This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetics, Subject name: Medicine
Absent radius is seen in all except 
Select and explain. 
A. Haltoram, B. Fanconi anaemia, C. Trisomy 13, D. Ectoderm dyplasia
D: Ectoderm dyplasia
Answer: D: Ectoderm dyplasia 
Explanation: Ectodermal dysplasia (ED) is not a single disorder but a group of genetic syndromes all deriving from abnormalities of the ectodermal structures:570 More than 150 different syndromes have been identified. Ectodermal dysplasias are described as "heritable conditions in which there are abnormalities of two or more ectodermal structures such as the hair, teeth, nails, sweat glands, salivary glands, cranial-facial structure, digits and other pas of the body. Absent radius is not seen in ectodermal dysplasia Ref Robbins 9/e pg 145