Growth in individuals with Saul-Wilson syndrome

Growth Charts for Children With Arthrogryposis Multiplex Congenita

Children with arthrogryposis multiplex congenita (AMC) often demonstrate growth differences compared with typically developing (TD) children. However, growth charts have not been developed for this population. The purpose of this study was to create AMC-specific growth charts and to compare these values to those of TD children. A retrospective review of height/length and weight for 206 children with AMC was performed. Growth charts were developed and stratified over seven percentiles; these were then compared with growth charts of TD children. Children with AMC tend to be smaller in stature and weight compared with TD children, particularly in the first 36 months of life. Thereafter, weight values trend toward the 50th percentile of TD children, but height/length values persist around the 5th percentile of TD children. The development of AMC-specific growth charts provides health care providers an objective tool to evaluate growth patterns of patients with AMC.

A scoping review of nutrition issues and management strategies in individuals with skeletal dysplasia

PURPOSE

Skeletal dysplasia are heterogeneous conditions affecting the skeleton. Common nutrition issues include feeding difficulties, obesity, and metabolic complications. This systematic scoping review aimed to identify key nutrition issues, management strategies, and gaps in knowledge regarding nutrition in skeletal dysplasia.

METHODS

The databases Ovid MEDLINE, Ovid EMBASE, Ebsco CINAHL, Scopus, and Cochrane Central Register of Controlled Trials and Database of Systematic Reviews were searched. Reference lists and citing literature for included studies were searched. Eligible studies included participants with skeletal dysplasia and described: anthropometry, body composition, nutrition-related biochemistry, clinical issues, dietary intake, measured energy or nutrition requirements, or nutrition interventions.

RESULTS

The literature search identified 8509 references from which 138 studies were included (130 observational, 3 intervention, 2 systematic reviews, and 3 clinical guidelines). Across 17 diagnoses identified, most studies described osteogenesis imperfecta (n = 50) and achondroplasia or hypochondroplasia (n = 47). Nutrition-related clinical issues, biochemistry, obesity, and metabolic complications were most commonly reported, and few studies measured energy requirements (n = 5).

CONCLUSION

Nutrition-related comorbidities are documented in skeletal dysplasia; yet, evidence to guide management is scarce. Evidence describing nutrition in rarer skeletal dysplasia conditions is lacking. Advances in skeletal dysplasia nutrition knowledge is needed to optimize broader health outcomes.

Ocular symptoms of Saul — Wilson syndrome in children

The genetic Saul — Wilson syndrome is so rare that the very few descriptions of its ocular manifestations available are of high clinical interest. Purpose. To offer a description of the ocular manifestations of the Saul — Wilson syndrome. Material and methods. Two children with a verified diagnosis of Saul — Wilson syndrome, observed from the age of 3 and 4 (the follow-up period was 6 months to 2.5 years), were subjected to a comprehensive ophthalmological examination. Results. The children, along with characteristic phenotypic manifestations (clubfoot, very short stature, short fingers and toes, hypermobile joints) were found to have a disordered visual system, associated with the particularities of the facial skeleton (exophthalmos or strabismus) and clinical and functional eye disorders: mild hypermetropia, hypermetropic astigmatism, partial complicated cataract. One child was diagnosed with changes in the structure and function of the retina, which indicates a dystrophic process. The diagnosis was genetically verified. Conclusion. Given the rarity of the disease, multiple organ involvement, an uncertain prognosis, an interdisciplinary approach to the management of such patients, constant dynamic monitoring and timely correction of detected disorders is necessary.

COG4 mutation in Saul-Wilson syndrome selectively affects secretion of proteins involved in chondrogenesis in chondrocyte-like cells

Saul-Wilson syndrome is a rare skeletal dysplasia caused by a heterozygous mutation in COG4 (p.G516R). Our previous study showed that this mutation affected glycosylation of proteoglycans and disturbed chondrocyte elongation and intercalation in zebrafish embryos expressing the COG4^p.G516R variant. How this mutation causes chondrocyte deficiencies remain unsolved. To analyze a disease-relevant cell type, COG4^p.G516R variant was generated by CRISPR knock-in technique in the chondrosarcoma cell line SW1353 to study chondrocyte differentiation and protein secretion. COG4^p.G516R cells display impaired protein trafficking and altered COG complex size, similar to SWS-derived fibroblasts. Both SW1353 and HEK293T cells carrying COG4^p.G516R showed very modest, cell-type dependent changes in N-glycans. Using 3D culture methods, we found that cells carrying the COG4^p.G516R variant made smaller spheroids and had increased apoptosis, indicating impaired in vitro chondrogenesis. Adding WT cells or their conditioned medium reduced cell death and increased spheroid sizes of COG4^p.G516R mutant cells, suggesting a deficiency in secreted matrix components. Mass spectrometry-based secretome analysis showed selectively impaired protein secretion, including MMP13 and IGFBP7 which are involved in chondrogenesis and osteogenesis. We verified reduced expression of chondrogenic differentiation markers, MMP13 and COL10A1 and delayed response to BMP2 in COG4^p.G516R mutant cells. Collectively, our results show that the Saul-Wilson syndrome COG4^p.G516R variant selectively affects the secretion of multiple proteins, especially in chondrocyte-like cells which could further cause pleiotropic defects including hampering long bone growth in SWS individuals.