Germline mutations in FH predispose to dominantly inherited uterine fibroids, skin leiomyomata and papillary renal cell cancer.

Uterine leiomyomata (fibroids) are common and clinically important tumors, but little is known about their etiology and pathogenesis. We previously mapped a gene that predisposes to multiple fibroids, cutaneous leiomyomata and renal cell carcinoma to chromosome 1q42.3-q43 (refs 4-6). Here we show, through a combination of mapping critical recombinants, identifying individuals with germline mutations and screening known and predicted transcripts, that this gene encodes fumarate hydratase, an enzyme of the tricarboxylic acid cycle. Leiomyomatosis-associated mutations are predicted to result in absent or truncated protein, or substitutions or deletions of highly conserved amino acids. Activity of fumarate hydratase is reduced in lymphoblastoid cells from individuals with leiomyomatosis. This enzyme acts as a tumor suppressor in familial leiomyomata, and its measured activity is very low or absent in tumors from individuals with leiomyomatosis. Mutations in FH also occur in the recessive condition fumarate hydratase deficiency, and some parents of people with this condition are susceptible to leiomyomata. Thus, heterozygous and homozygous or compound heterozygous mutants have very different clinical phenotypes. Our results provide clues to the pathogenesis of fibroids and emphasize the importance of mutations of housekeeping and mitochondrial proteins in the pathogenesis of common types of tumor.

Frequency and spectrum of cancers in the Peutz-Jeghers syndrome.

BACKGROUND: Although an increased cancer risk in Peutz-Jeghers syndrome is established, data on the spectrum of tumors associated with the disease and the influence of germ-line STK11/LKB1 (serine/threonine kinase) mutation status are limited. EXPERIMENTAL DESIGN: We analyzed the incidence of cancer in 419 individuals with Peutz-Jeghers syndrome, and 297 had documented STK11/LKB1 mutations. RESULTS: Ninety-six cancers were found among individuals with Peutz-Jeghers syndrome. The risk for developing cancer at ages 20, 30, 40, 50, 60, and 70 years was 2%, 5%, 17%, 31%, 60%, and 85%, respectively. The most common cancers represented in this analysis were gastrointestinal in origin, gastroesophageal, small bowel, colorectal, and pancreatic, and the risk for these cancers at ages 30, 40, 50, and 60 years was 1%, 9%, 15%, and 33%, respectively. In women with Peutz-Jeghers syndrome, the risk of breast cancer was substantially increased, being 8% and 31% at ages 40 and 60 years, respectively. Kaplan-Meier analysis showed that cancer risks were similar in Peutz-Jeghers syndrome patients with identified STK11/LKB1 mutations and those with no detectable mutation (log-rank test of difference chi2 = 0.62; 1 df; P = 0.43). Furthermore, the type or site of STK11/LKB1 mutation did not significantly influence cancer risk. CONCLUSIONS: The results from our study provide quantitative information on the spectrum of cancers and risks of specific cancer types associated with Peutz-Jeghers syndrome.

Sequence changes in predicted promoter elements of STK11/LKB1 are unlikely to contribute to Peutz-Jeghers syndrome.

BACKGROUND: Germline mutations or large-scale deletions in the coding region and splice sites of STK11/LKB1 do not account for all cases of Peutz-Jeghers syndrome (PJS). It is conceivable that, on the basis of data from other diseases, inherited variation in promoter elements of STK11/LKB1 may cause PJS. RESULTS: Phylogenetic foot printing and transcription factor binding site prediction of sequence 5' to the coding sequence of STK11/LKB1 was performed to identify non-coding sequences of DNA indicative of regulatory elements. A series of 33 PJS cases in whom no mutation in STK11/LKB1 could be identified were screened for sequence changes in the putative promoter defined by nucleotides -1090 to -1472. Two novel sequence changes were identified, but were found to be present in healthy individuals. CONCLUSION: These findings indicate that promoter sequence changes are unlikely to contribute to PJS.

Contribution of germline mutations in BRCA2, P16(INK4A), P14(ARF) and P15 to uveal melanoma.

PURPOSE: Reports suggest that a subset of uveal melanoma is familial. The association of uveal melanoma with breast and ovarian cancer and the increased risk in BRCA2-linked families implicates germline BRCA2 mutations as the cause of a subset of uveal melanomas. Similarly, the association between cutaneous and uveal melanomas in some families, coupled with the high frequency of somatic deletions of the INK4A-ARF locus in uveal melanomas, strongly suggests that mutations in P16(INK4A) and P15 account for a proportion of uveal melanomas. METHODS: To examine this proposition, a systematically ascertained series of 385 patients with uveal melanoma were screened for germline mutations in BRCA2, P16(INK4A), P14(ARF), and P15. RESULTS: One patient was found to harbor a Gly35Ala substitution in exon 1alpha of P16(INK4A), which has previously been reported to be pathogenic. No mutations were detected in P14(ARF) or P15. None of the patients harbored germline nucleotide changes that lead to truncation or that create or disrupt consensus splice sites of BRCA2 or missense variants with clear pathogenic potential. CONCLUSIONS: These findings suggest that less than 2% of cases of uveal melanoma can be ascribed to germline mutations in BRCA2, P16(INK4A), P14(ARF), or P15. It is likely that mutations in other genes contribute to an inherited predisposition to uveal melanoma.

Mapping of a translocation breakpoint in a Peutz-Jeghers hamartoma to the putative PJS locus at 19q13.4 and mutation analysis of candidate genes in polyp and STK11-negative PJS cases.

Germ-line mutations in the serine-threonine kinase gene STK11 (LKB1) cause Peutz-Jeghers syndrome (PJS), a rare autosomal dominantly inherited disease, characterized by hamartomatous polyposis and mucocutaneous pigmentation. STK11 mutations only account for about half of PJS cases, and a second disease locus has been proposed at chromosome segment 19q13.4 on the basis of genetic linkage analysis in one family. We identified a t(11;19)(q13;q13.4) in a PJS polyp arising from the small bowel in a female infant age 6 days. Because the breakpoint in 19q13.4 may disrupt the putative PJS disease gene mapping to this region, we mapped the breakpoint and analyzed DNA from the case and a series of STK11-negative PJS cases. Using two-color interphase fluorescence in situ hybridization, the breakpoint region was refined to a 0.5-Mb region within 19q13.4. Eight candidate genes mapping to the breakpoint region--U2AF2, EPN1, NALP4, NALP11, NALP5, ZNF444, PTPRH, and KIAA1811--were screened for mutations in germ-line and polyp DNA from the case and from 15 PJS cases that did not harbor germ-line STK11 mutations. No pathogenic mutations in the candidate genes were identified. This report provides further evidence of the existence of a second PJS disease locus at 19q13.4 and excludes involvement of eight candidate genes.