Childhood-onset systemic lupus erythematosus with trisomy X and the increased risk for bone complications: a case report.

BACKGROUND: Systemic lupus erythematosus is a multi-organ inflammatory autoimmune disease; immune complexes are part of the pathogenesis, but not entirely responsible. Trisomy X is the most common female chromosomal abnormality and the role of an additional X chromosome in the development of systemic lupus erythematosus is well recognized. However, the potential complications and optimal management of childhood lupus with trisomy X remain unclear. Herein, we describe a case of childhood-onset systemic lupus erythematosus associated with severe bone complications presumably secondary to trisomy X. CASE PRESENTATION: A 16-year-old Japanese girl was diagnosed with childhood-onset systemic lupus erythematosus and trisomy X. A chromosomal abnormality (47, XXX) was incidentally identified on bone marrow examination initially done to determine the cause of pancytopenia. She had a persistent headache, fever　for six days, diffuse hair loss, mucosal ulcers, butterfly eruptions, and palmar erythema. Furthermore, thrombocytopenia, anemia, and erythrocyte fragmentation were detected, suggesting secondary thrombotic microangiopathy. She was initially treated with intravenous methylprednisolone pulse therapy and prescribed monthly cyclophosphamide for severe disease activity, prednisolone, mycophenolate mofetil, and hydroxychloroquine as remission maintenance drugs. She developed generalized extremity pain that had been worsening throughout the disease. Extremity magnetic resonance imaging performed 12 months after the treatment onset revealed multifocal avascular necrosis, and dual-energy X-ray absorptiometry revealed further decreased bone mineral density. High plasma levels of factor VIII were detected by additional tests for coagulation functions, and we suspected the possibility that factor VIII might cause avascular necrosis due to thrombosis. Currently, she is being treated with prednisolone and MMF for SLE. However, her extremity pain has not been managed effectively even under the administration of non-steroidal anti-inflammatory drugs and pregabalin. CONCLUSIONS: An additional X chromosome has been reported to be associated with factor VIII and osteoporosis. Additionally, elevated plasma levels of FVIII is the risk factors for thrombosis, which leads to the risk of avascular necrosis. Patients with systemic lupus erythematosus complicated by trisomy X might be at a higher risk of avascular necrosis and osteoporosis that can also manifest in childhood systemic lupus erythematosus.

Effect of Y Chromosome Microdeletions on the Pregnancy Outcome of Assisted Reproduction Technology: a Meta-analysis.

This systematic analysis aimed to summarize the effects of Y chromosome microdeletions (YCMs) on pregnancy outcomes of assisted reproductive technology (ART). This retrospective controlled meta-analysis evaluated the effect of YCMs on pregnancy outcomes of ART. Full-text retrieval was conducted in the PubMed, CBM, Web of Science, CNKI, VIP, and WANFANG databases. The pregnancy outcomes included fertilization rate, good embryo rate, clinical pregnancy rate, early miscarriage rate, miscarriage rate, live birth rate, and baby boy rate. The quality of these studies was evaluated using the Newcastle-Ottawa scale. Statistical software Review Manager 5.3 and STATA 14.0 were used. Twelve high-quality studies were included in the analysis. Compared with that in the normal group, the fertilization rate in the YCMs group decreased significantly (odds ratio [OR] = 0.75, 95% confidence interval [CI] [0.63, 0.88], P = 0.0006). However, there was no significant difference (P > 0.05) between groups in the good embryo rate (OR = 0.88, 95% CI [0.72, 1.07]), clinical pregnancy rate (OR = 0.94, 95% CI [0.78, 1.11]), early miscarriage rate (OR = 1.70, 95% CI [0.93, 3.10]), miscarriage rate (OR = 1.3, 95% CI [0.93, 1.91]), live birth rate (OR = 0.90, 95% CI [0.74, 1.08]), and baby boy rate (OR = 1.15, 95% CI [0.85, 1.56]). YCMs are associated with a reduced fertilization rate of ART, but they do not decrease the good embryo rate, clinical pregnancy rate, early miscarriage rate, miscarriage rate, live birth rate, or baby boy rate.

Early neurodevelopmental and medical profile in children with sex chromosome trisomies: Background for the prospective eXtraordinarY babies study to identify early risk factors and targets for intervention.

