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result(s) for
"Wieacker, Peter"
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Prevalence of pathogenic BRCA1/2 germline mutations among 802 women with unilateral triple-negative breast cancer without family cancer history
by
Weber, Bernhard H. F.
,
Bartram, Claus R.
,
Wieacker, Peter
in
Biomedical and Life Sciences
,
Biomedicine
,
BRCA1
2018
Background
There is no international consensus up to which age women with a diagnosis of triple-negative breast cancer (TNBC) and no family history of breast or ovarian cancer should be offered genetic testing for germline
BRCA1
and
BRCA2
(gBRCA) mutations. Here, we explored the association of age at TNBC diagnosis with the prevalence of pathogenic gBRCA mutations in this patient group.
Methods
The study comprised 802 women (median age 40 years, range 19–76) with oestrogen receptor, progesterone receptor, and human epidermal growth factor receptor type 2 negative breast cancers, who had no relatives with breast or ovarian cancer. All women were tested for pathogenic gBRCA mutations. Logistic regression analysis was used to explore the association between age at TNBC diagnosis and the presence of a pathogenic gBRCA mutation.
Results
A total of 127 women with TNBC (15.8%) were gBRCA mutation carriers (
BRCA1
:
n
= 118, 14.7%;
BRCA2
:
n
= 9, 1.1%). The mutation prevalence was 32.9% in the age group 20–29 years compared to 6.9% in the age group 60–69 years. Logistic regression analysis revealed a significant increase of mutation frequency with decreasing age at diagnosis (odds ratio 1.87 per 10 year decrease, 95%CI 1.50–2.32,
p
< 0.001). gBRCA mutation risk was predicted to be > 10% for women diagnosed below approximately 50 years.
Conclusions
Based on the general understanding that a heterozygous mutation probability of 10% or greater justifies gBRCA mutation screening, women with TNBC diagnosed before the age of 50 years and no familial history of breast and ovarian cancer should be tested for gBRCA mutations. In Germany, this would concern approximately 880 women with newly diagnosed TNBC per year, of whom approximately 150 are expected to be identified as carriers of a pathogenic gBRCA mutation.
Journal Article
Copy Number Variants in Patients with Severe Oligozoospermia and Sertoli-Cell-Only Syndrome
2011
A genetic origin is estimated in 30% of infertile men with the common phenotypes of oligo- or azoospermia, but the pathogenesis of spermatogenic failure remains frequently obscure. To determine the involvement of Copy Number Variants (CNVs) in the origin of male infertility, patients with idiopathic severe oligozoospermia (N = 89), Sertoli-cell-only syndrome (SCOS, N = 37)) and controls with normozoospermia (N = 100) were analysed by array-CGH using the 244A/400K array sets (Agilent Technologies). The mean number of CNVs and the amount of DNA gain/loss were comparable between all groups. Ten recurring CNVs were only found in patients with severe oligozoospermia, three only in SCOS and one CNV in both groups with spermatogenic failure but not in normozoospermic men. Sex-chromosomal, mostly private CNVs were significantly overrepresented in patients with SCOS. CNVs found several times in all groups were analysed in a case-control design and four additional candidate genes and two regions without known genes were associated with SCOS (P<1×10(-3)). In conclusion, by applying array-CGH to study male infertility for the first time, we provide a number of candidate genes possibly causing or being risk factors for the men's spermatogenic failure. The recurring, patient-specific and private, sex-chromosomal CNVs as well as those associated with SCOS are candidates for further, larger case-control and re-sequencing studies.
Journal Article
Comprehensive sequence analysis of the NR5A1 gene encoding steroidogenic factor 1 in a large group of infertile males
by
Gromoll, Jörg
,
Wieacker, Peter
,
Tewes, Ann-Christin
in
Amino Acid Sequence
,
Deoxyribonucleic acid
,
DNA Mutational Analysis
2013
The steroidogenic factor 1 (SF1) protein, encoded by the NR5A1 gene, plays a central role in gonadal development and steroidogenesis. Mutations in NR5A1 were first described in patients with primary adrenal insufficiency and 46,XY disorders of sexual development and later also in men with hypospadias, bilateral anorchia and micropenis and women with primary ovarian insufficiency. Recently, heterozygous missense mutations were found in 4% of infertile men with unexplained reduced sperm counts living in France, but all mutation carriers were of non-Caucasian ancestry. Therefore, we performed a comprehensive NR5A1 sequence analysis in 488 well-characterised predominantly Caucasian patients with azoo- or severe oligozoospermia. Two-hundred-thirty-seven men with normal semen parameters were sequenced as controls. In addition to several synonymous variants of unclear pathogenicity, three heterozygous missense mutations predicted to be damaging to SF1 protein function were identified. The andrological phenotype in infertile but otherwise healthy mutation carriers seems variable. In conclusion, mutations altering SF1 protein function and causing spermatogenic failure are also found in men of German origin, but the prevalence seems markedly lower than in other populations.
