Molecular spectrum of SLC22A5 (OCTN2) gene mutations detected in 143 subjects evaluated for systemic carnitine deficiency.
Systemic primary carnitine deficiency (CDSP) is caused by recessive mutations in the SLC22A5 (OCTN2) gene encoding the plasmalemmal carnitine transporter and characterized by hypoketotic hypoglycemia, and skeletal and cardiac myopathy. The entire coding regions of the OCTN2 gene were sequenced in 143 unrelated subjects suspected of having CDSP. In 70 unrelated infants evaluated because of abnormal newborn screening (NBS) results, 48 were found to have at least 1 mutation/unclassified missense variant. Twenty-eight of 33 mothers whose infants had abnormal NBS results were found to carry at least 1 mutation/unclassified missense variant, including 11 asymptomatic mothers who had 2 mutations. Therefore, sequencing of the OCTN2 gene is recommended for infants with abnormal NBS results and for their mothers. Conversely, 52 unrelated subjects were tested due to clinical indications other than abnormal NBS and only 14 of them were found to have at least one mutation/unclassified variant. Custom designed oligonucleotide array CGH analysis revealed a heterozygous approximately 1.6 Mb deletion encompassing the entire OCTN2 gene in one subject who was apparently homozygous for the c.680G>A (p.R227H) mutation. Thus, copy number abnormalities at the OCTN2 locus should be considered if by sequencing, an apparently homozygous mutation or only one mutant allele is identified.
Li
Fang-Yuan
FY
Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.
El-Hattab
Ayman W
AW
Bawle
Erawati V
EV
Boles
Richard G
RG
Schmitt
Eric S
ES
Scaglia
Fernando
F
Wong
Lee-Jun
LJ
D000293:Adolescent; D000328:Adult; D002331:Carnitine / Q000097:blood / Q000172:deficiency*; D002648:Child; D055028:Comparative Genomic Hybridization; D004252:DNA Mutational Analysis; D005260:Female; D006720:Homozygote; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009154:Mutation / Q000235:genetics*; D020125:Mutation, Missense / Q000235:genetics; D015997:Neonatal Screening; D027701:Organic Cation Transport Proteins / Q000235:genetics*; D000074058:Solute Carrier Family 22 Member 5; D055815:Young Adult
D027701:Organic Cation Transport Proteins; C492020:SLC22A5 protein, human; D000074058:Solute Carrier Family 22 Member 5; D002331:Carnitine