These observations may help to resolve the issues about how, and to what extent, sperm DNA damage impacts upon the success of IVF and ICSI procedures.

We present the clinical and laboratory findings in an institutionalised adult patient originally referred for autism. A high risk of colorectal cancer was predicted when an interstitial deletion of the long arm of chromosome 5, del(5) (q15q22.3), was detected in her lymphocytes and deletion of the MCC and APC genes confirmed by molecular analysis. Adenomatous polyposis coli and carcinoma of the rectum were subsequently diagnosed in the patient. She was profoundly mentally retarded, autistic, and had minor dysmorphic features consistent with those of previous patients with similar deletions.The deletion arose as a result of recombination within the small insertion loop formed at meiosis by the direct insertion (dir ins(5) (q22.3ql4.2ql5)) found in the patient's mother. This family further confirms the cytogenetic mapping of both MCC and APC genes to 5q22 and comparison with other recent cases suggests that both genes and their closely linked markers lie within the 5q22.1 subband.

Summary Desmoids are locally aggressive. non-metastasizing soft-tissue tumours. whose aetiology is still unclear. In patients affected with familial adenomatous polyposis (FAP), the incidence of desmoids is much higher than in the general population. The

Fluorescent in-situ hybridization (ISH) to interphase nuclei of human preimplantation embryos has been demonstrated with the X and Y chromosome-specific DNA probes, pBamX7 and pHY2.1, respectively. Assigning the sex on the basis of the number of hybridization signals in the majority of nuclei, the efficiencies with both probes to nuclei from male embryos were considerably higher than those previously reported for pHY2.1 detected by isotopic or conventional non-isotopic methods. Only approximately 15% of nuclei from male embryos failed to hybridize with these probes. With pBamX7, a high incidence (18%) of nuclei with two (or more) signals in embryos classified as males and four signals in a female embryo was observed. In some cases, the double spot nuclei were larger than those with single spots, providing evidence of tetraploidy. The feasibility of using fluorescent ISH for sexing biopsied embryos in couples at risk of X-linked disease and for the preimplantation diagnosis of chromosome abnormalities is discussed.