Sex chromosome trisomies (SCT), including Klinefelter syndrome/XXY, Trisomy X, and XYY syndrome, occur in 1 of every 500 births. The past decades of research have resulted in a broadening of known associated medical comorbidities as well as advances in psychological research. This review summarizes what is known about early neurodevelopmental, behavioral, and medical manifestations in young children with SCT. We focus on recent research and unanswered questions related to the risk for neurodevelopmental disorders that commonly present in the first years of life and discuss the medical and endocrine manifestations of SCT at this young age. The increasing rate of prenatal SCT diagnoses provides the opportunity to address gaps in the existing literature in a new birth cohort, leading to development of the eXtraordinarY Babies Study. This study aims to better describe and compare the natural history of SCT conditions, identify predictors of positive and negative outcomes in SCT, evaluate developmental and autism screening measures commonly used in primary care practices for the SCT population, and build a rich data set linked to a bank of biological samples for future study. Results from this study and ongoing international research efforts will inform evidence-based care and improve health and neurodevelopmental outcomes.

Adaptive functioning in children and adolescents with Trisomy X: An exploratory analysis.

Identifying the factors related to adaptive functioning will improve the information available to families and providers of females with Trisomy X. Cognitive and behavioral features were assessed in 50 females ages 12.2 ± 3.6 years using the Behavior Assessment System for Children Second Edition (BASC-2) and Wechsler Scales of Intelligence. Executive functioning, social skills, and autistic traits were evaluated in a subset. Adaptive functioning was assessed using the BASC-2 adaptive skills composite score (ASC). Participants were classified as average adaptive skills (ASC T-score > 40) or deficits (ASC T-score < 40). Group comparisons were conducted. Multiple linear regression examined which factors contributed to ASC score. Twenty-eight females (55.6%) had adaptive skills deficits with functional communication being the most commonly affected adaptive domain. The group with ASC in the average range had higher verbal IQ (VIQ) and lower rates of numerous behavioral concerns. Internalizing behavior composite, DSM-IV inattentive symptoms score, and VIQ were significant predictors of ASC. Prenatally diagnosed females comprised over 70% of those with average adaptive skills. In this study, internalizing behaviors, inattentive ADHD symptoms, and VIQ were associated with poorer adaptive functioning. Early interventions targeting internalizing behaviors, attention/executive functioning, and communication skills may improve adaptive skills and deserve further study.

The behavioral profile of children aged 1-5 years with sex chromosome trisomy (47,XXX, 47,XXY, 47,XYY).

Children with SCT have an increased risk of suboptimal neurodevelopment. Previous studies have shown an elevated risk for neurobehavioral problems in individuals with SCT. However, not much is known about neurobehavioral problems in very young children; knowledge that could help with early identification of children at risk for suboptimal development, and that could help establish targets for early intervention. This study addressed the question of what the behavioral profile of children with SCT aged 1-5 years looks like. In total, 182 children aged 1-5 years participated in this study (NSCT =87, Nnonclinical controls = 95). Recruitment and assessment took place in the Netherlands and the United States. The SCT group was recruited through prospective follow-up (50%), information seeking parents (31%), and clinical referral (18%). Behavioral profiles were assessed with the child behavior checklist and the ages-and-stages social-emotional questionnaire. Levels of parent-rated problem behavior were higher in children with SCT. Difficulties with overall social-emotional functioning were already present in 1-year-olds, and elevated scores were persistent across the full age range. Affective and pervasive developmental behaviors were seen in late toddlerhood and prominent at preschool age. Anxiety, attention deficit, and oppositional defiant behaviors were seen in preschool-aged children. Within this cross-sectional study, the developmental trajectory of affective, pervasive developmental, and oppositional defiant behaviors seemed to be different for SCT children than nonclinical controls. Collectively, these results demonstrate the importance of behavioral screening for behavioral problems in routine clinical care for children with SCT from a young age. Social-emotional problems may require special attention, as these problems seem most prominent, showing increased risk across the full age range, and with these problems occurring regardless of the timing of diagnosis, and across all three SCT karyotypes.

Motor Development and Health-Related Fitness in Trisomy X: A Case Report.

PURPOSE: This case study provides information regarding the motor development and health-related fitness level of a female with 47,XXX. The Movement Assessment Battery for Children-Second Edition (MABC-2) and the Test of Gross Motor Development-Second Edition (TGMD-2) batteries were used to assess motor competence and gross motor development, respectively. Cardiorespiratory, muscular fitness, and flexibility were assessed by means of field-based tests. Two groups of children developing typically were used for comparison purposes. SUMMARY OF KEY POINTS: Results from the MABC-2 indicated that the participant was placed in the 37th percentile, whereas the comparison group was placed in the 68th percentile. The participant scored above the 50th percentile in the TGMD-2 and showed lower fitness values than those in the comparison group. RECOMMENDATIONS FOR CLINICAL PRACTICE: Contrary to what is generally expected, supernumerary 47,XXX does not have to negatively impact motor competence, although a low health-related physical fitness can be present.