Journal Article
Gerodermia osteodysplastica is caused by mutations in SCYL1BP1, a Rab-6 interacting golgin
by
Newman, William
,
Wieacker, Peter
,
Rajab, Anna
in
Agriculture
,
Animal Genetics and Genomics
,
Biological and medical sciences
2008
Stefan Mundlos and colleagues report the identification of mutations in
SCYL1BP1
in families with gerodermia osteodysplastica, a disorder characterized by wrinkly skin and osteoporosis. SCYL1BP1 localizes to the Golgi apparatus and interacts with Rab6.
Gerodermia osteodysplastica is an autosomal recessive disorder characterized by wrinkly skin and osteoporosis. Here we demonstrate that gerodermia osteodysplastica is caused by loss-of-function mutations in
SCYL1BP1
, which is highly expressed in skin and osteoblasts. The protein localizes to the Golgi apparatus and interacts with Rab6, identifying SCYL1BP1 as a golgin. These results associate abnormalities of the secretory pathway with age-related changes in connective tissues.
Journal Article
Dissecting the molecular mechanisms in craniofrontonasal syndrome: differential mRNA expression of mutant EFNB1 and the cellular mosaic
by
Reardon, William
,
Wieacker, Peter
,
Wieland, Ilse
in
Adult
,
Amino Acid Sequence
,
Base Sequence
2008
Craniofrontonasal syndrome (CFNS) is an X-linked malformation syndrome with variable phenotype that is caused by mutations in the ephrin-B1 gene (
EFNB1
). Over 50% of
EFNB1
mutations result in premature termination codons that may elicit mRNA degradation by the nonsense-mediated decay pathway. To assess the effects of various mutations at the transcript level, expression of
EFNB1
mRNA was studied by RT-PCR in fibroblast cultures established from CFNS female patients. Compared to the wild-type and two missense mutation alleles, severe depletion of transcripts was observed for mutant alleles harbouring either splice site mutation c.407-2A>T at the exon 2/3 boundary or frameshift mutation c.377_384delTCAAGAAG in exon 2. In contrast, escape from mRNA decay was observed for mutation c.614_615delCT, which generates a premature termination codon close to the 3′-end of the penultimate exon 4 disobeying the ‘50–55 bp’ rule. These results suggest differential degradation of mutant
EFNB1
transcripts by the nonsense-mediated mRNA decay pathway. Although the clinical phenotypes of the patients were not highly suggestive of a phenotype–genotype correlation, the two female patients were diagnosed with diaphragmatic hernia harbouring putative ephrin-B1 truncating mutations. Previously, disease manifestation in heterozygous females had been attributed mainly to cellular interference of divergent cell populations expressing wild-type or mutant
EFNB1
, depending on the pattern of X-inactivation. Upon clonal expansion of patient cells with either the wild-type or mutant
EFNB1
on the active X-chromosome, we were able to separate mutant and wild-type
EFNB1
-expressing cells
in vitro
, further supporting the concept of cellular interference in CFNS.
Journal Article
Promoter CpG hypermethylation and downregulation of DICE1 expression in prostate cancer
2005
A critical region of loss of heterozygosity on human chromosome 13q14 harbors the tumor suppressor gene
DICE1
(
DDX26
). To elucidate the reduced
DICE1
expression in tumor cells, the putative promoter sequence upstream of the
DICE1
gene was analysed. This sequence shows a high GC content and is rich in CpG sites and binding sites of transcriptional factors. Promoter activity was identified within three overlapping fragments of the 800 bp sequence upstream of the
DICE1
gene. A 13 bp deletion polymorphism detected in the
DICE1
promoter region showed a decreased activity compared with the undeleted variant. However, this 13 bp deletion was seen in male control samples and patients with prostate cancer or benign prostatic hyperplasia at similar rates. A reduced
DICE1
expression was observed in prostate cancer cell lines DU145 and LNCaP. This downregulation is associated with hypermethylation of the
DICE1
promoter. Treatment of both prostate cancer cell lines with 5-azacytidine leads to upregulation of
DICE1
expression. Hypermethylation of CpG sites of the
DICE1
promoter was observed in four of eight analysed prostate cancers. This study suggests that transcriptional repression of
DICE1
is caused by hypermethylation of the
DICE1
promoter region in prostate cancer cells.
Journal Article
The impact of CFNS-causing EFNB1 mutations on ephrin-B1 function
by
Gucev, Zoran
,
Makarov, Roman
,
Steiner, Bernhard
in
Biomedical and Life Sciences
,
Biomedicine
,
Cell culture
2010
Background
Mutations of
EFNB1
cause the X-linked malformation syndrome craniofrontonasal syndrome (CFNS). CFNS is characterized by an unusual phenotypic pattern of inheritance, because it affects heterozygous females more severely than hemizygous males. This sex-dependent inheritance has been explained by random X-inactivation in heterozygous females and the consequences of cellular interference of wild type and mutant
EFNB1
-expressing cell populations.
