Test code: 2674
Mnemonic code: AZF
Effective update from 30/09/2024
Starting on September 30th, and as a result of the change in the CE IVD commercial kit, the way study results are reported will be modified, in compliance with the current scientific guidelines on the matter.
Below is an example of the report:
GENETIC STUDY OF CHROMOSOME Y MICRODELETIONS - REGIONS AZFa, AZFb, AZFc
Study information and sample
Sample type received EDTA whole blood
Study REGIONS: AZFa, AZFb, AZFc
MIM NUMBER: 415000
INHERITANCE: Y-LINKED
Result
The lack of amplification for sY254 and sY255 markers on chromosome Y suggest the presence of a deletion in AZFc region spanning DAZ gene. The pattern of amplification for extension markers is furthermore consistent with the presence of a complete AZFc deletion (b2/b4).
|
STS analysed
markers (region) |
Result |
|
ZFXY (Yp11.2, Xp22.11) |
Present |
|
sY14 (Yp11.2) |
Present |
|
sY86 (Yq11.221, AZFa) |
Present |
|
sY84 (Yq11.221, AZFa) |
Present |
|
sY127 (Yq11.223, AZFb) |
Present |
|
sY134 (Yq11.223, AZFb) |
Present |
|
sY254 (Yq11.23, AZFc, DAZ gene specific) |
Absent |
|
sY255 (Yq11.23, AZFc, DAZ gene specific) |
Absent |
|
Extension |
Result |
|
sY160 (Yq12, heterochromatin) |
Present |
This result has been confirmed by repeating the analysis on the same sample.
Interpretation
Results are
consistent with the presence of a complete removal of the AZFc region on Y
chromosome (b2/b4) associated with non-obstructive azoospermia or severe
oligozoospermia, being the most likely cause of the patient’s phenotype.
Complete deletion
of AZFc region is associated with a variable phenotype as it is generally
compatible with residual spermatogenesis. In case of azoospermia and AZFc
region interstitial deletion (as the present one) the probability of obtaining
spermatozoa by TESE and conceiving offspring by ICSI is approximately 50%. It
is important to assess the possibility of deletion transmission to all male
offspring (but none of his female offspring) before performing IVF-ICSI.
Genetic
counselling is recommended as well as karyotype analysis for the detection of
45,X0/46,XY mosaicism and testing of the male relatives.
Y-chromosomal
microdeletions are the second most frequent cause of male infertility, they
occur in about 1/4000 men frequency in the general population, significantly
increased in infertile men (about 5%). The most frequent deletion type is AZFc
region deletion (~80%) followed by AZFa (0.5–4%), AZFb (1–5%) and AZFbc (1–3%)
deletion.
This report
should be evaluated by a specialist in the context of all available clinical
and family information in conjunction with other laboratory findings.
Test method
DNA extraction
followed by fluorescent PCR amplification (CE-IVD method) of the following
markers: ZFXY (located on the short arm of chromosomes X and Y), sY14 (located
in Yp11.2), sY86, sY84, sY82, sY83,
sY1065 and sY88 (located in AZFa region), sY127, sY134, sY105, sY121, sY1192
and sY153 (located in AZFb region), sY254 and sY255 (specific for DAZ gene in
AZFc region), sY160 (located in heterochromatin).
ZFXY
amplification as internal PCR control. Detection and fragment analysis is
performed by capillary electrophoresis on Applied Biosystems automated
sequencer.
Test limitations
Sensitivity for
detection of clinically relevant deletions in all three AZF regions is
approximately >97%. Specificity is >99%. In case clinical suspicion
persists, contacting laboratory to evaluate further studies is recommended.
The assay does
not exclude point mutations or rearrangements in DAZ gene, or other possible
microdeletions or rearrangements in genomic locations other than analysed.
Karyotype study
is recommended in case it has not been performed.
References
Lange J et al.
(2008) Nucleic Acids Res 36(Database issue): D809-D814.
Wu Q et al.
(2011) Asian J Androl. 13(6):877-880.
Krausz C et al. (2014)
Andrology. 2(1):5-19
Krausz C et al. (2023) Andrology; 1-18.
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