Heritable Diseases of Connective Tissue

100%

Heritable Diseases of Connective Tissue

KEY POINTS

Heritable disorders of connective tissues are a genetically diverse group of disorders and are associated with extreme variation in height, from very short individuals (dwarves) to those with tall stature.

The osteochondrodysplasias or skeletal dysplasias are a group of more than four hundred fifty distinct disorders frequently associated with profound short stature and orthopedic complications.

These disorders are diagnosed based on radiographic, clinical, and molecular criteria.

There has been significant progress in elucidating the underlying molecular mechanisms in most of these disorders, providing for improved clinical diagnosis and reproductive choices for affected individuals and their families.

Treatment options have been used in osteogenesis imperfecta, metabolic storage disorders, and Marfan syndrome, which may improve the quality of life and life span in affected individuals.

Heritable disorders of connective tissues are a heterogenous group of disorders characterized by abnormalities in skeletal tissues, which include cartilage, bone, tendon ligament, and muscle. Disorders of connective tissues have been classified based on clinical findings and molecular criteria. They are subclassified into those that primarily affect cartilage and bone, which are the skeletal dysplasias, and those that have a more profound effect on connective tissue, which include the Ehlers-Danlos syndrome, Marfan syndrome, and other disorders caused by abnormal extra-cellular matrix molecules, such as cutis laxa syndrome resulting from mutations in the gene that encodes fibulin five. The skeletal dysplasias are associated with abnormalities in the size and shape of the appendicular and axial skeleton and frequently result in disproportionate short stature. Until the early nineteen sixties, most individuals with short stature were considered to have pituitary dwarfism, achondroplasia (short-limbed dwarfism), or Morquio disease (short-trunked dwarfism). Presently, there are more than four hundred fifty well-characterized disorders that are classified primarily on the basis of clinical, radiographic, and molecular criteria. Disorders of connective tissues are genetic in origin and result from mutations in genes that encode extra-cellular matrix proteins, transcription factors, tumor suppressors, signal transducers, enzymes, chaperones, intra-cellular binding proteins, R N A-processing molecules, ciliary proteins, and genes of unknown function.

SKELETAL DYSPLASIAS

The skeletal dysplasias, or osteochondrodysplasias, are defined as disorders associated with a generalized abnormality in the skeletal. Although each skeletal dysplasia is relatively rare, collectively the birth incidence of these disorders is almost one in five thousand. These disorders range in severity from precious arthropathy to perinatal lethality caused by pulmonary insufficiency. Individuals with these disorders can have significant complications, including orthopedic, neurologic, and psychological. Many of these individuals seek medical attention for orthopedic complaints from ongoing pain, arthritic complaints in large joints, and back pain primarily caused by ongoing abnormalities in bone, cartilage, tendons, and ligaments.

Embryology

Cartilage Structure

Dysplasia

Dyssegmental dysplasia

Classification and Nomenclature

Clinical Evaluation and Features

Diagnostic Tests and Diagnosis

Treatment

Biochemical and Molecular Abnormalities

DEFECTS IN EXTRA-CELLULAR STRUCTURAL PROTEINS

Cartilage Oligomeric Matrix Protein

Conclusion

Osteogenesis Imperfecta

Mild Osteogenesis Imperfecta (Type One OI)

Molecular Pathology

Lethal Osteogenesis Imperfecta, Type two OI

Molecular Pathology

Severely Deforming Osteogenesis Imperfecta, Type three OI

Molecular Pathology

Osteogenesis Imperfecta of Moderate Severity (Type Four OI)

Molecular Pathology

Type Five Osteogenesis Imperfecta

Histopathology of Bone in Osteogenesis Imperfecta

Treatment

EHLERS-DANLOS SYNDROME

Ehlers-Danlos Syndrome (Classic Type)

Ehlers-Danlos Syndrome (Hypermobility Type)

Structural and Molecular Pathology of the Classic and Hypermobile Type of Ehlers-Danlos Syndrome

Ehlers-Danlos Syndrome (Vascular Type)

Molecular Pathology

Therapy in the Classic, Hypermobility, and Vascular Types of Ehlers-Danlos Syndrome

Arthrochalasia Type

Molecular Pathology

Ehlers-Danlos Syndrome (Dermatosparaxis Type)

Ehlers-Danlos Syndrome (Kyphoscoliosis Type)

Molecular Pathology

Other Ehlers-Danlos Syndrome Types

MARFAN SYNDROME

Differential Diagnosis

Molecular Biology of Marfan Syndrome

Treatment

LOEYS-DIETZ SYNDROME

CONGENITAL CONTRACTURAL ARACHNODACTYLY

CONCLUSION

Overview

The document explores the genetically diverse group of heritable connective tissue disorders, known for causing significant variation in height and skeletal abnormalities. It discusses the classification, diagnosis, and molecular mechanisms underlying these disorders, as well as available treatment options to improve quality of life.

Key Points

1Heritable connective tissue disorders encompass over four hundred fifty distinct conditions
2These disorders lead to significant variations in height and skeletal abnormalities
3Diagnosis is based on radiographic, clinical, and molecular criteria
4Treatment options exist for conditions like osteogenesis imperfecta and Marfan syndrome
5Accurate diagnosis can impact reproductive decisions for affected families

Details

Category: Health and Medicine

PDF
Neonatal Disorders
This document provides a comprehensive overview of neonatal disorders, including case scenarios and learning objectives targeted at third-year medical students. It outlines essential management plans and assessment procedures for common neonatal conditions.
PDF
13. Gross Anatomy: Muscles of the Hand
This document outlines the anatomy of the intrinsic muscles of the hand, detailing their compartments and clinical significance, particularly in relation to carpal tunnel syndrome and recurrent branch injuries.
PDF
12. Gross Anatomy: RA Upper Extremities
This document outlines a detailed guide on gross anatomy focused on the upper extremities, covering the shoulder, humerus, elbow, forearm, and hand/wrist series with an emphasis on radiographic examination techniques and anatomical considerations.
PDF
11. Gross Anatomy: Compartments of the Forearm
This document outlines the anatomy of the forearm, detailing the anterior and posterior compartments, including the muscles, their origins, insertions, innervation, and actions. It serves as a comprehensive guide for students studying gross anatomy.
PDF
10. Gross Anatomy: Bones and Muscles of the Shoulder and Arm
This document outlines the anatomy of the shoulder and arm, including details on the muscles and bones, their origins, insertions, innervations, and primary actions. It provides learning objectives that aim to enhance students' understanding of arm anatomy.