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SPANX-B and SPANX-C (Xq27 region) gene dosage analysis in Down's syndrome subjects with undescended testes

  • Autori: Salemi, M.; Romano, C.; Barone, C.; Calí, F.; Caraci, F.; Romano, C.; Scavuzzo, C.; Scillato, F.; Salluzzo, M.; Piccione, M.; Martines, M.; Corsello, G.; Nicoletti, F.; Bosco, P.
  • Anno di pubblicazione: 2009
  • Tipologia: Articolo in rivista (Articolo in rivista)
  • OA Link:


Down’s syndrome (DS) is one of the most common numer- ical chromosomal aberrations, usually caused by trisomy of chromosome 21, and is frequently complicated with congen- ital heart defects, duodenal obs truction and other conditions including undescended testis (UDT) (Fonkalsrud 1970). The incidence of undescended testes in DS was reported to be 6.52% (Chew and Hutson 2004) while the incidence of UDT in the first year is approximately 0.2%–0.8% in the nor- mal population (Benson et al . 1991; Ichiyanagi et al . 1998). Rapley et 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 least one bilateral case, corresponding to a genome-wide signifi- cance level of P = 0 . 034. The proportion of families with undescended 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 region and seven highly homologous genes belonging to this fam- ily have been described ( SPANX-A1, SPANX-A2, SPANX-B1, SPANX-B2, SPANX-C, SPANX-D and SPANX-E ) according to the human genome database build 36.2. These genes, made up of two exons separated by a small intron of ≈ 650 bp, are expressed in sperm cells (Westbrook et al . 2000) and in many tumours (Wang et al . 2003; Zendman et al . 2003; Westbrook et al . 2004). Moreover, expression of SPANX genes has been demonstrated in TGCT (Salemi et al . 2006). The function of SPANX gene-encoded proteins is currently unknown, and it is also not known if all the members or some of them are normally expressed in the testis (West- brook et al . 2000). Evidence suggests that CTp11 ,which is 100% homologous to SPANX-C , is expressed in tumours such as melanoma (Zendman et al . 2003), and SPANX-B in myeloma and other haematological malignancies (Wang et al . 2003; Zendman et al . 2003). SPANX-C mRNA was found expressed in normal tissues and in embryonal carcinomas of the testis (Salemi et al . 2006). Further, it is very di ffi cult to design primers adequate for gene-specific PCR amplification within the SPANX locus. For this reason, we decided to fo- cus our study on SPANX-C and SPANX-B genes. The aim of this study is to evaluate the genetic variability of SPANX-B and SPANX-C in D.UDT (Down’s syndrom patients a ff ected by undescended testis) compared with D (Down’s syndrom patients without undescended testis) and Nm (normal popu- lation).