[in Japanese]

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[in Japanese]

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[in Japanese]

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Genetic testings for children with inherited genetic diseases could be done for the purpose of the diagnosis, carrier diagnosis and the presymptomatic diagnosis. Moreover, the carrier diagnosis, presymptomatic diagnosis for a family or a client whose symptoms have not appeared yet and prenatal diagnosis could be performed using the genetic information. Our medical staffs that treat genetic issuers have to try to carry out proper genetic counseling, informed consent for protect rights of children and fetus.

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[in Japanese]

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Fanconi anemia （ FA） is a rare autosomal recessive disorder of hematopoiesis, characterized by chromosome instability. FA patients are susceptible to hematopoietic neoplasms such as acute myeloid leukemia and various types of epithelial malignancies. The disease is classified into more than 10 genetically different groups, and 8 FA genes have been identified. These gene products function in a common pathway, in which FANCD2, a downstream component, in collaboration with BRCA1, regulates DNA damage response. Notably, FANCD1 has been proved to be identical with BRCA2. These findings have led to a proposal of the FA/BRCA pathway. FANCD2 also controls the cell cycle checkpoint, by interacting with ATM and NBS1. Fancd2-null mice show an increased incidence of various types of epithelial malignancies. Emerging evidence suggests that the acquired inactivation of FA genes is involved in carcinogenesis/tumor progression and tumor sensitivity to chemotherapeutic DNA crosslinkers.

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An excess of multiple colorectal cancers has been reported in hereditary non-polyposis colorectal cancer （HNPCC）. The management of patients with colorectal cancer（CRC）should include segmental colectomy in cases of sporadic CRC, and prophylactic subtotal colectomy. The patients need to know that an alternative to subtotal colectomy is segmental colectomy followed by lifelong colonoscopic surveillance. The decision to choose the therapeutic option is made in consideration of the following conditions: method of diagnosis, affection of cancer, site of CRC, age at the onset of CRC, tolerance to operation, and anal sphincter function. In cases of families with a history suggestive of HNPCC but in which the Amsterdam criteria have not been fulfilled, decision making is often difficult. Extended hemicolectomy is a procedure in which half the length of the colon is resected. We propose that extended hemicolectomy should be included as one of the therapeutic options for HNPCC.

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Focusing on the clinical features of hereditary nonpolyposis colorectal cancer（HNPCC） in Japan, we have analyzed 311 colorectal cancer（CRC）cases in 62 HNPCC families conform to Amsterdam criteria. Furthermore we compared the findings with those in 346 CRC cases without family history of cancer as controls. Results revealed that the average age of cancer onset in HNPCC was 43.1 years; whereas it was 62.6 years in the controls（CRCs without cancer family history）, and that the rate of patients whose cancer was diagnosed under the age of 50 was 74.7% and 14.8% respectively. As to site, it was found that the colorectal cancer had occurred in the proximal colon of 38.4% of HNPCC patients and in 27.9% of the controls, and that the frequency of rectal cancer was 27.4% and 50.3%, respectively. Also, synchronous or metachronous multiple cancers including multiple colorectal cancers were found to have occurred in 31.9% of HNPCC patients and in 4.8% of the controls. Thus, the clinical features of HNPCC are characterized by an early age of onset, a predominant siting in the proximal colon, and a high incidence of multiple primary neoplasms including multiple colorectal cancers.

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It is often difficult to clinically manage patients with desmoid tumors complicated by familial adenomatous polyposis (FAP). Case 1: A 20-year-old female underwent total colectomy for FAP. The diagnosis of mesenteric desmoid tumor associated with FAP had been made when she underwent surgical treatment for suspicious ovarian tumor at age 19. Administration of sulindac, prednisolone, and tamoxifen resulted in no effect on the intraabdominal and abdominal wall desmoids, and they rapidly grew after the second surgery. She died of ileus due to the progressive desmoid tumors 27 months following the second surgery. Case 2 : A 23-year-old female, who was the elder sister of Case 1, underwent total colectomy for FAP. The desmoid tumor, which developed in the operative scar, was resected 10 months after the primary operation. Administration of sulindac was started after the second operation, but the desmoid recurred 26 months postoperatively. A careful follow-up has been made over the past four months because of its slow growth. Careful consideration is needed when scheduling prophylactic colectomy for patients with FAP whose family members have been affected by desmoid tumors.

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