Amniocentesis Indications: Identifying the Exception
Amniocentesis is a prenatal diagnostic procedure used primarily to detect chromosomal abnormalities and certain genetic disorders in the fetus. It involves collecting a sample of amniotic fluid surrounding the baby.
Analyzing Amniocentesis Indications
The procedure is typically recommended based on specific risk factors. Let's analyze the given circumstances:
- Mother aged 35 years or more: Advanced maternal age (specifically starting around 35) is a well-known risk factor for fetal chromosomal aneuploidies, such as Down syndrome (Trisomy 21). Therefore, amniocentesis is commonly offered. Using LaTeX notation, this is represented as $age_{mother} \geq 35$.
- Previous child with chromosomal anomalies: A history of having a child with Down syndrome or other chromosomal disorders significantly increases the risk of recurrence. Amniocentesis is highly indicated in subsequent pregnancies.
- Parents with known chromosomal translocation: Parents who are carriers of chromosomal translocations have an increased risk of conceiving a fetus with an unbalanced chromosomal number. Genetic counseling usually precedes amniocentesis in these cases.
- Father aged 50 year or more: While advanced paternal age has been linked to a slightly increased risk of certain genetic conditions (like achondroplasia or some autosomal dominant disorders), it is not considered a primary or strong independent indication for amniocentesis specifically for common chromosomal aneuploidies compared to advanced maternal age or previous affected children. The risk is generally lower and less established for common trisomies. Using LaTeX notation, this is represented as $age_{father} \geq 50$.
Conclusion on Amniocentesis Exception
Based on standard clinical guidelines for prenatal screening for common chromosomal abnormalities, advanced paternal age alone (like a father aged 50 or more) is the least likely reason to routinely recommend amniocentesis compared to the other factors listed. Therefore, this is the circumstance where amniocentesis is typically NOT called for as a primary indication among the choices provided.
Important Questions from Genetic Disorders & Public Health
- Which one of the following conditions is NOT inborn error of metabolism?
- Consider the following pairs of genetic diseases that show Mendelian inheritance. Each of the following pairs represents a genetic disease and it has been matched with a type of inheritance :How many of the pairs given above are correctly matched?
1 Cystic fibrosis Autosomal recessive 2 Huntington's chorea Autosomal dominant 3 Marfan's syndrome Recessive sex-linked Consider the following statements :
Statement I:
Signs of thalassemia major usually develop after 6 months of age.
Statement II:
This is the time when haemoglobin synthesis switches from haemo-globin F to haemoglobin A.
Which one of the following is correct in respect of the above statements?
- Cystic fibrosis involves which of the following organs?
1. Lungs
2. Liver
3. Pancreas
4. Kidney
Select the correct answer using the code given below. - Which of the following statements are correct in respect of haemophilia?
1. It is hereditary bleeding disorder.
2. It has a higher incidence among Asians.
3. It affects females occasionally and mildly.
Select the correct answer using the code given below.
