Adrenoleukodystrophy (ALD)is a fatal disease that results from the inability of liver cells to transport very long chain fatty acids (VLCFAs)across the peroxisomal membrane.It is diagnosed by the presence of high levels of VLFCAs in the blood.The disease results in destruction of brain myelin leading to progressive cognitive impairment,coma,and death by the age of 14.ALD is an X-linked recessive condition,and there has never been a case of ALD described in girls.You have just started your internship at the Mayo clinic and a 10-year-old girl comes in who is in a coma and having seizures.Blood tests show she has extremely elevated levels of long-chain fatty acids.This looks like ALD,but a girl has never been afflicted.When you go to your supervisor to give your diagnosis,which of the following hypotheses do you present to support it?
A)Both her mother and father are recessive carriers of ALD.
B)Most of the Barr bodies in the affected girl's liver have a normal peroxisome gene.
C)Her mother is a carrier for ALD.
D)She has Turner syndrome.
E)Her mother is a carrier,and either the affected girl has only genetically normal Barr bodies in her liver or she has Turner syndromE.

Question

Quizplus · Accepted Answer

ALD is an X-linked recessive disease, meaning it is carried on the X chromosome. As females have two X chromosomes, they are usually only carriers of the disease, as the healthy copy of the X chromosome can compensate for the defective one. However, in rare cases, females can exhibit symptoms of ALD if they have two copies of the defective X chromosome or if they have Turner syndrome, which results in only having one X chromosome. Therefore, the best choice is E, as it considers the possibility of the affected girl either having only genetically normal Barr bodies in her liver or having Turner syndrome, while also acknowledging that her mother is a carrier of the disease.

Adrenoleukodystrophy (ALD)is a Fatal Disease That Results from the Inability