Down’s syndrome (DS) is one of the most common numer-ical chromosomal aberrations, usually caused by trisomy ofchromosome 21, and is frequently complicated with congen-ital heart defects, duodenal obstruction and other conditionsincluding undescended testis (UDT) (Fonkalsrud 1970). Theincidence of undescended testes in DS was reported to be6.52% (Chew and Hutson 2004) while the incidence of UDTin the first year is approximately 0.2%–0.8% in the nor-mal population (Bensonet al. 1991; Ichiyanagiet al. 1998).Rapleyet al. (2000) provided evidence for a testicular germ-cell tumours (TGCT) predisposition locus at Xq27; the au-thors obtained an hlod score of 4.7 from families with at leastone bilateral case, corresponding to a genome-wide signifi-cance level ofP=0.034. The proportion of families withundescended testis linked to this locus was 74%.SPANX(sperm protein associated with the nucleus in the X chro-mosome) gene family maps in the same chromosomal regionand seven highly homologous genes belonging to this fam-ily have been described (SPANX-A1, SPANX-A2, SPANX-B1,SPANX-B2, SPANX-C, SPANX-DandSPANX-E) accordingto the human genome database build 36.2. These genes,made up of two exons separated by a small intron of≈650bp, are expressed in sperm cells (Westbrooket al. 2000) andin many tumours (Wanget al. 2003; Zendmanet al. 2003;Westbrooket al. 2004). Moreover, expression ofSPANX genes has been demonstrated in TGCT (Salemiet al. 2006).The function ofSPANXgene-encoded proteins is currentlyunknown, and it is also not known if all the members orsome of them are normally expressed in the testis (West-brooket al. 2000). Evidence suggests thatCTp11,whichis 100% homologous toSPANX-C, is expressed in tumourssuch as melanoma (Zendmanet al. 2003), andSPANX-Binmyeloma and other haematological malignancies (Wangetal. 2003; Zendmanet al. 2003).SPANX-CmRNA was foundexpressed in normal tissues and in embryonal carcinomas ofthe testis (Salemiet al. 2006). Further, it is very difficult todesign primers adequate for gene-specific PCR amplificationwithin the SPANX locus. For this reason, we decided to fo-cus our study onSPANX-CandSPANX-Bgenes. The aim ofthis study is to evaluate the genetic variability ofSPANX-BandSPANX-Cin D.UDT (Down’s syndrom patients affectedby undescended testis) compared with D (Down’s syndrompatients without undescended testis) and Nm (normal popu-lation).
|Numero di pagine||5|
|Rivista||Journal of Genetics|
|Stato di pubblicazione||Published - 2009|