CPT1 Deficiency

Other Names

Carnitine palmitoyl transferase deficiency, type 1A (CPT 1)

Carnitine palmitoyl transferase 1 deficiency


CPT 1 liver

Diagnosis Coding

E71.314, muscle carnitine palmitoyltransferase deficiency

Disorder Category

A fatty acid oxidation disorder



Elevated C0 and C0/(C16+C18) ration

Tested By

Tandem mass spectrometry (MS/MS); sensitivity=100%; specificity=N/A% [Schulze: 2003]


Carnitine palmitoyl transferase 1A (CPT1) is a mitochondrial enzyme involved in the conjugation of fatty acids to carnitine for subsequent transfer inside mitochondria through the action of a translocase. Mutations in the CPT1A gene cause CPT1. Deficiency of CPT1 results in impaired energy production, usually manifest during periods of prolonged fasting and/or increased energy demands (fever, stress), resulting in rapid onset of hypoglycemic crises. CPT1A is predominantly expressed in the liver and the muscle and the heart are not primarily affected in this condition.


CPT 1 is rare [Schulze: 2003], with fewer than 40 known cases. [CPT1 Deficiency (GeneReviews)]


Autosomal recessive

Prenatal Testing

DNA testing possible by amniocentesis or chorionic villus sampling (CVS) if both disease causing mutations of an affected family member have been identified.

Other Testing

Genetic testing is possible for at-risk family members if both disease causing mutations of an affected family member have been identified.

Clinical Characteristics

With treatment, episodes of hypoglycemia, and consequent neurologic injury, may be avoided. Without treatment, injury from hypoglycemic episodes may lead to developmental delay, seizures, coma, and death. Acute fatty liver of pregnancy may occur in a heterozygous mother of a homozygous fetus.

Initial signs/symptoms typically begin suddenly in association with an illness between eight and eighteen months of life and may be life-threatening. They usually include:
  • poor appetite,
  • vomiting,
  • lethargy,
  • lab findings:
    • hyperammonemia,
    • elevated transaminases,
    • metabolic acidosis, and
    • hypoglycemia.

Follow-up Testing after Positive Screen

Quantitative plasma acylcarnitine profile, enzyme activity assay in cultured fibroblasts, CPT1A gene sequencing. The increased C0/(C16+C18) ratio is better detected from the dried blood spot collected for newborn screening. In plasma, C0 can be only mildly increased with low levels of C16 and C18.

Primary Care Management

Upon Notification of the + Screen

If the Diagnosis is Confirmed

  • Educate the family regarding signs, symptoms, and the need to avoid fasting and to seek urgent care when the infant becomes ill (see CPT1 Deficiency - Information for Parents (STAR-G) for additional information);
  • Provide a letter and, when old enough, a MedicAlert bracelet indicating the risk for hypoglycemia and need for urgent treatment with IV glucose when illness or stress lead to symptoms;
  • Frequent, low fat, and high carbohydrate meals and snacks and, for infants, cornstarch feedings at night as a slow-release carbohydrate source;
  • Medium Chain Triglyceride (MCT) oil supplements may be indicated for some children;
  • For those identified after irreversible consequences, assist in management, particularly with developmental and educational interventions.

Specialty Care Collaboration

Initial consultation and ongoing collaboration if the child is affected. A dietician may work with the family to devise an optimal approach to dietary management. Genetic counseling for the family.


Information & Support

For Professionals

ACT Sheet for CPT1 Deficiency (ACMG) (PDF Document 344 KB)
Contains short-term recommendations for clinical follow-up of the newborn who has screened positive; American College of Medical Genetics.

Newborn Screening ACT Sheets & Confirmatory Algorithms (ACMG)
ACTion (ACT) Sheets and algorithms for responding to positive newborn screening test results, membership required; American College of Medical Genetics.

CPT1 Deficiency (GeneReviews)
Detailed information addressing clinical characteristics, diagnosis/testing, management, genetic counseling, and molecular pathogenesis; from the University of Washington and the National Library of Medicine.

Resources for CPT1 Deficiency (Disease InfoSearch)
Compilation of information, articles, research, case studies, and genetics links; from Genetic Alliance.

For Parents and Patients

CPT1 Deficiency - Information for Parents (STAR-G)
A fact sheet, written by a genetic counselor and reviewed by metabolic and genetic specialists, for families who have received an initial diagnosis of this newborn disorder; Screening, Technology and Research in Genetics.

Carnitine palmitoyltransferase I deficiency (MedlinePlus)
Information for families that includes description, frequency, causes, inheritance, other names, and additional resources; from the National Library of Medicine.

United Mitochondrial Disease Foundation
The United Mitochondrial Disease Foundation site provides parents and providers with information over 40 mitochondrial diseases; definitions of medical terms; professional articles; chapter links; newsletters; event information; and links to other sites.

Fatty Oxidation Disorders (FOD) Family Support Group
Information for families about fatty acid oxidation disorders, support groups, coping, finances, and links to other sites.

Services for Patients & Families in Nevada (NV)

Genetics clinic services throughout the US can be found through the Genetics Clinic Services Search Engine (ACMG).

For services not listed above, browse our Services categories or search our database.

* number of provider listings may vary by how states categorize services, whether providers are listed by organization or individual, how services are organized in the state, and other factors; Nationwide (NW) providers are generally limited to web-based services, provider locator services, and organizations that serve children from across the nation.

Helpful Articles

PubMed search for CPT1 deficiency, last 15 years.

Longo N, Amat di San Filippo C, Pasquali M.
Disorders of carnitine transport and the carnitine cycle.
Am J Med Genet C Semin Med Genet. 2006;142C(2):77-85. PubMed abstract / Full Text

Authors & Reviewers

Initial publication: March 2007; last update/revision: June 2012
Current Authors and Reviewers:
Author: Nicola Longo, MD, Ph.D.
Reviewer: Kimberly Hart, MS, LCGC

Page Bibliography

Schulze A, Lindner M, Kohlmuller D, Olgemoller K, Mayatepek E, Hoffmann GF.
Expanded newborn screening for inborn errors of metabolism by electrospray ionization-tandem mass spectrometry: results, outcome, and implications.
Pediatrics. 2003;111(6 Pt 1):1399-406. PubMed abstract