Frequencies of HKαα and anti-HKαα Alleles in Chinese Carriers of Silent Deletional α-Thalassemia.
The HKαα (HongKongαα) allele is an unusual rearrangement of the α-globin gene cluster containing both the -α(3.7) (rightward) and ααα(anti 4.2) crossover deletion/duplication. The anti-HKαα (anti-HongKongαα) allele is the reciprocal product containing both the -α(4.2) (leftward) and ααα(anti 3.7) unequal crossover deletion/duplication. In clinical practice of thalassemia screening, gap-polymerase chain reaction (gap-PCR) approaches are used to detect the common -α(3.7) and -α(4.2) deletions of α-thalassemia (α-thal). Because the HKαα and anti-HKαα alleles also contain the single α-globin gene deletion, individuals with these alleles would be misdiagnosed as -α(3.7) or -α(4.2) carriers. This would likely produce misleading or incorrect information in genetic counseling. In this study, we investigated the HKαα and anti-HKαα alleles in Chinese carriers of silent deletional α-thal, and reported their frequencies to be 2.27 and 0.35% in -α(3.7) and -α(4.2) carriers, respectively. Given the rarity of the HKαα and anti-HKαα alleles, a routine screening for these two rearrangements are unlikely to be necessary on most occasions.
a Prenatal Diagnostic Center, Guangzhou Women & Children Medical Center affiliated to Guangzhou Medical University , Guangzhou , Guangdong , People's Republic of China.
Man-Yu
MY
Wu
a Prenatal Diagnostic Center, Guangzhou Women & Children Medical Center affiliated to Guangzhou Medical University , Guangzhou , Guangdong , People's Republic of China.
Jian
J
Li
a Prenatal Diagnostic Center, Guangzhou Women & Children Medical Center affiliated to Guangzhou Medical University , Guangzhou , Guangdong , People's Republic of China.
Shu-Chen
SC
Li
b Guangzhou Cord Blood Bank, Guangzhou Women & Children Medical Center affiliated to Guangzhou Medical University , Guangzhou , Guangdong , People's Republic of China.
Yan
Y
Li
a Prenatal Diagnostic Center, Guangzhou Women & Children Medical Center affiliated to Guangzhou Medical University , Guangzhou , Guangdong , People's Republic of China.
Dong-Zhi
DZ
Li
D000328:Adult; D000483:Alleles; D044466:Asian People / Q000235:genetics*; D002681:China / Q000453:epidemiology; D004909:Erythrocyte Indices; D005260:Female; D005787:Gene Frequency; D056426:Genetic Loci; D006579:Heterozygote; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011247:Pregnancy; D011296:Prenatal Diagnosis; D017384:Sequence Deletion; D055815:Young Adult; D055542:alpha-Globins / Q000235:genetics*; D017085:alpha-Thalassemia / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*
D055542:alpha-Globins
Chinese; HKαα (HongKongαα) allele; anti-HKαα (anti-HongKongαα) allele; two-round polymerase chain reaction (PCR); α-Globin gene rearrangement