Prevalence and distribution of the c.1436C→T sequence variant of carnitine palmitoyltransferase 1A among Alaska Native infants.
OBJECTIVE
To use genotype analysis to determine the prevalence of the c.1436C→T sequence variant in carnitine palmitoyltransferase 1A (CPT1A) among Alaskan infants, and evaluate the sensitivity of newborn screening by tandem mass spectrometry (MS/MS) to identify homozygous infants.


METHODS
We compared MS/MS and DNA analyses of 2409 newborn blood spots collected over 3 consecutive months.


RESULTS
Of 2409 infants, 166 (6.9%) were homozygous for the variant, all but one of whom were of Alaska Native race. None of the homozygous infants was identified by MS/MS on the first newborn screen using a C0/C16 + C18 cutoff of 130. Among 633 Alaska Native infants, 165 (26.1%) were homozygous and 218 (34.4%) were heterozygous for the variant. The prevalence was highest in Alaska's northern/western regions (51.2% of 255 infants homozygous; allele frequency, 0.7).


CONCLUSIONS
The CPT1A c.1436C→T variant is prevalent among some Alaska Native peoples, but newborn screening using current MS/MS cutoffs is not an effective means to identify homozygous infants. The clinical consequences of the partial CPT1A deficiency associated with this variant are unknown. If effects are substantial, revision of newborn screening, including Alaska-specific MS/MS cutoffs and confirmatory genotyping, may be needed.
Gessner
Bradford D
BD
Alaska Division of Public Health, Anchorage, AK, USA. Brad.Gessner@alaska.gov
Gillingham
Melanie B
MB
Johnson
Monique A
MA
Richards
C Sue
CS
Lambert
William E
WE
Sesser
David
D
Rien
Leanne C
LC
Hermerath
Cheryl A
CA
Skeels
Michael R
MR
Birch
Stephanie
S
Harding
Cary O
CO
Wood
Thalia
T
Koeller
David M
DM
D000413:Alaska; D002334:Carnitine O-Palmitoyltransferase / Q000172:deficiency / Q000235:genetics*; D006720:Homozygote; D006801:Humans; D007198:Indians, North American; D007231:Infant, Newborn; D015997:Neonatal Screening; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry
D002334:Carnitine O-Palmitoyltransferase