NEET-PG 2019 — Psychiatry

Q: Risk of genetic diseases in consanguineous marriage between first cousins?

4-8%. ***4-8%*** - The risk of genetic diseases in offspring from a **first-cousin consanguineous marriage** is generally estimated to be **two- to threefold higher than the baseline risk** in the general population. - While the general population risk for a serious birth defect or genetic disease is around 3-4%, this increased risk typically places the range for first cousins at **4-8%**. *1-2%* - This percentage represents a **lower risk than what is typically observed** with first-cousin consanguinity. - The baseline risk for genetic disease in the general population is usually around 3-4%, and consanguineous unions significantly increase this risk. *2-4%* - This represents approximately the **baseline population risk** without consanguinity, not the increased risk seen with first-cousin marriages. - Students may incorrectly assume that first-cousin marriage does not significantly elevate the baseline genetic disease risk. *8-10%* - While there is an increased risk, this range is generally considered **higher than the average estimated risk** for first-cousin consanguineous marriages, which is typically quoted at 4-8%. - This higher range might be seen in cases of **more distant consanguinity** or in populations with a **higher prevalence of specific recessive conditions**. *12-14%* - This magnitude of risk is usually associated with **closer degrees of consanguinity**, such as uncle-niece or half-sibling relationships, rather than first cousins. - The **coefficient of inbreeding** for first cousins is 1/16, which carries a lower risk than these closer relationships. [Practice more Psychiatry PYQs on OnCourse]

Q: What is the typical IQ range for males affected with Fragile X syndrome?

IQ range of 60-80. **IQ range of 60-80** - Males affected with **Fragile X syndrome** typically experience **moderate intellectual disability**, corresponding to an IQ range of 60-80. - This range indicates significant cognitive impairment, yet usually allows for some level of independent living and vocational skills with support. *IQ range of 20-40* - An IQ range of 20-40 represents **severe intellectual disability**, which is less common for the typical presentation of Fragile X syndrome in males. - While some individuals with Fragile X may fall into this range, it is not considered the most typical or average outcome. *IQ range of 50-70* - An IQ range of 50-70 represents **mild to moderate intellectual disability**, which overlaps with but is generally slightly lower than the most typical presentation. - While many males with Fragile X syndrome may score in this range, the typical range cited in literature extends slightly higher to 60-80. *IQ range of 80-100* - An IQ range of 80-100 is considered **borderline to low-average intelligence**, which is generally higher than the typical impact of Fragile X syndrome on male cognitive function. - This range is not indicative of the moderate intellectual disability characteristic of the syndrome. *Normal IQ range (90-110)* - A **normal IQ range (90-110)** is inconsistent with the diagnosis of Fragile X syndrome, which is a leading cause of inherited intellectual disability. - While females with Fragile X may have a wider range of IQs, including normal intelligence, males are typically more severely affected. [Practice more Psychiatry PYQs on OnCourse]

2 Previous Year Questions with Answers & Explanations

Questions

Risk of genetic diseases in consanguineous marriage between first cousins?

What is the typical IQ range for males affected with Fragile X syndrome?