60 Questions
What percentage of diseases could be passed from the parents to the offspring?
Around 80%
What is the main cause of whether genetic disorders appear or not?
Environmental factors
What is the approximate frequency of occurrence of most genetic disorders?
One person in every several thousands or millions
What type of mutations may cause defects in some genetic disorders?
New mutations
What must happen for a genetic defect to be passed down in the case of new mutations?
It occurs in the germline
What is the intended audience for the contents of the lecture?
BSc (Hons) students of TWC only
What is the most common nonlethal skeletal dysplasia?
Achondroplasia
Which gene mutation is responsible for Achondroplasia?
G380R mutation in the FGFR3 gene
What is a common characteristic of Osteogenesis imperfecta?
Bone fragility and susceptibility to fractures
What are symptoms of bone tumors?
Increasing pain, fatigue, fever, weight loss, anemia
Where are many primary bone tumors commonly found?
Distal femur and proximal tibia
What is the average five-year survival rate in the United States after a bone and joint cancer diagnosis?
67%
Which genetic disorder has the highest global prevalence?
Sickle cell anemia
What is the incidence rate of Huntington’s Disease in people of European descent?
4-15 in 100,000
Which genetic disorder involves tumors of Schwann cells?
Neurofibromatosis
What is the advantage of having some recessive gene disorders in certain environments?
Survival advantage in specific conditions
In which population is Huntington’s Disease rare?
Japanese/Asian
What type of mutation causes Huntington’s Disease?
Autosomal dominant mutation
Which type of bone tumor often originates in the bone marrow and presents as one or more bone lesions?
Multiple myeloma
What specialized studies are required for the classification of Malignant fibrous histiocytoma (MFH) into other tumor classes?
Genetic and immuno-histochemical tests
Which type of bone tumor typically originates in the midline of the sacrum or coccyx?
Germ cell tumors
What are the common sources of metastatic lesions for secondary bone tumors?
Breast, lung, or prostate
What imaging technique is commonly involved in the diagnosis of bone tumors?
PET-CT
What type of surgery is specifically mentioned as a treatment option for bone tumors?
Limb sparing surgery
Which gene mutations result in the synthesis of truncated EXT proteins, affecting heparan sulfate synthesis and leading to abnormal bone growth and disruption of physeal growth?
EXT1 and EXT2
Which skeletal dysplasia is characterized by short stature, a relatively normal-sized trunk, large head, and rhizomelic shortening of the limbs?
Achondroplasia
Which genetic disorder leads to dysplasia, scaphocephalic macrocephaly, coarse facial features, and joint contractures, with specific radiographic features like hook-shaped deformity of the vertebrae and abnormally shaped tubular bones in the hands?
Hurler syndrome
Which method can be used for the diagnosis of genetic disorders involving examination of genetic material?
Amniocentesis
What are the most common locations for exostoses, with the potential for malignant transformation into chondrosarcoma?
Distal femur, proximal tibia, humerus, and proximal fibula
What are osteochondromas?
Benign bone tumors arising in the metaphysis of long bones
Which genetic disorder is characterized by dysplasia, scaphocephalic macrocephaly, coarse facial features, and joint contractures, with specific radiographic features like hook-shaped deformity of the vertebrae and abnormally shaped tubular bones in the hands?
Thanatophoric dysplasia
What is the approximate percentage of diseases that could be passed from the parents to the offspring?
80%
Which type of bone tumor often originates in the bone marrow and presents as one or more bone lesions?
Osteosarcoma
In which population is Huntington’s Disease rare?
Asian descent
What is the main cause of whether genetic disorders appear or not?
Environmental factors
What specialized studies are required for the classification of Malignant fibrous histiocytoma (MFH) into other tumor classes?
Immunohistochemistry
What is the approximate frequency of occurrence of Achondroplasia globally?
1 in 26,000-28,000 live births
Which gene mutation is responsible for Achondroplasia?
G380R mutation in the FGFR3 gene
What is the most common type of primary bone tumor found in the distal femur and proximal tibia?
Osteoid osteoma
What are the common symptoms of bone tumors?
Increasing pain, fatigue, fever, weight loss, anemia
What is the average five-year survival rate in the United States after a bone and joint cancer diagnosis?
67%
What type of bone tumors can metastasize to the skeleton from other sites?
Secondary tumors
What is the approximate global prevalence of Sickle cell anemia?
1 in 100,000 individuals
Which genetic disorder has the highest global prevalence?
Sickle cell anemia
What is the incidence rate of Huntington’s Disease in people of European descent?
4-15 in 100,000 individuals
What is the approximate incidence rate of Multiple Hereditary Exostosis (HME)?
1 in 50,000 individuals
Which genetic disorder involves tumors of Schwann cells?
Neurofibromatosis
What type of gene mutation causes Huntington’s Disease?
Autosomal dominant gene mutation
Which imaging technique is NOT commonly involved in the diagnosis of bone tumors?
Ultrasound
What is the most common type of malignant primary bone tumor?
Osteosarcoma
Which bone tumor originates in the bone marrow and often presents as one or more bone lesions?
Multiple myeloma
What specialized studies are required for the classification of Malignant fibrous histiocytoma (MFH) into other tumor classes?
Genetic and immuno-histochemical tests
Which type of surgery is specifically mentioned as a treatment option for bone tumors?
Limb sparing surgery
What is the main factor that determines the cure rate for malignant bone tumors?
All of the above
What is the chance of spontaneous mutation in the transmission of skeletal dysplasias to offspring?