An analysis of the frequency of Y-chromosome microdeletions and the determination of a threshold sperm concentration for genetic testing in infertile men.

OBJECTIVE: To describe the prevalence of Y-chromosome microdeletions in a multi-ethnic urban population in London, UK. To also determine predictive factors and a clinical threshold for genetic testing in men with Y chromosome microdeletions. PATIENTS AND METHODS: A retrospective cohort study of 1473 men that were referred to a tertiary Andrology centre with male factor infertility between July 2004 and December 2016. All had a genetic evaluation, hormonal profile and 2 abnormal semen analyses. Those with abnormal examination findings also had targeted imaging performed. RESULTS: The prevalence of microdeletions was 4% (n = 58) in this study. These microdeletions were partitioned into the following regions: Azoospermia factors (AZF); AZFc (75%), AZFb+c (13.8%), AZFb (6.9%), AZFa (1.7%), and partial AZFa (1.7%). A high follicle-stimulating hormone level (P < 0.001) and a low sperm concentration (P < 0.05) were both found to be significant predictors for the identification of a microdeletion. Testosterone level, luteinising hormone level and testicular volume did not predict the presence of a microdeletion. None of the men with an AZF microdeletion had a sperm concentration of >0.5 million/mL. Lowering the sperm concentration threshold to this level retained the high sensitivity (100%) and increased the specificity (31%). This would produce significant cost savings when compared to the European Academy of Andrology/European Molecular Genetics Quality Network and European Association of Urology guidelines. The surgical sperm retrieval (SSR) rate after microdissection testicular sperm extraction was 33.2% in men with AZFc microdeletion. CONCLUSIONS: The prevalence of Y-chromosome microdeletions in infertile men appears to vary between populations and countries. A low sperm concentration was a predictive factor (P < 0.05) for identifying microdeletions in infertile males. A threshold for genetic testing of 0.5 million/mL would increase the specificity and lower the relative cost without adversely affecting the sensitivity. The rate of SSR was lower than that previously described in the literature.

A Spontaneous Pregnancy in a Patient with Turner Syndrome with 45,X/47,XXX Mosaicism: A Case Report and Review of the Literature.

BACKGROUND: Turner syndrome is a chromosomal abnormality, due to a total or partial loss of 1 of the X chromosomes and is mostly characterized clinically by short stature and primary ovarian insufficiency. Spontaneous pregnancies are rare (5%) and of relatively high risk. This is 1 of few reported cases of spontaneous conception and favorable prognosis in a patient with Turner syndrome and a 45,X/47,XXX karyotype. CASE: A 21-year-old woman with Turner mosaicism (45,X/47,XXX) who had a full-term, uncomplicated pregnancy after spontaneous conception, gave birth to a healthy female (46,XX) infant. SUMMARY AND CONCLUSION: Spontaneous pregnancies in women with Turner syndrome are a rarity. Fertility preservation methods are being discussed. Due to the high reported incidence of neonatal, obstetric, maternal, and especially cardiovascular complications in those pregnancies, close monitoring is essential.

Multicenter study of genetic abnormalities associated with severe oligospermia and non-obstructive azoospermia.

Objective * Chong Xie, Xiangfeng Chen, and Yulin Liu contributed equally to this work. Genetic defects are identified in nearly 20% of infertile males. Determining the frequency and types of major genetic abnormalities in severe male infertility helps inform appropriate genetic counseling before assisted reproductive techniques. Methods Cytogenetic results of 912 patients with non-obstructive azoospermia (NOA) and severe oligozoospermia (SOS) in Eastern China were reviewed in this multicenter study from January 2011 to December 2015. Controls were 215 normozoospermic men with offspring. Results Among all patients, 22.6% (206/912) had genetic abnormalities, including 27.3% (146/534) of NOA patients and 15.9% (60/378) of SOS patients. Chromosomal abnormalities (all autosomal) were detected in only 1.9% (4 /215) of controls. In NOA patients, sex chromosomal abnormalities were identified in 25.8% (138/534), of which 8% (43/534) had a 47,XXY karyotype or its mosaic; higher than the SOS group prevalence (1.1%; 4/378). The incidence of Y chromosome microdeletions was lower in the SOS group (13.2%; 50/378) than in the NOA group (17.8%; 95/534). Conclusions The high prevalence of genetic abnormalities in our study indicates the importance of routine genetic testing in severe male infertility diagnosis. This may help determine the choice of assisted reproductive technique and allow specific pre-implantation genetic testing to minimize the risk of transmitting genetic defects.

