloride channel regulator 1 (CLCA1) expression was down-regulated in lymph node metastasis, and the rest were up-regulated. A total of nine characteristic genes associated with CRC lymph node metastasis (KIF1A, TMEM59L, CLCA1, COL9A3, GDF5, TUBB2B, STMN2, FOXN1, and SCN5A) were screened using the LASSO regression method. The nine characteristic genes were significantly related to different kinds of immune cell infiltration, from which three survival-related genes (TMEM59L, CLCA1, and TUBB2B) were screened. A multi-factor COX regression showed that the risk scores obtained from TMEM59L, CLCA1, and TUBB2B were independent prognostic factors. Immunohistochemical validation was performed in tissue samples from patients with rectal and colon cancer.

Conclusion

TMEM59L, CLCA1, and TUBB2B were independent prognostic factors associated with lymphatic metastasis of CRC.

Idiopathic Short Stature: What to Expect from Genomic Investigations

Short stature is a common concern for physicians caring for children. In traditional investigations, about 70% of children are healthy, without producing clinical and laboratory findings that justify their growth disorder, being classified as having constitutional short stature or idiopathic short stature (ISS). In such scenarios, the genetic approach has emerged as a great potential method to understand ISS. Over the last 30 years, several genes have been identified as being responsible for isolated short stature, with almost all of them being inherited in an autosomal-dominant pattern. Most of these defects are in genes related to the growth plate, followed by genes related to the growth hormone (GH)–insulin-like growth factor 1 (IGF1) axis and RAS-MAPK pathway. These patients usually do not have a specific phenotype, which hinders the use of a candidate gene approach. Through multigene sequencing analyses, it has been possible to provide an answer for short stature in 10–30% of these cases, with great impacts on treatment and follow-up, allowing the application of the concept of precision medicine in patients with ISS. This review highlights the historic aspects and provides an update on the monogenic causes of idiopathic short stature and suggests what to expect from genomic investigations in this field.

Clinical and molecular characterization of a patient with MBTPS1 related spondyloepiphyseal dysplasia: Evidence of pathogenicity for a synonymous variant

BACKGROUND

A novel autosomal recessive skeletal dysplasia resulting from pathogenic variants in membrane-bound transcription factor peptidase, site 1 (MBTPS1) has been recently delineated. To date, only three patients have been reported.

METHODS

In this study, we reported the clinical and molecular features of a Chinese boy who was diagnosed with spondyloepiphyseal dysplasia. The effects of variants on mRNA splicing were analyzed through transcript analysis in vivo and minigene splice assay in vitro.

RESULTS

The proband mainly showed short stature, special facial features, cataract, hernias, and serious sleep apnea syndrome. Growth hormone stimulation tests suggested the boy had growth hormone deficiency. Imaging examinations suggested abnormal thoracolumbar vertebrae and severely decreased bone mineral density. Genetic analysis of MBTPS1 gene revealed two novel heterozygous variants, a nonsense mutation c.2656C > T (p.Q886*, 167) in exon 20 and a synonymous variant c.774C > T (p.A258=) in exon 6. The transcript analysis in vivo exhibited that the synonymous variant c.774C > T caused exon 6 skipping. The minigene splice assay in vitro confirmed the alteration of MBTPS1 mRNA splicing and the exon skipping was partially restored by an antisense oligonucleotide (ASO) treatment.

CONCLUSION

Notably, we report a Chinese rare case of spondyloepiphyseal dysplasia and validate its pathogenic synonymous variant in the MBTPS1 gene.