X-linked adrenoleukodystrophy.

[adrenomyeloneuropathy]

X-linked adrenoleukodystrophy (X-ALD ) is caused by a defect in the gene ABCD 1 , which maps to Xq 28 and codes for a peroxisomal membrane protein that is a member of the ATP-binding cassette transporter superfamily . X-ALD is panethnic and affects approximately 1 :20 ,000 males . Phenotypes include the rapidly progressive childhood , adolescent , and adult cerebral forms ; adrenomyeloneuropathy , which presents as slowly progressive paraparesis in adults ; and Addison disease without neurologic manifestations . These phenotypes are frequently misdiagnosed , respectively , as attention -deficit hyperactivity disorder (ADHD ), multiple sclerosis , or idiopathic Addison disease . Approximately 50 % of female carriers develop a spastic paraparesis secondary to myelopathic changes similar to adrenomyeloneuropathy . Assays of very long chain fatty acids in plasma , cultured chorion villus cells and amniocytes , and mutation analysis permit presymptomatic and prenatal diagnosis , as well as carrier identification . The timely use of these assays is essential for genetic counseling and therapy . Early diagnosis and treatment can prevent overt Addison disease , and significantly reduce the frequency of the severe childhood cerebral phenotype . A promising new method for mass newborn screening has been developed , the implementation of which will have a profound effect on the diagnosis and therapy of X-ALD .

Diseases
Validation

Diseases presenting "spastic paraparesis" symptom

adrenomyeloneuropathy

alexander disease

gm1 gangliosidosis

krabbe disease

phenylketonuria

x-linked adrenoleukodystrophy

This symptom has already been validated