Pathogenic variants in E3 ubiquitin ligase RLIM/RNF12 lead to a syndromic X-linked intellectual disability and behavior disorder.

RLIM, also known as RNF12, is an X-linked E3 ubiquitin ligase acting as a negative regulator of LIM-domain containing transcription factors and participates in X-chromosome inactivation (XCI) in mice. We report the genetic and clinical findings of 84 individuals from nine unrelated families, eight of whom who have pathogenic variants in RLIM (RING finger LIM domain-interacting protein). A total of 40 affected males have X-linked intellectual disability (XLID) and variable behavioral anomalies with or without congenital malformations. In contrast, 44 heterozygous female carriers have normal cognition and behavior, but eight showed mild physical features. All RLIM variants identified are missense changes co-segregating with the phenotype and predicted to affect protein function. Eight of the nine altered amino acids are conserved and lie either within a domain essential for binding interacting proteins or in the C-terminal RING finger catalytic domain. In vitro experiments revealed that these amino acid changes in the RLIM RING finger impaired RLIM ubiquitin ligase activity. In vivo experiments in rlim mutant zebrafish showed that wild type RLIM rescued the zebrafish rlim phenotype, whereas the patient-specific missense RLIM variants failed to rescue the phenotype and thus represent likely severe loss-of-function mutations. In summary, we identified a spectrum of RLIM missense variants causing syndromic XLID and affecting the ubiquitin ligase activity of RLIM, suggesting that enzymatic activity of RLIM is required for normal development, cognition and behavior.

Deleterious de novo variants of X-linked ZC4H2 in females cause a variable phenotype with neurogenic arthrogryposis multiplex congenita.

Pathogenic variants in the X-linked gene ZC4H2, which encodes a zinc-finger protein, cause an infrequently described syndromic form of arthrogryposis multiplex congenita (AMC) with central and peripheral nervous system involvement. We present genetic and detailed phenotypic information on 23 newly identified families and simplex cases that include 19 affected females from 18 families and 14 affected males from nine families. Of note, the 15 females with deleterious de novo ZC4H2 variants presented with phenotypes ranging from mild to severe, and their clinical features overlapped with those seen in affected males. By contrast, of the nine carrier females with inherited ZC4H2 missense variants that were deleterious in affected male relatives, four were symptomatic. We also compared clinical phenotypes with previously published cases of both sexes and provide an overview on 48 males and 57 females from 42 families. The spectrum of ZC4H2 defects comprises novel and recurrent mostly inherited missense variants in affected males, and de novo splicing, frameshift, nonsense, and partial ZC4H2 deletions in affected females. Pathogenicity of two newly identified missense variants was further supported by studies in zebrafish. We propose ZC4H2 as a good candidate for early genetic testing of males and females with a clinical suspicion of fetal hypo-/akinesia and/or (neurogenic) AMC.

Neurophysiology versus clinical genetics in Rett syndrome: A multicenter study.

Many studies have attempted to establish the genotype-phenotype correlation in Rett syndrome (RTT). Cardiorespiratory measurements provide robust objective data, to correlate with each of the different clinical phenotypes. It has important implications for the management and treatment of this syndrome. The aim of this study was to correlate the genotype with the quantitative cardiorespiratory data obtained by neurophysiological measurement combined with a clinical severity score. This international multicenter study was conducted in four European countries from 1999 to 2012. The study cohort consisted of a group of 132 well-defined RTT females aged between 2 and 43 years with extended clinical, molecular, and neurophysiological assessments. Diagnosis of RTT was based on the consensus criteria for RTT and molecular confirmation. Genotype-phenotype analyses of clinical features and cardiorespiratory data were performed after grouping mutations by the same type and localization or having the same putative biological effect on the MeCP2 protein, and subsequently on eight single recurrent mutations. A less severe phenotype was seen in females with CTS, p.R133C, and p.R294X mutations. Autonomic disturbances were present in all females, and not restricted to nor influenced by one specific group or any single recurrent mutation. The objective information from non-invasive neurophysiological evaluation of the disturbed central autonomic control is of great importance in helping to organize the lifelong care for females with RTT. Further research is needed to provide insights into the pathogenesis of autonomic dysfunction, and to develop evidence-based management in RTT. © 2016 Wiley Periodicals, Inc.

Common genetic variants and modification of penetrance of BRCA2-associated breast cancer.

