PubMed · 2311267
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R Cruz-Coke. 1990. Complex familial translocation.. https://doi.org/10.1111/j.1399-0004.1990.tb03494.x
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Two recent studies have described allelic loss of an RB1 intragenic marker on chromosome 13q in aggressive and metastatic pituitary tumors that did not correlate with loss of pRB. The second report also showed that losses were more frequently associated with a more centromeric marker. Because both of these studies suggest the presence of another or other tumor suppressor genes (TSGs) on 13q, we carried out an allelotype analysis encompassing known and recently described TSG loci on 13q, together with immunohistochemical analysis of pRB. We analyzed 82 nonfunctional tumors and 53 somatotrophinomas subdivided into invasive and noninvasive cohorts. A significantly higher frequency of loss, at one or more of 13 markers, was evident in the invasive nonfunctional tumors (54%, 26 of 48) than in their noninvasive counterparts (29%, 10 of 34). An approximately equal frequency of loss was apparent in invasive (28%, 5 of 18) and noninvasive (31%, 11 of 35) somatotrophinomas at one or more markers. In those tumors harboring deletion, loss at two or more markers was more frequent in invasive nonfunctional tumors 65% (17 of 26) compared with 36% (4 of 11) of their noninvasive counterparts. In somatotrophinomas, 40% (2 of 5) of invasive tumors as compared with 64% (7 of 11) of noninvasive tumors had evidence of two or more deletions. In tumors showing loss at two or more loci, the majority showed large deletions; however, loss of the RB1 intragenic marker D13S153 was infrequent. In most cases, loss at individual markers was more frequent in invasive tumors than their noninvasive counterparts. A marker 3 cM telomeric to RB1 (D13S1319) showed the highest frequency of deletion in both invasive cohorts (29% of somatotrophinomas and 24% of nonfunctional tumors). Immunohistochemical analysis of pRB showed frequent loss in somatotrophinomas (27%, 9 of 33) in comparison with 4% (2 of 53) of non-functional tumors. Although loss of pRB did not correlate with loss of an intragenic marker or tumor grade, it was significantly associated with the somatotrophinoma subtype (P = 0.002). These data suggest that chromosome 13q is a frequent target for allelic deletion in pituitary tumors and point to another or other TSG loci in these regions.
Male factor infertility accounts for about half the cases of couple infertility. In more than 60% of cases the origin of reduced testicular function is unknown but they may have an unidentified genetic anomaly. Microdeletions of the long arm of the human Y chromosome are associated with spermatogenic failure and have been used to define three regions of Yq (AZFa, AZFb and AZFc) that are recurrently deleted in infertile males. Several genes have been identified within this region and have been proposed as candidates for infertility. Many of these genes encode proteins involved in post-transcriptional gene expression and therefore could participate in the sperm maturation process. About 10-15% of azoospermic and about 5-10% of severely oligozoospermic men have Yq microdeletions. The deletions are associated with a wide range of histological pictures ranging from Sertoli Cell Only Syndrome (SCOS) to spermatogenic arrest and severe hypospermatogenesis. Assisted reproduction techniques such as in vitro fertilization (IVF) and Intra Cytoplasmic Sperm Injection (ICSI) alone, or in association with testicular sperm retrieval, represent an efficient therapy for these patients. However the potential of these techniques to transmit genetic defects causing male infertility raises the need for a systematic genetic screening and genetic counselling of these patients.
A well-known association exists between the presence of a chromosome 22q11 micro-deletion and conotruncal heart malformations. Recently, there has been an increased appreciation of the expanded clinical phenotype associated with this chromosome abnormality. We performed a medical record review to evaluate the incidence of renal anomalies in a group of 15 patients ascertained in a single medical center over a 33-month period. Of the 15 patients, 13 had a renal sonogram performed. Five of 13 patients studied (38.4%) had a renal anomaly. The specific abnormalities identified included: bilateral duplex kidneys (1 patient), unilateral renal agenesis (1 patient), unilateral multicystic dysplastic kidneys (2 patients, including 1 ascertained prenatally), and bilateral, extremely small (less than 2 SD below mean) kidneys (1 patient). The incidence of renal anomalies in our patient population (38.4%) was higher than expected, and agrees with a recent European collaborative study. The present report and the European study both demonstrate a higher percentage of renal abnormalities than the 10% previously reported in the literature. Because patients affected with chromosome 22q11 micro-deletion often have multiple medical and surgical problems, we recommend obtaining a baseline renal ultrasound examination to identify renal anomalies before they become symptomatic.