Question

Which one of the following is an autosomal dominant syndrome in its inheritance?

• A. Gilbert’s syndrome
• B. Crigler-Naijar syndrome Type-I
• C. Dubin-Johnson syndrome
• D. Rotor syndrome

Answer 1

The Correct Option is A

To determine which of the given syndromes is inherited in an autosomal dominant manner, we need to understand what autosomal dominant inheritance means and the genetic basis of each option provided.

An autosomal dominant disorder is one in which a single altered copy of the gene in each cell is sufficient to cause the disorder. This means that the condition can occur in all generations and affects both males and females equally, as the gene is located on one of the non-sex chromosomes (autosomes).

1. Gilbert's Syndrome: This is primarily characterized by elevated levels of bilirubin in the blood due to reduced activity of the enzyme UDP-glucuronosyltransferase. It is generally inherited as an autosomal dominant trait, which means that only one abnormal gene from one parent can cause the disorder.
2. Crigler-Najjar Syndrome Type I: This condition is characterized by a complete absence of the enzyme needed to attach sugars to bilirubin, making it difficult for those with the disorder to clear bilirubin from the blood. It is inherited in an autosomal recessive manner, requiring two copies of the faulty gene, one from each parent.
3. Dubin-Johnson Syndrome: This is a rare, benign, hereditary cause of chronic conjugated hyperbilirubinemia which is inherited in an autosomal recessive pattern.
4. Rotor Syndrome: Similar to Dubin-Johnson syndrome, Rotor syndrome is an autosomal recessive condition leading to a clinically benign increase in conjugated bilirubin.

From the options above, Gilbert’s syndrome is the only one that is commonly inherited in an autosomal dominant manner. The other syndromes listed are inherited in an autosomal recessive manner, meaning that both parents must carry and pass on the allele for the disorder for it to be expressed in the offspring.

Therefore, the correct answer is Gilbert’s syndrome.