The considerable uncertainty regarding cancer risks associated with inherited mutations of BRCA2 is due to unknown factors. To investigate whether common genetic variants modify penetrance for BRCA2 mutation carriers, we undertook a two-staged genome-wide association study in BRCA2 mutation carriers. In stage 1 using the Affymetrix 6.0 platform, 592,163 filtered SNPs genotyped were available on 899 young (<40 years) affected and 804 unaffected carriers of European ancestry. Associations were evaluated using a survival-based score test adjusted for familial correlations and stratified by country of the study and BRCA2*6174delT mutation status. The genomic inflation factor (λ) was 1.011. The stage 1 association analysis revealed multiple variants associated with breast cancer risk: 3 SNPs had p-values<10(-5) and 39 SNPs had p-values<10(-4). These variants included several previously associated with sporadic breast cancer risk and two novel loci on chromosome 20 (rs311499) and chromosome 10 (rs16917302). The chromosome 10 locus was in ZNF365, which contains another variant that has recently been associated with breast cancer in an independent study of unselected cases. In stage 2, the top 85 loci from stage 1 were genotyped in 1,264 cases and 1,222 controls. Hazard ratios (HR) and 95% confidence intervals (CI) for stage 1 and 2 were combined and estimated using a retrospective likelihood approach, stratified by country of residence and the most common mutation, BRCA2*6174delT. The combined per allele HR of the minor allele for the novel loci rs16917302 was 0.75 (95% CI 0.66-0.86, ) and for rs311499 was 0.72 (95% CI 0.61-0.85, ). FGFR2 rs2981575 had the strongest association with breast cancer risk (per allele HR = 1.28, 95% CI 1.18-1.39, ). These results indicate that SNPs that modify BRCA2 penetrance identified by an agnostic approach thus far are limited to variants that also modify risk of sporadic BRCA2 wild-type breast cancer.

Genotype-phenotype relationships as prognosticators in Rett syndrome should be handled with care in clinical practice.

Rett syndrome (RTT; OMIM 312750) is an X-linked dominant neurodevelopmental disorder leading to cognitive and motor impairment, epilepsy, and autonomic dysfunction in females. Since the discovery that RTT is caused by mutations in MECP2, large retrospective genotype-phenotype correlation studies have been performed. A number of general genotype-phenotype relationships were confirmed and specific disorder profiles were described. Nevertheless, conflicting results are still under discussion, partly due to the variability in classification of mutations, assessment tools, and structure of the data sets. The aim of this study was to investigate relationships between genotype and specific clinical data collected by the same experienced physician in a well-documented RTT cohort, and evaluate its prognostic value in counseling young parents with a newly diagnosed RTT girl regarding her future outcome. The Maastricht-Leuven Rett Syndrome Database is a register of 137 molecularly confirmed clinical RTT cases, containing both molecular and clinical data on examination and follow up by the same experienced physician. Although the general genotype-phenotype relationships were confirmed, the clinical severity was still found to be very variable. We therefore recommend caution in using genotype-phenotype data in the prognosis of outcome for children in Rett syndrome. Early diagnosis, early intervention, and preventive management are imperative for better outcomes and better quality of daily life for RTT females and their families.

Characterisation of unclassified variants in the BRCA1/2 genes with a putative effect on splicing.

A subset of the unclassified variants (UVs) identified during genetic screening of BRCA1/2 genes may affect splicing. We assessed at RNA level the effect of four BRCA1 and ten BRCA2 UVs with a putative splice effect, as predicted in silico. The variants selected for this study were beyond the positions -1, -2 or +1, +2 from the exon, and were not previously described (n = 8) or their effect on splicing was not assessed previously (n = 6). Lymphocytes from UV carriers and healthy controls were cultured and treated with puromycin to prevent nonsense-mediated mRNA decay. The relative contribution of each allele to the various transcripts was assessed using combinations of allele-specific and transcript-specific primers. BRCA2 c.425G>T, c.7976+3_7976+4del and c.8754+3G>C give rise to aberrant transcripts BRCA2Δ4, BRCA2Δ17 and retention of 46nt of intron 21, respectively, and were considered pathogenic. BRCA1 c.4987-3C>G gives rise to BRCA1Δ17 that is likely pathogenic; however, residual expression of the full-length transcript from the variant allele could not be excluded. BRCA1 c.692C>T, c.693G>A and BRCA2 c.6935A>T, besides expressing the full-length transcript, increased expression of BRCA1Δ11 and BRCA2Δ12, respectively. As these are naturally occurring isoforms, also observed in controls, the clinical relevance is unclear. The seven remaining UVs did not affect splicing and three intronic variants were therefore classified as neutral. In conclusion, the RNA analysis results clarified the clinical relevance of 6 of the 14 studied UVs and thereby greatly improve the genetic counselling of high-risk breast/ovarian cancer patients carrying these classified variants.

