Could the leukocyte x chromosome inactivation pattern be extrapolated to hair bulbs?
BACKGROUND
The androgen receptor gene is located on the X chromosome with a polymorphic tract of CAG repeats that is inversely correlated to the receptor's transactivation activity. A short CAG tract is associated with hyperandrogenic disorders. In women, one of the X chromosomes is inactivated and the X chromosome inactivation (XCI) pattern varies among tissues. Previous studies of hyperandrogenic disorders only evaluated XCI in leukocytes.


OBJECTIVE
To evaluate whether the XCI pattern in leukocytes could be extrapolated to those in hair bulbs.


METHODS
A total of 58 healthy women were used for this study. DNA was extracted from leukocytes (n = 58 women) and pubic (n = 53 women) and scalp hair (n = 21 women).


METHODS
Hpa II digested and undigested DNA samples underwent fluorescence PCR GeneScan analysis.


RESULTS
A significant and positive correlation of XCI was found between leukocytes and hair bulbs. However, individual comparisons showed that 13 and 19% of the women presented a different leukocyte XCI pattern in pubic hair and scalp hair, respectively.


CONCLUSIONS
The XCI pattern was similar in leukocytes and hair bulbs of normal women indicating that leukocyte DNA is useful for XCI analysis. However, the XCI pattern could vary among tissues from the same subject, indicating that care should be taken when extrapolating individual leukocyte XCI patterns to other tissue.
Kaupert
Laura C
LC
Laboratory of Hormones and Molecular Genetics LIM-42, Division of Endocrinology, Clinics Hospital, School of Medicine, São Paulo University, São Paulo, Brazil.
Billerbeck
Ana Elisa C
AE
Brito
Vinícius N
VN
Mendonca
Berenice B
BB
Bachega
Tânia A S S
TA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D002648:Child; D041321:Chromosomes, Human, X / Q000235:genetics / Q000502:physiology*; D004247:DNA / Q000737:chemistry / Q000235:genetics; D019175:DNA Methylation; D005260:Female; D006197:Hair / Q000502:physiology; D018859:Hair Follicle / Q000502:physiology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000502:physiology*; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D018911:Trinucleotide Repeats; D049951:X Chromosome Inactivation / Q000235:genetics / Q000502:physiology*; D055815:Young Adult
D004247:DNA