Designing collagens to shed light on the multi-scale structure-function mapping of matrix disorders

Collagens are the most abundant structural proteins in the extracellular matrix of animals and play crucial roles in maintaining the structural integrity and mechanical properties of tissues and organs while mediating important biological processes. Fibrillar collagens have a unique triple helix structure with a characteristic repeating sequence of (Gly-X-Y)n. Variations within the repetitive sequence can cause misfolding of the triple helix, resulting in heritable connective tissue disorders. The most common variations are single-point missense mutations that lead to the substitution of a glycine residue with a bulkier amino acid (Gly → X). In this review, we will first discuss the importance of collagen's triple helix structure and how single Gly substitutions can impact its folding, structure, secretion, assembly into higher-order structures, and biological functions. We will review the role of "designer collagens," i.e., synthetic collagen-mimetic peptides and recombinant bacterial collagen as model systems to include Gly → X substitutions observed in collagen disorders and investigate their impact on structure and function utilizing in vitro studies. Lastly, we will explore how computational modeling of collagen peptides, especially molecular and steered molecular dynamics, has been instrumental in probing the effects of Gly substitutions on structure, receptor binding, and mechanical stability across multiple length scales.

Ehlers-Danlos syndrome: how to diagnose and when to perform genetic tests

The term Ehlers-Danlos syndrome (EDS) encompasses a group of inherited connective tissue disorders. The manifestations of EDS can be seen in skin, joints, blood vessels and internal organs and vary from mild to severe and life threatening. Each subtype is a separate and different condition. The genetic basis of many subtypes has now been elucidated, confirming heterogeneity. An awareness of the different conditions within this group is the starting point towards accurate diagnosis. Accurate elicitation of history and clinical signs is vital in selecting the correct confirmatory investigation. Skin biopsy with electron microscopy can be helpful in the decision process of whether and when to perform genetic testing. Correct diagnosis within the EDSs allows targeted management, family screening and prenatal diagnosis.

Recent advances in paediatric dermatology

The past year has produced several new clinical guidelines germane to paediatric dermatology, as well as important work related to rheumatologic overlap disorders, psoriasis comorbidities, pigmented lesions and quality of life impact. This review highlights common diagnoses and treatments useful for the practicing paediatrician.