Further characterization of the first seminoma cell line TCam-2.

Testicular germ cell tumors of adolescents and adults (TGCTs) can be classified into seminomatous and nonseminomatous tumors. Various nonseminomatous cell lines, predominantly embryonal carcinoma, have been established and proven to be valuable for pathobiological and clinical studies. So far, no cell lines have been derived from seminoma which constitutes more than 50% of invasive TGCTs. Such a cell line is essential for experimental investigation of biological characteristics of the cell of origin of TGCTs, i.e., carcinoma in situ of the testis, which shows characteristics of a seminoma cell. Before a cell line can be used as model, it must be verified regarding its origin and characteristics. Therefore, a multidisciplinary approach was undertaken on TCam-2 cells, supposedly the first seminoma cell line. Fluorescence in situ hybridization, array comparative genomic hybridization, and spectral karyotyping demonstrated an aneuploid DNA content, with gain of 12p, characteristic for TGCTs. Genome wide mRNA and microRNA expression profiling supported the seminoma origin, in line with the biallelic expression of imprinted genes IGF2/H19 and associated demethylation of the imprinting control region. Moreover, the presence of specific markers, demonstrated by immunohistochemistry, including (wild type) KIT, stem cell factor, placental alkaline phosphatase, OCT3/4 (also demonstrated by a specific Q-PCR) and NANOG, and the absence of CD30, SSX2-4, and SOX2, confirms that TCam-2 is a seminoma cell line. Although mutations in oncogenes and tumor suppressor genes are rather rare in TGCTs, TCam-2 had a mutated BRAF gene (V600E), which likely explains the fact that these cells could be propagated in vitro. In conclusion, TCam-2 is the first well-characterized seminoma-derived cell line, with an exceptional mutation, rarely found in TGCTs.

MCT8 mutation analysis and identification of the first female with Allan-Herndon-Dudley syndrome due to loss of MCT8 expression.

Mutations in the thyroid monocarboxylate transporter 8 gene (MCT8/SLC16A2) have been reported to result in X-linked mental retardation (XLMR) in patients with clinical features of the Allan-Herndon-Dudley syndrome (AHDS). We performed MCT8 mutation analysis including 13 XLMR families with LOD scores >2.0, 401 male MR sibships and 47 sporadic male patients with AHDS-like clinical features. One nonsense mutation (c.629insA) and two missense changes (c.1A>T and c.1673G>A) were identified. Consistent with previous reports on MCT8 missense changes, the patient with c.1673G>A showed elevated serum T3 level. The c.1A>T change in another patient affects a putative translation start codon, but the same change was present in his healthy brother. In addition normal serum T3 levels were present, suggesting that the c.1A>T (NM_006517) variation is not responsible for the MR phenotype but indicates that MCT8 translation likely starts with a methionine at position p.75. Moreover, we characterized a de novo translocation t(X;9)(q13.2;p24) in a female patient with full blown AHDS clinical features including elevated serum T3 levels. The MCT8 gene was disrupted at the X-breakpoint. A complete loss of MCT8 expression was observed in a fibroblast cell-line derived from this patient because of unfavorable nonrandom X-inactivation. Taken together, these data indicate that MCT8 mutations are not common in non-AHDS MR patients yet they support that elevated serum T3 levels can be indicative for AHDS and that AHDS clinical features can be present in female MCT8 mutation carriers whenever there is unfavorable nonrandom X-inactivation.

The association between cancer family history and ovarian cancer risk in BRCA1/2 mutation carriers: can it be explained by the mutation position?

