Penetrance of breast cancer, ovarian cancer and contralateral breast cancer in BRCA1 and BRCA2 families: high cancer incidence at older age.

Accurate estimations of lifetime risks of breast and ovarian cancer are crucial for counselling women from BRCA1/2 families. We therefore determined breast and ovarian cancer penetrance in BRCA1/2 mutation families in the northern Netherlands and compared them with the incidence of cancers in the general population in this region. We identified 1188 female mutation carriers and first-degree female relatives in 185 families with a pathogenic BRCA1 or BRCA2 mutation.

Time to stop ovarian cancer screening in BRCA1/2 mutation carriers?

Women at high risk of ovarian cancer due to a genetic predisposition may opt for either surveillance or prophylactic bilateral salpingo-oophorectomy (pBSO). Main objective of our study was to determine the effectiveness of ovarian cancer screening in women with a BRCA1/2 mutation. We evaluated 241 consecutive women with a BRCA1 or BRCA2 mutation who were enrolled in the surveillance program for hereditary ovarian cancer from September 1995 until May 2006 at the University Medical Center Groningen (UMCG), The Netherlands.

Fishing for a diagnosis.

A family with primary infertility and two members with mental retardation and subtle facial dysmorphism is described. In the two retarded persons chromosomal rearrangements (partial monosomy of chromosome 5 and partial trisomy of chromosome 7) were detected. One member of the family had died with major congenital malformations.

Two unbalanced segregation products due to a maternal t(7;16)inv(16).

We report a prenatal case of a maternally inherited abnormal chromosome 16, originally interpreted as a pericentric inversion only, but after family studies re-interpreted as a pericentric inversion (16) accompanied by an unbalanced (7;16) translocation. Because of the inversion 16 and an elder son with developmental delay and craniofacial dysmorphic features, in the past karyotyped as 46,XY, the chromosomes 16 of the mother and son were carefully re-examined. Using a whole chromosome 16 paint and sub-telomere probes of 16p and 16q, the karyotype of the mother was shown to be 46,XX,inv(16)(p11.

Phenotypic variability of Cat-Eye syndrome.

Cat-Eye syndrome (CES) is a disorder with a variable pattern of multiple congenital anomalies of which coloboma of the iris and anal atresia are the best known. CES is cytogenetically characterised by the presence of an extra bisatellited marker chromosome, which represents an inverted dicentric duplication of a part of chromosome 22 (inv dup(22)). We report on three CES-patients who carry an inv dup(22) diagnosed with FISH studies.

Molecular cytogenetic characterization of a small, familial supernumerary ring chromosome 7 associated with mental retardation and an abnormal phenotype.

A family is described in which a mother and two of her children were mosaic for a small supernumerary ring chromosome. As the origin of the ring chromosome could not be determined by routine cytogenetic studies, fluorescent in situ hybridization was performed, which indicated that the ring chromosome was derived from the pericentromeric region of chromosome 7. Further characterization with a YAC-probe showed the involvement of the proximal q-arm of chromosome 7.

11q- syndrome: three cases and a review of the literature.

We report on three children with de novo terminal deletions of the long arm of chromosome 11 (11q-) and breakpoints in 11q23-q24. Eighty-nine other patients with partial monosomy 11q have been reported and were reviewed by us. Salient features of 11q- syndrome are psychomotor retardation, trigonocephaly, telecanthus/hypertelorism, broad depressed nasal bridge, micrognathia, low set abnormal ears, cardiac anomalies and hand/foot anomalies.

Maternal uniparental disomy for chromosome 14 in a boy with a normal karyotype.

We report on a boy with a maternal uniparental disomy for chromosome 14 (UPD(14)). At 7 years of age he was referred to us by the paediatrician because of symptoms of Prader-Willi syndrome (PWS). He showed short stature, obesity, mild developmental delay, cryptorchidism, and some mild dysmorphic features.

Tetrasomy 9p due to an intrachromosomal triplication of 9p13-p22.

To date, approximately 30 patients have been described with a tetrasomy 9p, all being caused by the presence of an isochromosome 9p. We now report on a 3-year-old boy with a de novo intrachromosomal triplication of 9p13-p22, resulting in partial tetrasomy 9p. We compared his phenotype with cases of tetrasomy 9p caused by the presence of an extra isochromosome 9p.

Three cases of mosaicism for balanced reciprocal translocations.

Mosaicism for a balanced reciprocal translocation (BRTM) is rare. As far as we know only 26 cases of BRTM, demonstrated in lymphocyte cultures, have been described, five of which had an abnormal phenotype. Prenatally three confirmed cases with a normal phenotypic outcome have been described.

Trisomy 1q42 --> qter in a sister and brother: further delineation of the "trisomy 1q42 --> qter syndrome".

We report on a 22-year-old woman and her 21-year-old brother with mild mental retardation, long face, prominent forehead, retrognathia, and (relative) macrocephaly. At birth they were small for date, their length is now below the 10th centile. Chromosome analysis demonstrated a nearly pure trisomy 1q42 --> qter in both patients due to unbalanced segregation of a paternal reciprocal balanced translocation 46,XY,t(1;15) (q42;p11).

Bilateral split hand/foot malformation and inv(7)(p22q21.3).

A boy with typical tetramelic split hands and feet is described. In addition, there was a large arteriovenous malformation of the right arm. Chromosome studies showed a pericentric inversion of chromosome 7: 46,XY,inv(7)(p22q21.

Tetrasomy 5p mosaicism in a boy with delayed growth, hypotonia, minor anomalies, and an additional isochromosome 5p [46,XY/47,XY, + i(5p)].

We describe a 1-year-old boy with a rare de novo 46,XY/47,XY, + i(5p) mosaicism (ratios 28/3 in peripheral blood lymphocytes and 2/12 in skin fibroblasts). The boy, born after a pregnancy of 34 weeks, had lung hypoplasia, persistent hypotonia, and postnatal growth failure. Craniofacial anomalies were also present.

Isochromosome 18q in a girl with holoprosencephaly, DiGeorge anomaly, and streak ovaries.

We report on the clinical and pathologic findings in a girl with isochromosome 18q (46, XX,i(18q)) who had combined manifestations of monosomy 18p and trisomy 18q. Major congenital anomalies included premaxillary agenesis, alobar holoprosenphaly, double outlet right ventricle, DiGeorge anomaly and streak ovaries. The clinical spectrum in i(18q) is very broad.