• Test code: 06197
  • Turnaround time:
    10–21 calendar days (14 days on average)
  • Preferred specimen:
    3mL whole blood in a purple-top EDTA tube (K2EDTA or K3EDTA)
  • Alternate specimens:
    Saliva, assisted saliva, buccal swab and gDNA
  • Sample requirements
  • Request a sample kit

Invitae Multiple Acyl-CoA Dehydrogenase (MAD) Deficiency Panel

Test description

The Invitae Multiple Acyl-CoA Dehydrogenase Deficiency Panel analyzes up to 6 genes that are associated with multiple acyl-CoA dehydrogenase (MAD) deficiency. This test is useful for the diagnosis of patients in whom MAD deficiency is suspected due to clinical symptoms, abnormal newborn screening (NBS) results, or biochemical findings. This test may help distinguish MAD deficiency from other fatty acid oxidation disorders (FAODs) and riboflavin transporter deficiencies, which can have overlapping clinical and biochemical presentations. Knowing the underlying molecular cause of a patient’s MAD deficiency may also help inform management because some mutations are known to be responsive to riboflavin therapy.

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Primary panel (3 genes)
Add-on Riboflavin Transporter Deficiency Genes (3 genes)

Patients with riboflavin transporter deficiency can have elevations on plasma acylcarnitine analysis similar to patients with MAD deficiency. Given the biochemical overlap between riboflavin transporter deficiency and MAD deficiency, analyzing these genes may be appropriate. These genes can be included at no additional charge.


  • multiple acyl-CoA dehydrogenase (MAD) deficiency (MADD) – also known as glutaric acidemia type 2 (GA2)
    • neonatal multiple acyl-CoA dehydrogenase deficiency with congenital anomalies
    • neonatal multiple acyl-CoA dehydrogenase deficiency without congenital anomalies
    • late-onset multiple acyl-CoA dehydrogenase deficiency
  • ethylmalonic-adipic aciduria

MAD deficiency is an in inborn error of metabolism that interferes with the body’s ability to break down proteins and fats to produce energy. Incomplete breakdown of proteins and fats can cause blood and tissues to become acidotic, producing metabolic acidosis.

MAD deficiency is a fully penetrant disorder. Patients with MAD deficiency show a wide range of symptoms and severity. Patients with little or no enzyme activity typically have the severe neonatal presentation while patients with higher residual enzyme activity have the mild, late-onset form. Type I, the most severe form, can present in the neonatal period with life-threatening acidosis, vomiting, and seizures. Patients with the severe form may have physical abnormalities including facial dysmorphism, brain malformations, hypoglycemia, hypotonia, hepatomegaly, kidney cysts, and genital abnormalities. There may also be hepatomegaly, dilated cardiomyopathy, and sweaty-feet odor. Type I is typically fatal. Type II presents with similar symptoms but no physical abnormalities, and type III presents later, with intermittent episodes of hypoglycemia, metabolic acidosis, muscle weakness, and exercise-induced muscle pain. Some patients with the late-onset form remain asymptomatic despite the presence of biochemical abnormalities. Riboflavin has been shown to be an effective treatment for patients with late-onset MAD deficiency.

Patients with MAD deficiency typically show elevations of C4 and C5 in newborn screening. Upon plasma acylcarnitine analysis, patients can have elevations of C4, C5, and many other acylcarnitine species, which can lead to secondary carnitine deficiency. Severely affected patients can have elevations of 2-hydroxyglutaric acid, glutaric acid, ethylmalonic acid, and dicarboxylic aciduria during urine organic acids testing; patients with a milder form may only have elevations of ethylmalonic acid, adipic acid, ketones, and dicarboxylic acids. Isobutyrylglycine, isovalerylglycine, hexanoylglycine, and suberylglycine elevations may also be detected in urine. The organic aciduria can be normal in mildly affected patients, only manifest during times of metabolic stress.

For patients with a biochemical diagnosis of MAD deficiency (characteristic plasma acylcarnitines and urine organic acids, with or without enzyme analysis), >99% are expected to have pathogenic variants in ETFA, ETFB, or ETFDH. 93% of patients with late-onset disease carry pathogenic variants in ETFDH, 5% carry variants in ETFA, and 2% have variants in ETFB.

MAD deficiency is inherited in an autosomal recessive manner.

MAD deficiency is a very rare disorder with prevalence estimated at 1 in 200,000. There is great variation between countries and ethnicities. Incidence among the southern Chinese is approximately 1 in 22,500.

Testing for MAD deficiency should be considered in newborns and infants with:

  • metabolic acidosis and non-ketotic hypoglycemia
  • elevated blood acylcarnitines (increased C4-C18 species in patients with severely low carnitine)
  • an abnormal urine organic acid profile (various combinations of increased dicarboxylic acids, glutaric acid, ethylmalonic acid, 2-hydroxyglutarate, and glycine conjugates)
  • abnormal fibroblast fatty acid oxidation studies
  • congenital anomalies (facial dysmorphism, rocker bottom feet, abnormal external genitalia)
  • cardiomyopathy
  • hepatomegaly
  • dysplastic kidneys with cysts
    in children with:
  • vomiting
  • lethargy
  • hepatomegaly
  • seizures
    and in older children and adults with:
  • muscle weakness
  • exercise-induced muscle pain
  • lipid storage myopathy

Assay and technical information

Invitae is a College of American Pathologists (CAP)-accredited and Clinical Laboratory Improvement Amendments (CLIA)-certified clinical diagnostic laboratory performing full-gene sequencing and deletion/duplication analysis using next-generation sequencing technology (NGS).

Our sequence analysis covers clinically important regions of each gene, including coding exons and 10 to 20 base pairs of adjacent intronic sequence on either side of the coding exons in the transcript listed below. In addition, the analysis covers the select non-coding variants specifically defined in the table below. Any variants that fall outside these regions are not analyzed. Any limitations in the analysis of these genes will be listed on the report. Contact client services with any questions.

Based on validation study results, this assay achieves >99% analytical sensitivity and specificity for single nucleotide variants, insertions and deletions <15bp in length, and exon-level deletions and duplications. Invitae's methods also detect insertions and deletions larger than 15bp but smaller than a full exon but sensitivity for these may be marginally reduced. Invitae’s deletion/duplication analysis determines copy number at a single exon resolution at virtually all targeted exons. However, in rare situations, single-exon copy number events may not be analyzed due to inherent sequence properties or isolated reduction in data quality. Certain types of variants, such as structural rearrangements (e.g. inversions, gene conversion events, translocations, etc.) or variants embedded in sequence with complex architecture (e.g. short tandem repeats or segmental duplications), may not be detected. Additionally, it may not be possible to fully resolve certain details about variants, such as mosaicism, phasing, or mapping ambiguity. Unless explicitly guaranteed, sequence changes in the promoter, non-coding exons, and other non-coding regions are not covered by this assay. Please consult the test definition on our website for details regarding regions or types of variants that are covered or excluded for this test. This report reflects the analysis of an extracted genomic DNA sample. In very rare cases, (circulating hematolymphoid neoplasm, bone marrow transplant, recent blood transfusion) the analyzed DNA may not represent the patient's constitutional genome.

Gene Transcript reference Sequencing analysis Deletion/Duplication analysis
ETFA NM_000126.3
ETFB NM_001985.2
ETFDH NM_004453.3
SLC52A1 NM_017986.3
SLC52A2 NM_024531.4
SLC52A3 NM_033409.3