This observational study aimed to investigate whether the reported association between family history (FH) of breast cancer (BC) or ovarian cancer (OC) and OC risks in BRCA1/2 mutation carriers can be explained by mutation position on the gene. In total, 3310 female BRCA1/2 mutation carriers participating in a nationwide prospective cohort (Hereditary Breast and Ovarian Cancer in the Netherlands) were included. FH was classified according to cancer occurrence in first-degree relatives (BC only, OC only, both, neither) and mutations were classified according to their position on the gene (OC cluster region (OCCR), BC cluster region, neither). The main outcome was OC occurrence. Cox proportional-hazard models were applied to investigate the association between FH and OC risks before and after adjusting for mutation position. Of all women included, 202 were diagnosed with OC. A BC-only FH tended to be associated with lower OC risks when compared with a FH without BC/OC (HR: 0.79, 95% CI: 0.52-1.17; HR: 0.59, 95% CI: 0.33-1.07 for BRCA1 and BRCA2, respectively) while an OC-only FH tended to be associated with higher risks (HR: 1.58, 95% CI: 0.90-2.77; HR: 1.75, 95% CI: 0.70-4.37 for BRCA1 and BRCA2, respectively). After adjusting for mutation position, association between FH and OC risks was slightly smaller in magnitude (HR: 0.85, 95% CI: 0.55-1.30; HR: 0.64, 95% CI: 0.34-1.21 for BC-only FH in BRCA1 and BRCA2, respectively; HR: 1.46, 95% CI: 0.80-2.68; HR: 1.49, 95% CI: 0.44-4.02 for OC-only FH in BRCA1 and BRCA2, respectively), indicating that mutation position explains only part of the association. Considering the magnitude of the observed trend, we do not believe FH should be used to change counseling regarding OC prevention.

MECP2 mutations are an infrequent cause of mental retardation associated with neurological problems in male patients.

Mutations in the methyl-CpG-binding protein 2 (MECP2) gene located on Xq28, cause Rett syndrome (RTT) in female patients. Meanwhile, nonmosaic MECP2 mutations unknown in girls have been found in an increasing number of male patients with a normal 46, XY karyotype. They can cause a broad spectrum of neurodevelopmental disorders which often show a combination of mental retardation (MR) with neurological symptoms. We present the results of MECP2 analysis in a group of 72 male patients with an unexplained combination of MR and neurological features, and review the mutational reports published on male patients since the discovery of the MECP2 gene. Analysis included sequencing of exon 1 which thus far was mostly omitted from DNA screening. One pathogenic mutation has been found in a patient with Rett variant, in addition to an unclassified variant and a series of nonpathogenic changes. No changes have been found in exon 1. Criteria for testing of male patients are classic RTT, severe neonatal encephalopathy, and RTT variant which may be clinically underrecognized. Testing can also be considered in males with a combination of unexplained MR and (progressive) neurological manifestations although the yield of MECP2 analysis is probably low in this situation. Based on the literature, MECP2 testing in males with MR only is debatable.

POU5F1 (OCT3/4) identifies cells with pluripotent potential in human germ cell tumors.

Human germ cell tumors (GCTs) may have variable histology and clinical behavior, depending on factors such as sex of the patient, age at clinical diagnosis, and anatomical site of the tumor. Some types of GCT, i.e., the seminomas/germinomas/dysgerminomas and embryonal carcinomas (the stem cell component of nonseminomas), have pluripotent potential, which is demonstrated by their capacity to differentiate into somatic and/or extraembryonic elements. Although embryonal carcinoma cells are intrinsically pluripotent, seminoma/germinoma/dysgerminoma cells, as well as their precursor carcinoma in situ/gonadoblastoma cells, have the phenotype of early germ cells that can be activated to pluripotency. The other types of GCT (teratomas and yolk sac tumors of infants and newborn, dermoid cyst of the ovary, and spermatocytic seminoma of elderly) are composed of (fully) differentiated tissues and lack the appearance of undifferentiated and pluripotent stem cells. OCT3/4, a transcription factor also known as OTF3 and POU5F1, is involved in regulation of pluripotency during normal development and is detectable in embryonic stem and germ cells. We analyzed the presence of POU5F1 in GCT and other tumor types using immunohistochemistry. The protein was consistently detected in carcinoma in situ/gonadoblastoma, seminomas/germinoma/dysgerminoma, and embryonal carcinoma but not in the various types of differentiated nonseminomas. Multitumor tissue microarray analysis covering >100 different tumor categories and 3600 individual cancers verified that POU5F1 expression is specific for particular subtypes of GCT of adults. No protein was observed in GCT of newborn and infants, spermatocytic seminomas, and the various tumors of nongerm cell origin. In addition, no difference in staining pattern was found in chemosensitive and chemoresistant GCT of adults. These results indicate preservation of the link between POU5F1 and pluripotency, as reported during normal development, after malignant transformation. Therefore, POU5F1 immunohistochemistry is an informative diagnostic tool for pluripotent GCT and offers new insights into the histological heterogeneity of this cancer.

