Ans. D: 47, XXY Genetic analysis reveals the karyotype of klinefelter's syndrome to be 47 XXY Klinefelter syndrome/ 46 or 47, XXY/ XXY syndrome It is a condition with an extra X chromosome. Because of the extra chromosome, individuals with the condition are usually referred to as "XXY Males", or "47, XXY Males" Klinefelter syndrome is the most common sex chromosome disorder in males and the second most common condition caused by the presence of extra chromosomes. The condition exists in roughly 1 out of every 500-650 males but many of these people may not show symptoms. Principal effects include hypogonadism and reduced feility. Turner syndrome/Ullrich-Turner syndrome/Gonadal dysgenesis It encompasses several conditions in human females, of which monosomy X (absence of an entire sex chromosome, the Barr body) is most common. It is a chromosomal abnormality in which all or pa of one of the sex chromosomes is absent (unaffected humans have 46 chromosomes, of which two are sex chromosomes). Normal females have two X chromosomes, but in Turner syndrome, one of those sex chromosomes is missing or has other abnormalities. In some cases, the chromosome is missing in some cells but not others, a condition referred to as mosaicism or 'Turner mosaicism'. Occurring in 1 in 2000 -1 in 5000 phenotypic females. There are characteristic physical abnormalities, such as Sho stature, Broad chest, - Low hairline, - Low-set ears, and - Webbed necks. Girls with Turner syndrome typically experience gonadal dysfunction (non-working ovaries), which results in amenorrhea (absence of menstrual cycle) and sterility. Concurrent health concerns are also frequently present, including congenital hea disease, hypothyroidism, diabetes, vision problems, hearing concerns, and many autoimmune diseases. Finally, a specific pattern of cognitive deficits is often observed, with paicular difficulties in visuospatial, mathematical, and memory areas Down syndrome/trisomy 21 Down syndrome is a chromosomal condition characterized by the presence of an extra copy of genetic material on the 21st chromosome, either in whole (trisomy 21) or pa (such as due to translocations). The incidence of Down syndrome is estimated at 1 per 733 bihs It is statistically more common with older parents due to increased mutagenic exposures upon some older parents' reproductive cells. Down syndrome is associated with some impairment of cognitive ability and physical growth, and a paicular set of facial characteristics. Individuals with Down syndrome tend to have a lower-than-average cognitive ability, often ranging from mild to moderate disabilities. The average IQ of children with Down syndrome is around 50, compared to normal children with an IQ of 100. A small number have a severe to high degree of intellectual disability Individuals with Down syndrome may have some or all of the following physical characteristics: - Microgenia (an abnormally small chin), - An unusually round face, macroglossia (protruding or oversized tongue), - An almond shape to the eyes caused by an epicanthic fold of the eyelid, Upslanting palpebral fissures (the separation between the upper and lower eyelids), Shoer limbs, - A single transverse palmar crease (a single instead of a double crease across one or both palms), - Poor muscle tone, and - A larger than normal space between the big and second toes. Health concerns for individuals with Down syndrome include a higher risk for congenital hea defects, gastroesophageal reflux disease, recurrent ear infections that may lead to hearing loss, obstructive sleep apnea, thyroid dysfunctions, and obesity.