Fragile X-related element 2 methylation analysis may provide a suitable option for inclusion of fragile X syndrome and/or sex chromosome aneuploidy into newborn screening: a technical validation study.
OBJECTIVE
We show that a novel fragile X-related epigenetic element 2 FMR1 methylation test can be used along with a test for sex-determining region Y (SRY) to provide the option of combined fragile X syndrome and sex chromosome aneuploidy newborn screening.


METHODS
Fragile X-related epigenetic element 2, SRY, and FMR1 CGG repeat analyses were performed on blood and saliva DNA, and in adult and newborn blood spots. The cohort consisted of 159 controls (CGG <40), 187 premutation (CGG 56-170), and 242 full-mutation (CGG ~200-2,000) males and females, 106 sex chromosome aneuploidy individuals, and 151 cytogenetically normal controls.


RESULTS
At the 0.435 threshold, fragile X-related epigenetic element 2 analysis in males was robust on both blood DNA and newborn blood spots, with specificity and sensitivity of ~100% for full-mutation genotype. In females, the specificity was 99%, whereas half of full-mutation females were above the 0.435 threshold in both blood DNA and newborn blood spots. Furthermore, at this threshold, the test could not differentiate individuals with Klinefelter syndrome from female controls without using the SRY marker. When combined with SRY analysis, the test was consistent with most results for sex chromosome aneuploidies from karyotyping.


CONCLUSIONS
Setting specific thresholds for fragile X-related epigenetic element 2 analysis and including the SRY marker provides the option to either include or exclude detection of sex chromosome aneuploidies as part of fragile X syndrome newborn screening.
Victorian Clinical Genetics Services and Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.
Yoshimi
Y
Inaba
Amy S
AS
Herlihy
Charles E
CE
Schwartz
Cindy
C
Skinner
Quang M
QM
Bui
Joanna
J
Cobb
Elva Z
EZ
Shi
David
D
Francis
Alison
A
Arvaj
David J
DJ
Amor
Kate
K
Pope
Tiffany
T
Wotton
Jonathan
J
Cohen
Jacqueline K
JK
Hewitt
Randi J
RJ
Hagerman
Sylvia A
SA
Metcalfe
John L
JL
Hopper
Danuta Z
DZ
Loesch
Howard R
HR
Slater
David E
DE
Godler
D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D000782:Aneuploidy; D002460:Cell Line; D002648:Child; D002675:Child, Preschool; D018899:CpG Islands; D019175:DNA Methylation; D005260:Female; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000235:genetics*; D005600:Fragile X Syndrome / Q000175:diagnosis* / Q000235:genetics*; D018628:Gene Dosage; D024282:Genes, sry; D005820:Genetic Testing / Q000191:economics / Q000379:methods; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007438:Introns; D008297:Male; D008875:Middle Aged; D015997:Neonatal Screening / Q000191:economics / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012729:Sex Chromosome Aberrations; D019680:Trinucleotide Repeat Expansion / Q000235:genetics; D055815:Young Adult
D051860:Fragile X Messenger Ribonucleoprotein 1; C497683:FMR1 protein, human