Truncating de novo mutations in the Krüppel-type zinc-finger gene ZNF148 in patients with corpus callosum defects, developmental delay, short stature, and dysmorphisms.

BACKGROUND: Krüppel-type zinc finger genes (ZNF) constitute a large yet relatively poorly characterized gene family. ZNF genes encode proteins that recognize specific DNA motifs in gene promotors. They act as transcriptional co-activators or -repressors via interaction with chromatin remodeling proteins and other transcription factors. Only few ZNF genes are currently linked to human disorders and identification of ZNF gene-associated human diseases may help understand their function. Here we provide genetic, statistical, and clinical evidence to support association of ZNF148 with a new intellectual disability (ID) syndrome disorder. METHODS: Routine diagnostic exome sequencing data were obtained from 2172 patients with ID and/or multiple congenital anomalies. RESULTS: In a cohort of 2172 patient-parent trios referred for routine diagnostic whole exome sequencing for ID and/or multiple congenital anomalies (MCA) in the period 2012-2016, four patients were identified who carried de novo heterozygous nonsense or frameshift mutations in the ZNF148 gene. This was the only ZNF gene with recurrent truncating de novo mutations in this cohort. All mutations resulted in premature termination codons in the last exon of ZNF148. The number of the de novo truncating mutations in the ZNF148 gene was significantly enriched (p = 5.42 × 10-3). The newly described ZNF148-associated syndrome is characterized by underdevelopment of the corpus callosum, mild to moderate developmental delay and ID, variable microcephaly or mild macrocephaly, short stature, feeding problems, facial dysmorphisms, and cardiac and renal malformations. CONCLUSIONS: We propose ZNF148 as a gene involved in a newly described ID syndrome with a recurrent phenotype and postulate that the ZNF148 is a hitherto unrecognized but crucial transcription factor in the development of the corpus callosum. Our study illustrates the advantage of whole exome sequencing in a large cohort using a parent-offspring trio approach for identifying novel genes involved in rare human diseases.

Neurodevelopmental disorders in males related to the gene causing Rett syndrome in females (MECP2).

Mutations in the MECP2 (methyl-CpG-binding protein 2) gene are known to cause Rett syndrome, a well-known and clinically defined neurodevelopmental disorder. Rett syndrome occurs almost exclusively in females and for a long time was thought to be an X-linked dominant condition lethal in hemizygous males. Since the discovery of the MECP2 gene as the cause of Rett syndrome in 1999, MECP2 mutations have, however, also been reported in males. These males phenotypically have classical Rett syndrome when the mutation arises as somatic mosaicism or when they have an extra X chromosome. In all other cases, males with MECP2 mutations show diverse phenotypes different from classical Rett syndrome. The spectrum ranges from severe congenital encephalopathy, mental retardation with various neurological symptoms, occasionally in association with psychiatric illness, to mild mental retardation only. We present a 21-year-old male with severe mental retardation, spastic tetraplegia, dystonia, apraxia and neurogenic scoliosis. A history of early hypotonia evolving into severe spasticity, slowing of head growth, breathing irregularities and good visual interactive behaviour were highly suggestive of Rett syndrome. He has a de novo missense mutation in exon 3 of the MECP2 gene (P225L). The clinical spectrum and molecular findings in males with MECP2 mutations are reviewed.

Psychiatric illness in a cohort of adults with Prader-Willi syndrome.

