OBJECTIVETo identify potential mutation of SLC22A5 gene in a 5-month-old boy affected with primary carnitine deficiency and provide genetic counseling and prenatal diagnosis for the members of his family.

METHODSDNA was extracted from peripheral blood samples derived from the proband, his parents and elder sister, as well as amniotic fluid from his pregnant mother. All of the 10 exons of the SLC22A5 gene were amplified by PCR and subjected to Sanger sequencing. The amniotic fluid sample was also subjected to G-banded karyotyping and multiplex ligation-dependent probe amplification (MLPA).

RESULTSA homozygous mutation c.760C>T (p.R254X) of the SLC22A5 gene was detected in the proband. Heterozygous mutation c.760C>T (p.R254X) was also found in other family members including the fetus. The karyotyping and chromosomal microdeletion testing for the amniotic fluid sample were both normal.

CONCLUSIONThe newly identified homozygous nonsense c.760C>T (p.R254X) mutation of the SLC22A5 gene probably underlies the primary carnitine deficiency of the proband. Genetic counseling and prenatal diagnosis have been provided for this family.