Topic Name

Message

If ARUP Consult does not answer your test selection and interpretation questions, or if you would like to suggest ways to improve content or usability, please send a message to the Consult editorial staff.

Please do not include any patient-specific or personal health information (PHI) in your message.

Email Address

An email address is not required, but providing one allows the ARUP Consult editorial staff to respond directly. ARUP will only use your email address to respond to your feedback. See the ARUP privacy policy for more information regarding email use.

CAPTCHA

What code is in the image?

Enter the characters shown in the image.

This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

Very Long-Chain and Branched-Chain Fatty Acids Profile

2004250

Very Long-Chain and Branched-Chain Fatty Acids Profile 2004250

Method

Liquid Chromatography-Tandem Mass Spectrometry

Biochemical test to measure concentration of very long-chain fatty acids (VLCFAs) C22-C26, pristanic acid, and phytanic acid
Initial test to screen for disorders of peroxisomal biogenesis and/or function, including X-ALD and Zellweger syndrome
Confirmatory test for abnormal newborn screening suggestive of X-ALD

If a familial sequence variant has been previously identified, targeted sequencing for that variant may be appropriate; refer to the Laboratory Test Directory for additional information.

X-linked adrenoleukodystrophy (X-ALD) is a rare X-linked metabolic disorder caused by variants in the ABCD1 gene that cause a deficiency in adrenoleukodystrophy protein (ALDP) and subsequent accumulation of very long-chain fatty acids (VLCFAs). VLCFA accumulation occurs in plasma and all tissue types, but primarily affects the adrenal cortex and white matter of the brain and spinal cord, resulting in a range of clinical outcomes.

Adrenal insufficiency may be the initial presentation of X-ALD, and 21-hydroxylase antibody testing may confirm or exclude an autoimmune etiology. In X-ALD, 21-hydroxylase antibody testing results will be normal; therefore, males with adrenal insufficiency and normal 21-hydroxylase antibody testing should be tested for X-ALD (VLCFA profile).

For additional information on the testing strategy for X-ALD, refer to the ARUP Consult X-Linked Adrenoleukodystrophy topic.

Disease Overview

Incidence

1/14,700 live births

Penetrance

Neurologic symptoms are present in nearly 100% of males with the disease by adulthood.

Inheritance

X-linked

Test Interpretation

Biochemical testing (VLCFAs and BCFAs)

Males: Elevated VLCFAs
Females: Elevated VLCFAs in approximately 85% of heterozygous carriers

References

30732635

Huffnagel IC, Dijkgraaf MGW, Janssens GE, et al. Disease progression in women with X-linked adrenoleukodystrophy is slow. Orphanet J Rare Dis. 2019;14(1):30.

25999754

Wiesinger C, Eichler FS, Berger J. The genetic landscape of X-linked adrenoleukodystrophy: inheritance, mutations, modifier genes, and diagnosis. Appl Clin Genet. 2015;8:109-121.

Feedback