Previous studies have suggested an association between PWS and comorbid psychiatric illness. Data on prevalence rates of psychopathology is still scarce. This paper describes a large-scale, systematic study investigating the prevalence of psychiatric illness in a Dutch adult PWS cohort. One hundred and two individuals were screened for psychiatric illness. Case vignettes were written by the first author on 63 individuals with a positive screening on psychopathology according to the interviews, medical history, medication use and behavioural questionnaires. These case vignettes were rated by two psychiatrists specializing in intellectual disability (ID). Psychopathology was divided into four diagnostic categories: bipolar disorder with psychotic symptoms, psychotic illness, depressive illness with psychotic symptoms and depressive illness without psychotic symptoms. Nine out of 53 persons (17%) with a 15q11-13 deletion and 28 out of 44 (64%) persons with maternal uniparental disomy (mUPD) were diagnosed with a current or previous psychiatric illness. Depressive illness with psychotic symptoms was the cause of psychiatric problems in the majority of persons with PWS due to deletion (56%). In the case of mUPD, almost all individuals with histories of psychopathology suffered from psychotic symptoms (85%) with or without affective component. Psychiatric examination should be part of general management of adults with PWS, especially when caused by mUPD. More attention should be paid to the presence of precursor symptoms, indicating a developing psychiatric episode. Longitudinal studies are needed to gain more insight into the natural history of psychiatric illness in adults with PWS.

Different distribution of the genetic subtypes of the Prader-Willi syndrome in the elderly.

The Prader-Willi syndrome (PWS) is a genetic disorder caused by the absent expression of the paternal copy of maternally imprinted genes in chromosome region 15q11-13. The frequencies of different subtypes in PWS are usually given in literature as 70% deletion, 25-30% maternal uniparental disomy (mUPD) and 3-5% others (imprinting centre (IC) defects and translocations). Little is known about factors that influence the frequency of genetic subtypes in PWS. The study sample comprised 102 adults with clinically and genetically confirmed PWS, contacted through the Dutch Prader-Willi Parent Association and through physicians specialized in treating persons with intellectual disabilities. Genetic testing showed 55 persons (54%) with a paternal deletion, 44 persons (43%) with an mUPD and 3 persons (3%) with a defect of the IC. The observed distribution in our study differed from that in literature (70% deletion, 30% mUPD), which was statistically significant (z-score: P<0.05). This was mainly caused by a higher proportion of mUPD in the advanced age groups. Differences in maternal age and BMI of persons with PWS could not explain the differences in distribution across the age groups. Our study population had a much broader age range, compared with other studies, because of a predominance of elderly people (40+ years) with PWS. In other studies, these elderly persons might have been undiagnosed and/or underreported because of a lack of genetic diagnosis. The results underline both the need for correct genetic diagnosis in all persons with PWS and adjustment of the guidelines for preventive management in adulthood.

Expression of the PDGF alpha-receptor 1.5 kb transcript, OCT-4, and c-KIT in human normal and malignant tissues. Implications for the early diagnosis of testicular germ cell tumours and for our understanding of regulatory mechanisms.

Human testicular germ cell tumours of adolescents and adults (TGCTs), including their precursor lesion carcinoma in situ (CIS), show expression of a 1.5 kb alternative transcript of the platelet-derived growth factor (PDGF) alpha-receptor gene. The so-called P2 promoter involved is located in intron 12 and its activity was found to be mutually exclusive with activity of the classical promoter (P1), which encodes the full-length receptor. The presence of the 1.5 kb transcript could be a putative marker for the early molecular diagnosis of TGCTs. In order to validate the RT-PCR approach, this study shows that not more than 100 transcripts are necessary to obtain positivity in the test used; moreover, samples from TGCTs or CIS-containing tissues can be diluted many-fold before resulting in false-negative findings. This study also shows that within TGCTs, as in TGCT-derived cell lines, expression of the 1.5 kb transcript is differentiation-dependent and positively correlated with expression of the embryonic transcription factor OCT-4/POU5F1. Furthermore, the results indicate that in some non-TGCT cancers and cell lines the 1.5 kb transcript is also expressed, but without concomitant OCT-4/POU5F1 expression. The 1.5 kb transcript is also present in early B cells and derived leukaemias (B-ALL). In spite of similarities in chromosomal location, down-regulation upon differentiation of TGCTs, and PDGF alpha-receptor and c-KIT (the stem cell factor receptor) both being a tyrosine kinase receptor, no correlation was found between activity of the P2 promoter of the PDGF alpha-receptor gene and expression of c-KIT. In conclusion, the 1.5 kb transcript of the PDGF alpha-receptor is expressed in various cells and tissues, including particular blood cells. Although this may hamper the use of this transcript as a marker for malignancies in general, it does not appear to interfere with assays for the early detection of TGCTs.