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Infantile citrullinemia caused by citrin deficiency with increased dibasic amino acids
Efrat Ben-Shalom1, Keiko Kobayashi, Avraham Shaag
1The Metabolic Disease Unit, Faculty of Medicine, Shaare-Zedek Medical Center, Hebrew University, Jerusalem, Israel.
Insights
A novel mutation in the citrin gene (SLC25A13) caused prolonged jaundice and liver dysfunction in an infant. Treatment with formula normalized amino acid levels, suggesting a dietary link to this rare genetic disorder.
Area of Science:
- Biochemistry
- Genetics
- Pediatrics
Background:
- Infantile-onset liver disease presents diagnostic challenges.
- Prolonged icterus and hepatocellular dysfunction require thorough etiological investigation.
Observation:
- An infant exhibited elevated plasma and urinary citrulline and dibasic amino acids.
- Abnormal liver tests and amino acid levels normalized upon switching from breast milk to formula feeding.
Findings:
- A novel mutation, a 9.5-kb genomic duplication in the citrin gene (SLC25A13), was identified.
- This mutation led to the insertion of exon 15, causing infantile citrin deficiency.
- No mutations were found in the SLC7A2 gene, excluding a defect in the cationic amino acid transporter.
Implications:
- This case expands the known genetic spectrum of citrin deficiency.
- It highlights the importance of considering citrin deficiency in non-Asian infants with unexplained liver dysfunction.
- Dietary management may play a crucial role in managing this condition.
Abstract:
In an infant who suffered from prolonged icterus and hepatocellular dysfunction we detected an increase of citrulline and dibasic amino acids in plasma and urine. The amino acid levels along with all the abnormal liver tests normalized upon replacing breast-milk by formula feeding; there was no relapse after human milk was tentatively reintroduced. A novel mutation, a approximately 9.5-kb genomic duplication, was identified in the citrin gene (SLC25A13) resulting in the insertion of exon 15. No mutation was detected in the CAT2A specific exon of the SLC7A2 gene which encodes for the liver transporter of cationic amino acids. This is the first report of infantile citrin deficiency in non-Asian patients.