The following statements about Fanconi’s anaemia are true except-a) Progressive pancytopeniab) Simultanagnosiac) Visual object agnosiad) Increased chromosomal fragilitye) Associated skeltal abnormalities involving thumb and radius

**Core Concept**
Fanconi's anaemia is a rare genetic disorder characterized by congenital abnormalities, bone marrow failure, and an increased risk of malignancies. It is a rare autosomal recessive disorder caused by mutations in the FANCA, FANCC, FANCD1 (BRCA2), FANCD2, FANCE, FANCI, FANCJ (BRIP1), FANCL, FANCM, FANCO (PALB2), FANCN (RAPD), FANCO (PROAP), or FANCP genes. These genes are involved in the repair of interstrand DNA crosslinks.

**Why the Correct Answer is Right**
The correct answer is not option B, as simultanagnosia is a visual field defect characterized by the inability to perceive objects or parts of objects when they are presented in a visual field that is partially occluded. Fanconi's anaemia is not typically associated with simultanagnosia. Option B is incorrect because simultanagnosia is more commonly seen in patients with bilateral occipital lobe lesions, such as those caused by herpes simplex encephalitis or traumatic brain injury.

**Why Each Wrong Option is Incorrect**
**Option A:** Progressive pancytopenia is a true statement about Fanconi's anaemia, as patients often experience bone marrow failure leading to decreased production of blood cells.

**Option C:** Visual object agnosia is not a characteristic of Fanconi's anaemia, which primarily affects the hematopoietic system.

**Option D:** Increased chromosomal fragility and associated skeletal abnormalities involving the thumb and radius are true statements about Fanconi's anaemia.

**Clinical Pearl / High-Yield Fact**
Fanconi's anaemia is associated with an increased risk of malignancies, particularly acute myeloid leukemia and squamous cell carcinoma of the head and neck.

**Correct Answer: D. Increased chromosomal fragility and associated skeletal abnormalities involving the thumb and radius**