A finding in genetic polymorphism analysis study: A case of non-mosaic 47, XXX without manifestations.

Trisomy X (47, XXX) is a sex chromosome aneuploidy condition in which females have an extra X chromosome, compared to the 46, XX karyotype in typical females. There is considerable variation in the phenotype, with some individuals very mildly affected and others with more significant physical and psychological features. However, the trisomy X in this case, without any of these phenotype, is rarely reported. Here, we report a case found during DNA sample collection in a study of genetic polymorphism analysis of loci in Chinese ethnic group, of a female with neither laboratory or clinical signs of Triple X syndrome. She was born at her mother's 60years old and her father's 62years old. Advanced maternal age was found acting as a significant risk factor of Triplo-X. Moreover, her child are also born without manifestations of 47, XXX syndrome. Pedigree study demonstrated the normal karyotype of the children. A diagnosis of 47XXX was made on the basis of a chromosomal study. Therefore, laboratory investigations (including PCR amplification, more than two kinds of X-STR genotyping, G-banding karyotyping analysis and Pedigree study) are applied to rule out the possibility of Mosaicism (45, X0/47, XXX) and ascertain her 47XXX karyotype without mosaic. The objective of this study was to report a case of trisomy X, diagnostic investigation and management of the case, and to analysis the genetically possible reasons behind the case. To our knowledge, this case is a rare one, found in DNA sample collection for the estimation of gene frequency in the process of genetic polymorphism study, of non-mosaic 47, XXX without signs of physical syndrome and born healthy children. In this study, it revealed that the proportion of trisomy X would be more than official statistics and risk of systemic disabilities is lower than estimated. Moreover, we found out that sample mixture and mosaicism act as the interference factors in forensic test. Therefore, we draw the conclusion that attentions and certain improved methods should be applied to the diagnosis of non-mosaic triple X, which is of great significance in decreasing the interruptions in the whole process of forensic and paternity identification.

Enamel Pit Defects and Taurodontism in a Patient with Ring Chromosome 14 and 47,XXX.

The purpose of this paper is to describe the clinical findings and management of a case involving a patient with co-occurring ring chromosome 14 syndrome and 47,XXX presenting with enamel pit defects and taurodontism. Ring chromosome 14 syndrome is an unusual condition with uncontrolled seizure disorder as its most significant finding; 47,XXX (trisomy X; triple X) is a more common condition and has characteristic physical and behavioral findings. Neither condition has been associated with enamel pit defects.

Hypogonadotropic hypogonadism in a trisomy X carrier: phenotype description and genotype correlation.

We report on a 31-year old female who presented at genetic counseling for a small uterus, secondary amenorrhea and sterility. Gonadotropic hormone levels were low, suggesting a Hypogonadotropic Hypogonadism (HH) condition. Cytogenetic analysis demonstrated the presence of Trisomy X associated to an interstitial deletion of chromosome 4q13.2, resulting in the complete loss of a copy of the GNRHR gene. As GNRHR is known to be responsible for an autosomal recessive form of HH, we checked the status of the undeleted allele and we found the Q106R substitution. In conclusion, the results of our cytogenetic and molecular analyses have allowed us to clarify the etiology of the patient's condition.

Rapid and simultaneous screening of 47,XXY and AZF microdeletions by quadruplex real-time polymerase chain reaction.

We developed a quadruplex real-time PCR assay that allows rapid and simultaneous detection of 47,XXY and azoospermia factor (AZF) microdeletions on Y chromosome. The quadruplex assay consisted of four hydrolysis probes and primer sets. Three probes and the corresponding primers were used to qualitatively detect AZFa, AZFb, and AZFc deletions. For the detection of 47,XXY, the hydrolysis probe-mediated melting analysis was conducted to analyze the relative amounts of X and Y chromosomes. The quadruplex assay for detecting 47,XXY was characterized by very high analytical specificity (100%) in a wide template DNA range (2-100 ng). The detection limit of the assay was 2 ng of genomic DNA, and the optimal template DNA amount for the detection of 47,XXY was 25 ng. The quadruplex assay for detecting 47,XXY and AZF microdeletions has also demonstrated very high diagnostic sensitivity and specificity (100%). The assay was found to be rapid, sensitive, reliable, and inexpensive. This method is suggested to be applied as a first-step tool in genetic screening of patients with non-obstructive azoospermia and severe oligospermia.

The Turner syndrome in patient with 45X/47XXX mosaic karyotype--case report.

