A. Myotonic dystrophy is an autosomal dominant trait.
B. Sickle cell anemia is an autosomal recessive trait.
C. Cystic fibrosis is a Mendelian disorder.
D. Failure of segregation of chromatids during cell division cycle results in the gain or loss of a chromosome(s) called aneuploidy.

Options

A. Only C is incorrect
B. All incorrect
C. Only C is incorrect
D. All are correct

Answer

To analyze the statements provided regarding genetic disorders and chromosomal abnormalities, we can break them down as follows:

### Step 1: Analyze Statement A
**Statement A:** Myotonic dystrophy is an autosomal dominant trait.
- Myotonic dystrophy is indeed classified as an autosomal dominant disorder. This means that only one copy of the mutated gene from an affected parent can cause the disorder in the offspring.

### Step 2: Analyze Statement B
**Statement B:** Sickle cell anemia is an autosomal recessive trait.
- Sickle cell anemia is correctly identified as an autosomal recessive disorder. This means that an individual must inherit two copies of the mutated gene (one from each parent) to express the disease.

### Step 3: Analyze Statement C
**Statement C:** Cystic fibrosis is a Mendelian disorder.
- Cystic fibrosis is also an autosomal recessive disorder and is considered a Mendelian disorder because it follows Mendel's laws of inheritance. It occurs due to mutations in the CFTR gene.

### Step 4: Analyze Statement D
**Statement D:** Failure of segregation of chromatids during cell division cycle results in the gain or loss of a chromosome(s) called aneuploidy.
- This statement is accurate. Aneuploidy occurs when there is an error in cell division, specifically during meiosis or mitosis, leading to an abnormal number of chromosomes in the daughter cells.

### Conclusion
- All statements A, B, C, and D are correct regarding their respective genetic conditions and chromosomal abnormalities.