CARNITINE PALMITOYL TRANSFERASE 1A DEFICIENCY: HOW TO SCREEN AND TREAT?  

Presented By:

Risto Lapatto, MD, PhD, Children’s Hospital, University of Helsinki,
Helsinki, Finland

Jetta Tuokkola, RD, PhD, Children’s Hospital, University of Helsinki,
Helsinki, Finland

Corresponding author contact information: risto.lapatto@hus.fi
Phone+358504286413

Background: Carnitine palmitoyl transferase 1A (CPT1A) deficiency does exist in Finland. Patients with CPT1A deficiency have died of decompensation episodes triggered by infections. Hence it is a significant clinical problem.
In order to decide whether it should be included in the national newborn screening program (NBS), we wanted to ensure that there is a good screening test available and that we can provide clinically effective treatment. Therefore, we studied global screening data and data of our patients. Prior to the NBS, CPT1A deficiency diagnosis was usually made after a decompensation episode of the patient or one of his relatives.

Methods: Finnish and global screening data from Region4 project were used to determine best parameters and cut-offs. This was achieved by comparing values of known cases to those suffering from other metabolic diseases and to those of healthy controls. In addition, based on experience elsewhere, we decided to treat one child diagnosed at the age of four immediately after diagnosis with a diet with normal fat content, but with frequent meals and uncooked corn starch in the evening. Earlier we have used a low-fat diet, but positive results encouraged us to transfer four patients treated first with a low-fat diet to a free diet. The dietary follow-up included assessment of food diaries or dietary review and recommendations about the diet, fasting tolerance and dietary supplements. Patients have been followed up in a metabolic clinic by a physician and a dietitian at least annually, and clinical assessment has been complemented by laboratory tests. 

Results: Dried blood spot samples are used in the Finnish NBS, and acylcarnitine analysis is performed for detection of several fatty acid oxidation and carnitine metabolism disorders. We found that both C0, C0/(C16+C18) and

C0/C16 were good at separating CPT1A deficiency patients from other patients and controls. C0/C16 was very sensitive and had a good specificity with cut-offat around 50. In rare cases when C16 is extremely low (<0.5) using C0 with a cut-off at around 100 is better.

All patients have grown and developed normally. There have been no complications related to CPT1A deficiency. Laboratory values show normal blood count, liver and renal function, muscle enzymes, bone markers etc. Acylcarnitine profile remains abnormal with elevated C0 and low long-chain acylcarnitines.

We have occasionally observed low vitamin levels if patients have omitted their recommended supplements. The one child who has never been on a low-fat diet has followed the recommendations and taken his supplements, and thus has not had any vitamin deficiencies. The other patients have liberalized their diets variably. Some still follow a relatively low-fat diet whereas others have adopted a relatively high-fat diet.

Conclusions: CPT1A is a significant clinical problem in Finland. There is a good laboratory test available for the newborn screening. The treatment is effective, safe and easy to administer. Therefore CPT1A deficiency was included in the expended newborn screening program in Finland. Based on our experience, it seems safe to treat patients at least from four years onwards with a diet with no reduction in the fat content. Fasting tolerance is nevertheless reduced and patients require an emergency regime for inter-current illness. Dietary follow-up is recommended to ensure a balanced diet.