We use cookies to improve your experience and understand how Examtube is used. You can accept analytics cookies or continue with essential cookies only.
Privacy policy5 public questions tagged with this topic.
Edward’s syndrome is caused by trisomy of chromosome 18, leading to severe developmental issues.
Ref: NCERT Class 12 Biology Chapter 4: Principles of Inheritance and Variation Chromosomal Theory Linkage Recombination Gene Mapping
Down’s syndrome is caused by an extra copy of chromosome 21, not the Y chromosome.
Ref: NCERT Class 12 Biology Chapter 4: Principles of Inheritance and Variation Polygenic Inheritance Pleiotropy and Quantitative Inheritance
Down’s syndrome is caused by trisomy of chromosome 21, leading to developmental and cognitive impairments.
Ref: NCERT Class 12 Biology Chapter 4: Principles of Inheritance and Variation Polygenic Inheritance Pleiotropy and Quantitative Inheritance
Klinefelter syndrome sex chromosome aneuploidy 47,XXY most common among newborn males about 1 in 660 births, often underdiagnosed until adolescence adulthood due subtle phenotype. Presentation includes tall stature with long legs disproportionate, small firm testes under 4 ml volume, hypergonadotropic hypogonadism reduced testosterone, gynecomastia breast enlargement, azoospermia infertility due seminiferous tubule dysgenesis, variable language learning difficulties but intelligence usually normal range. Supernumerary X undergoes inactivation forming Barr body partially compensating dosage, pe
Ref: Lewis, Human Genetics, 12th ed., Chapter 9: Klinefelter 47,XXY Karyotype and Clinical Features
Turner syndrome monosomy X karyotype 45,X found in about 1 in 2500 female births though 99 percent concepti abort spontaneously, indicating strong selection. Phenotype includes short stature below third centile under 150 cm, primary amenorrhea due to streak ovaries and infertility hypergonadotropic, webbed neck with low hairline, broad chest widely spaced nipples, lymphedema newborn feet hands, coarctation aorta bicuspid valve, renal anomalies horseshoe kidney, normal intelligence usually with specific visuospatial learning difficulties. Single X random loss paternal or maternal sex chromosome
Ref: Pierce, Genetics: A Conceptual Approach, 7th ed., Chapter 8: Turner 45,X Karyotype Phenotype
Add our app to your home screen for a better experience.
