The most common chromosomal defect is:
Correct Answer: Down’s
Description: Down’s syndrome is the most common of the chromosome disorders and a major cause of mental retardation.
Cytogenetic abnormality
Non disjunction (MC) = 95%
Translocation (robertsonian) = 4 %
Mosaicism = 1%
Increased maternal age is the main risk factor .
Translocation carriers carry high recurrence risk.
Clinical features: Cardiac → endocardial cushion defect (MC)
Hypotonia GIT → duodenal atresia, TEF, IHPS, Hirschprung
Mental retardation disease, annular pancreas
Short stature musculoskeletal system → atlantoaxial
Dislocation
Microcephaly/ brachycephaly Respiratory → recurrent aspiration pneumonia
Open AF Endocrine → primary gonadal defect,
Hypothyroidism
Oblique palpebral fissure Haematopoietic → increased ALL and AML
Bushfield spot . But AML has a better
Depressed nasal bridges prognosis than normal individuals
Low set ears CNS Alzheimer's in patients older than 40 years
Short neck
Simian crease, clinodactyly
Sandal gap between 1st and 2nd
Toes
Kennedy crease
Category:
Pathology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now