20%
Which gene mutation is responsible for affecting heparan sulfate synthesis and leading to abnormal bone growth and disruption of physeal growth in skeletal dysplasias?
EXT3
Which genetic disorder leads to dysplasia, scaphocephalic macrocephaly, coarse facial features, and joint contractures?
Hurler syndrome
What is the main method for the diagnosis of genetic disorders involving examination of genetic material?
Amniocentesis
What are the common locations for exostoses with the potential for malignant transformation into chondrosarcoma?
Distal femur and proximal tibia
What are the distinct clinical and radiographic features of osteogenesis imperfecta?
Short, thick, ribbonlike long bones and multiple fractures
Study Notes
Skeletal Dysplasias and Genetic Disorders: Key Points
- Skeletal dysplasias are heritable disorders characterized by abnormalities in cartilage and bone growth, leading to abnormal skeletal shape and size.
- Osteochondromas are cartilage-capped benign bone tumors that arise in the metaphysis of long bones, leading to bone shortening and bowing, and can cause pain or numbness from nerve compression.
- Most common locations for exostoses are the distal femur, proximal tibia, humerus, and proximal fibula, with the potential for malignant transformation into chondrosarcoma.
- Skeletal dysplasias can be diagnosed through radiographic features and genetic testing of EXT1 and EXT2, with a 50% chance of transmission to offspring and a 10-20% chance of spontaneous mutation.
- Mutations in EXT1, EXT2, and EXT3 genes result in the synthesis of truncated EXT proteins, affecting heparan sulfate synthesis and leading to abnormal bone growth and disruption of physeal growth.
- Skeletal dysplasias can cause joint pain, neurovascular compression, spinal deformities, and autism-like social problems, and may be more severe if the mutation is on the EXT1 gene.
- Diagnosis of genetic disorders involves genetic material examination, in-depth family history, and varied methods such as prenatal diagnosis through fetal development ultrasound or amniocentesis.
- Treatment for skeletal dysplasias includes surgical options like ostechondroma excision, gradual or acute bone lengthening, and corrective osteotomies, as well as gene therapy and supportive therapy.
- Genetic disorders can affect various stages of development and have diverse prognoses, with no known cures at present, requiring maintenance of quality of life and patient autonomy through physiotherapy, pain management, and supportive or alternative medicine programs.
- Common skeletal dysplasias include achondroplasia, osteogenesis imperfecta, thanatophoric dysplasia, campomelic dysplasia, and hypochondroplasia, each with distinct clinical and radiographic features.
- Achondroplasia is characterized by short stature, a relatively normal-sized trunk, large head, and rhizomelic shortening of the limbs, while osteogenesis imperfecta presents with short, thick, ribbonlike long bones and multiple fractures.
- Hurler syndrome, a mucopolysaccharidosis type IH, leads to dysplasia, scaphocephalic macrocephaly, coarse facial features, and joint contractures, with specific radiographic features like hook-shaped deformity of the vertebrae and abnormally shaped tubular bones in the hands.
Skeletal Dysplasias and Genetic Disorders: Key Points
- Skeletal dysplasias are heritable disorders characterized by abnormalities in cartilage and bone growth, leading to abnormal skeletal shape and size.
- Osteochondromas are cartilage-capped benign bone tumors that arise in the metaphysis of long bones, leading to bone shortening and bowing, and can cause pain or numbness from nerve compression.
- Most common locations for exostoses are the distal femur, proximal tibia, humerus, and proximal fibula, with the potential for malignant transformation into chondrosarcoma.
- Skeletal dysplasias can be diagnosed through radiographic features and genetic testing of EXT1 and EXT2, with a 50% chance of transmission to offspring and a 10-20% chance of spontaneous mutation.
- Mutations in EXT1, EXT2, and EXT3 genes result in the synthesis of truncated EXT proteins, affecting heparan sulfate synthesis and leading to abnormal bone growth and disruption of physeal growth.
- Skeletal dysplasias can cause joint pain, neurovascular compression, spinal deformities, and autism-like social problems, and may be more severe if the mutation is on the EXT1 gene.
- Diagnosis of genetic disorders involves genetic material examination, in-depth family history, and varied methods such as prenatal diagnosis through fetal development ultrasound or amniocentesis.
- Treatment for skeletal dysplasias includes surgical options like ostechondroma excision, gradual or acute bone lengthening, and corrective osteotomies, as well as gene therapy and supportive therapy.
- Genetic disorders can affect various stages of development and have diverse prognoses, with no known cures at present, requiring maintenance of quality of life and patient autonomy through physiotherapy, pain management, and supportive or alternative medicine programs.
- Common skeletal dysplasias include achondroplasia, osteogenesis imperfecta, thanatophoric dysplasia, campomelic dysplasia, and hypochondroplasia, each with distinct clinical and radiographic features.
- Achondroplasia is characterized by short stature, a relatively normal-sized trunk, large head, and rhizomelic shortening of the limbs, while osteogenesis imperfecta presents with short, thick, ribbonlike long bones and multiple fractures.
- Hurler syndrome, a mucopolysaccharidosis type IH, leads to dysplasia, scaphocephalic macrocephaly, coarse facial features, and joint contractures, with specific radiographic features like hook-shaped deformity of the vertebrae and abnormally shaped tubular bones in the hands.
Test your knowledge of skeletal dysplasias and genetic disorders with this quiz. Explore key points related to heritable disorders, diagnostic methods, genetic mutations, clinical features, and treatment options. Sharpen your understanding of conditions like achondroplasia, osteogenesis imperfecta, and Hurler syndrome.
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