Y chromosome microdeletion

Short description: Family of genetic disorders caused by missing genes in the Y chromosome

Y chromosome microdeletion (YCM) is a family of genetic disorders caused by missing genes in the Y chromosome. Many men with YCM exhibit no symptoms and lead normal lives. It is present in a significant number of men with reduced fertility.[1] Reduced sperm production varies from oligozoospermia, significant lack of sperm, or azoospermia, complete lack of sperm.

## Contents

* 1 Cause
* 2 Diagnosis
* 3 Infertility
* 4 See also
* 5 References
* 6 Further reading

## Cause

The mechanism of mutation is not different for Y-chromosome microdeletion. However, the ability to repair it differs from other chromosomes. The human Y chromosome is passed directly from father to son, and is not protected against accumulating copying errors, whereas other chromosomes are error corrected by recombining genetic information from mother and father. This may leave natural selection as the primary repair mechanism for the Y chromosome.[citation needed]

## Diagnosis

Y chromosome microdeletion is currently diagnosed by extracting DNA from leukocytes in a man's blood sample, mixing it with some of the about 300 known genetic markers for sequence-tagged sites (STS) on the Y chromosome, and then using polymerase chain reaction amplification and gel electrophoresis in order to test whether the DNA sequence corresponding to the selected markers is present in the DNA.[citation needed]

Such procedures can test only the integrity of a tiny part of the overall 23 million base pair long Y chromosome. Therefore, the sensitivity of such tests depends on the choice and number of markers used. Present diagnostic techniques can only discover certain types of deletions and mutations on a chromosome and give therefore no complete picture of genetic causes of infertility. They can only demonstrate the presence of some defects, but not the absence of any possible genetic defect on the chromosome.[citation needed]

The preferred test for genetic mutation, namely complete DNA sequencing of a patient's Y chromosome, is too expensive for use in epidemiological research or clinical diagnostics.[citation needed]

In up to 20% of men with reduced sperm count, some form of YCM has been detected.[2]

## Infertility

Microdeletions in the Y chromosome have been found at a much higher rate in infertile men than in fertile controls[3] and the correlation found may still go up as improved genetic testing techniques for the Y chromosome are developed.[citation needed]

Much study has been focused upon the "azoospermia factor locus" (AZF), at Yq11.[4] A specific partial deletion of AZFc called gr/gr deletion is significantly associated with male infertility among Caucasians in Europe and the Western Pacific region.[5]

Additional genes associated with spermatogenesis in men and reduced fertility upon Y chromosome deletions include RBM, DAZ, SPGY, and TSPY.[6]

## See also

* Infertility
* AZF1

## References

1. ↑ Carlo Foresta, et al.: Y chromosome microdeletions and alterations of spermatogenesis. Endocrine Reviews 22 (2): 226-239.
2. ↑ Krausz, Csilla; Lluis Quintana-Murci; Ken McElreavey (July 2000). "Prognostic value of Y deletion analysis". Human Reproduction 15 (7): 1431–1434. doi:10.1093/humrep/15.7.1431. PMID 10875846. http://humrep.oxfordjournals.org/cgi/content/full/15/7/1431.
3. ↑ "Screening for Y chromosome microdeletions in idiopathic and nonidiopathic infertile men with varicocele and cryptorchidism". Chin. Med. J. 118 (17): 1462–7. September 2005. PMID 16157049. http://www.cmj.org/Periodical/LinkIn.asp?journal=Chinese Medical Journal&linkintype=pubmed&year=2005&vol=118&issue=17&beginpage=1462.
4. ↑ "Genetics of human male infertility". Singapore Med J 50 (4): 336–47. April 2009. PMID 19421675. http://smj.sma.org.sg/5004/5004ra1.pdf.
5. ↑ Stouffs, K.; Lissens, W.; Tournaye, H.; Haentjens, P. (2010). "What about gr/gr deletions and male infertility? Systematic review and meta-analysis". Human Reproduction Update 17 (2): 197–209. doi:10.1093/humupd/dmq046. PMID 20959348.
6. ↑ Goncalves, J; Lavinha J. (April 1998). "Y chromosome and male infertility" (in pt). Acta Med Port 11 (4): 365–72. PMID 9644848.

## Further reading

* GeneReviews/NCBI/NIH/UW entry on Y Chromosome Infertility

* v
* t
* e

Chromosome abnormalities (Q90–Q99, 758)

Autosomal|

| Trisomies|

* Down syndrome
* 21
* Edwards syndrome
* 18
* Patau syndrome
* 13

* Trisomy 9
* Warkany syndrome 2
* 8
* Cat eye syndrome/Trisomy 22
* 22
* Trisomy 16

|

Monosomies/deletions|

* 1q21.1 deletion syndrome/1q21.1 duplication syndrome/TAR syndrome
* 1
* Wolf–Hirschhorn syndrome
* 4
* Cri du chat/Chromosome 5q deletion syndrome
* 5
* Williams syndrome
* 7
* Jacobsen syndrome
* 11
* Miller–Dieker syndrome/Smith–Magenis syndrome
* 17
* DiGeorge syndrome
* 22
* 22q11.2 distal deletion syndrome
* 22
* 22q13 deletion syndrome
* 22

* genomic imprinting
* Angelman syndrome/Prader–Willi syndrome (15)

* Distal 18q-/Proximal 18q-

X/Y linked|

| Monosomy|

* Turner syndrome (45,X)

|

Trisomy/tetrasomy,
other karyotypes/mosaics|

* Klinefelter syndrome (47,XXY)
* XXYY syndrome (48,XXYY)
* XXXY syndrome (48,XXXY)
* 49,XXXYY
* 49,XXXXY

* Triple X syndrome (47,XXX)
* Tetrasomy X (48,XXXX)
* 49,XXXXX

* Jacobs syndrome (47,XYY)
* 48,XYYY
* 49,XYYYY

* 45,X/46,XY

Translocations|

| Leukemia/lymphoma|

| Lymphoid|

* Burkitt's lymphoma t(8 MYC;14 IGH)
* Follicular lymphoma t(14 IGH;18 BCL2)
* Mantle cell lymphoma/Multiple myeloma t(11 CCND1:14 IGH)
* Anaplastic large-cell lymphoma  t(2 ALK;5 NPM1)
* Acute lymphoblastic leukemia

|

Myeloid|

* Philadelphia chromosome t(9 ABL; 22 BCR)
* Acute myeloblastic leukemia with maturation t(8 RUNX1T1;21 RUNX1)
* Acute promyelocytic leukemia t(15 PML,17 RARA)
* Acute megakaryoblastic leukemia t(1 RBM15;22 MKL1)

Other|

* Ewing's sarcoma t(11 FLI1; 22 EWS)
* Synovial sarcoma t(x SYT;18 SSX)
* Dermatofibrosarcoma protuberans t(17 COL1A1;22 PDGFB)
* Myxoid liposarcoma t(12 DDIT3; 16 FUS)
* Desmoplastic small-round-cell tumor t(11 WT1; 22 EWS)
* Alveolar rhabdomyosarcoma t(2 PAX3; 13 FOXO1) t (1 PAX7; 13 FOXO1)

Other|

* Fragile X syndrome
* Uniparental disomy
* XX male syndrome/46,XX testicular disorders of sex development
* Marker chromosome
* Ring chromosome
* 6; 9; 14; 15; 18; 20; 21, 22

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