EFNB1
encodes the transmembrane protein ephrin-B1, that forms bi-directional signalling complexes with Eph receptor tyrosine kinases expressed on complementary cells. Here, we studied the effects of patient-derived
EFNB1
mutations predicted to give rise to truncated ephrin-B1 protein or to disturb Eph/ephrin-B1 reverse ephrin-B1 signalling. Five mutations are investigated in this work: nonsense mutation c.196C > T/p.R66X, frameshift mutation c.614_615delCT, splice-site mutation c.406 + 2T > C and two missense mutations p.P54L and p.T111I. Both missense mutations are located in the extracellular ephrin domain involved in Eph-ephrin-B1 recognition and higher order complex formation.
Methods
Nonsense mutation c.196C > T/p.R66X, frameshift mutation c.614_615delCT and splice-site mutation c.406+2T > C were detected in the primary patient fibroblasts by direct sequencing of the DNA and were further analysed by RT-PCR and Western blot analyses.
The impact of missense mutations p.P54L and p.T111I on cell behaviour and reverse ephrin-B1 cell signalling was analysed in a cell culture model using NIH 3T3 fibroblasts. These cells were transfected with the constructs generated by
in vitro
site-directed mutagenesis. Investigation of missense mutations was performed using the Western blot analysis and time-lapse microscopy.
Results and Discussion
Nonsense mutation c.196C > T/p.R66X and frameshift mutation c.614_615delCT escape nonsense-mediated RNA decay (NMD), splice-site mutation c.406+2T > C results in either retention of intron 2 or activation of a cryptic splice site in exon 2. However, c.614_615delCT and c.406+2T > C mutations were found to be not compatible with production of a soluble ephrin-B1 protein. Protein expression of the p.R66X mutation was predicted unlikely but has not been investigated.
Ectopic expression of p.P54L ephrin-B1 resists Eph-receptor mediated cell cluster formation in tissue culture and intracellular ephrin-B1 Tyr324 and Tyr329 phosphorylation. Cells expressing p.T111I protein show similar responses as wild type expressing cells, however, phosphorylation of Tyr324 and Tyr329 is reduced.
Conclusions
Pathogenic mechanisms in CFNS manifestation include impaired ephrin-B1 signalling combined with cellular interference.
Journal Article
High amount of fertility reducing tumors and procedures, but no evidence for premature ovarian failure in female Lynch syndrome patients
by
Wieacker, Peter
,
Steinke-Lange, Verena
,
Knapp, Michael
in
Cancer
,
Colorectal cancer
,
Fertility
2024
Lynch syndrome (LS; HNPCC) patients carry heterozygous pathogenic germline variants in mismatch repair (MMR) genes, which have also been shown to play an important role in meiosis. Therefore, it was hypothesized, that LS might be associated with a higher risk for premature ovarian failure (POF) or earlier menopause. Data on medical gynaecological history, cancer diagnoses and therapy were collected from 167 female LS patients and compared to a population-based control cohort. There was no difference between the age of menopause in patients compared to controls and no evidence for a higher risk of POF in LS patients. However, around one third (35%) of the probands have already had premenopausal cancer and mostly cancer-related treatment affecting fertility before the age of 45 years. Therefore, childbearing time might still be limited in these patients, especially due to the premenopausal cancer risk. LS patients should be informed in time about the elevated premenopausal cancer risks and the possible impact on family planning. This is particularly relevant since the average childbearing age has increased during the last decades.
Journal Article
Copy number variation of two separate regulatory regions upstream of SOX9 causes isolated 46,XY or 46,XX disorder of sex development
2015
Background SOX9 mutations cause the skeletal malformation syndrome campomelic dysplasia in combination with XY sex reversal. Studies in mice indicate that SOX9 acts as a testis-inducing transcription factor downstream of SRY, triggering Sertoli cell and testis differentiation. An SRY-dependent testis-specific enhancer for Sox9 has been identified only in mice. A previous study has implicated copy number variations (CNVs) of a 78 kb region 517–595 kb upstream of SOX9 in the aetiology of both 46,XY and 46,XX disorders of sex development (DSD). We wanted to better define this region for both disorders. Results By CNV analysis, we identified SOX9 upstream duplications in three cases of SRY-negative 46,XX DSD, which together with previously reported duplications define a 68 kb region, 516–584 kb upstream of SOX9, designated XXSR (XX sex reversal region). More importantly, we identified heterozygous deletions in four families with SRY-positive 46,XY DSD without skeletal phenotype, which define a 32.5 kb interval 607.1–639.6 kb upstream of SOX9, designated XY sex reversal region (XYSR). To localise the suspected testis-specific enhancer, XYSR subfragments were tested in cell transfection and transgenic experiments. While transgenic experiments remained inconclusive, a 1.9 kb SRY-responsive subfragment drove expression specifically in Sertoli-like cells. Conclusions Our results indicate that isolated 46,XY and 46,XX DSD can be assigned to two separate regulatory regions, XYSR and XXSR, far upstream of SOX9. The 1.9 kb SRY-responsive subfragment from the XYSR might constitute the core of the Sertoli-cell enhancer of human SOX9, representing the so far missing link in the genetic cascade of male sex determination.
Journal Article