BACKGROUND: Turner syndrome (TS) is a gonadal dysgenesis related to partial or total lack of one of the X chromosomes. It this report we describe a young patient presenting some somatic features of TS, who underwent spontaneous puberty and was eumenoorheic up to the age of 23. METHODS: Using fluorescent in situ hybridization (FISH) mosaic karyotype (45X[131]/47XXX[9]) of TS and triple X syndrome was found. RESULTS: She presented uncommon for TS somatic hemihypotrophy and underwent growth hormone and surgical therapy. The patient was diagnosed with premature ovarian failure when she was 23, with absent follicular reserve. Clinical features of this case and a few published cases will be reviewed briefly.

Social cognition and underlying cognitive mechanisms in children with an extra X chromosome: a comparison with autism spectrum disorder.

Individuals with an extra X chromosome are at increased risk for autism symptoms. This study is the first to assess theory of mind and facial affect labeling in children with an extra X chromosome. Forty-six children with an extra X chromosome (29 boys with Klinefelter syndrome and 17 girls with Trisomy X), 56 children with autism spectrum disorder (ASD) and 88 non-clinical controls, aged 9-18 years, were included. Similar to children with ASD, children with an extra X chromosome showed significant impairments in social cognition. Regression analyses showed that different cognitive functions predicted social cognitive skills in the extra X and ASD groups. The social cognitive deficits were similar for boys and girls with an extra X chromosome, and not specific for a subgroup with high Autism Diagnostic Interview Revised autism scores. Thus, children with an extra X chromosome show social cognitive deficits, which may contribute to social dysfunction, not only in children showing a developmental pattern that is 'typical' for autism but also in those showing mild or late presenting autism symptoms. Our findings may also help explain variance in type of social deficit: children may show similar social difficulties, but these may arise as a consequence of different underlying information processing deficits.

Craniofacial and dental manifestations of triple X syndrome associated with congenital hypothyroidism: a case report.

Triple X syndrome (47,XXX) is a numerical chromosomal alteration that affects 1/1,000 women, in which the woman is born with an extra X chromosome. Some oral changes have been reported in the literature, as hypodontia, influence on deposition of crown enamel and discrepancies in cephalometric measurements. Other systemic complications may lead to oral abnormalities similar to those seen in triple X patients, such as congenital hypothyroidism (CH). This paper reports a triple X syndrome case associated with CH later treated. Besides delay in cognitive and intellectual development, the patient had changes in teeth development and in cephalometric measurements with deficiencies in the maxilla and mandible. This is the first report of a triple X syndrome associated with CH. Both conditions may result in changes in dentofacial development.

Rare case of massive congenital bilateral chylothorax in a hydropic fetus with true mosaicism 47,XXX/46,XX.

Fetal congenital chylothorax is a rare condition that occurs sporadically or can be associated with abnormal karyotype or structural chromosomal anomalies. We report a unique case of fetal congenital bilateral chylothorax associated with mosaicism 47,XXX/46,XX. A female fetus affected by massive bilateral hydrothorax and ascites was diagnosed at 34(+1) weeks of gestation. Previous ultrasonographic exams were completely normal. Immune causes of hydrops were excluded. Elective cesarean section was performed soon after bilateral thoracocentesis. The analysis of drained pleural fluid revealed its lymphatic nature. The fetal karyotyping, performed on chorionic villi at the 11th week, had shown mosaicism 47,XXX/46,XX, later confirmed in the newborn's blood. We hypothesized that chylothorax may be part of the phenotypic spectrum of 47 XXX karyotype and we suggest an ultrasound follow-up of the fetus at closer intervals than the routine timing for this condition, even if it is not usually characterized by severe phenotypic features.

First study of microdeletions in the Y chromosome of Algerian infertile men with idiopathic oligo- or azoospermia.

The human Y chromosome is essential for human sex determination and spermatogenesis. The long arm contains the azoospermia factor (AZF) region. Microdeletions in this region are responsible for male infertility. The objective of this study was to determine the frequency of Y microdeletions in Algerian infertile males with azoospermia and oligoasthenoteratozoospermia syndrome (OATS) and to compare the prevalence of these abnormalities with other countries and regions worldwide. A sample of 80 Algerian infertile males with a low sperm count (1-20 × 10(6) sperms/ml) as well as 20 fertile male controls was screened for Y chromosome microdeletions. 49 men were azoospermic and 31 men had OATS. Genomic DNA was isolated from blood and polymerase chain reaction was carried out with a set of 6 AZFa, AZFb and AZFc STS markers to detect the microdeletions as recommended by the European Academy of Andrology. Among the 80 infertile men screened for microdeletion, 1 subject was found to have microdeletions in the AZFc (sY254 and sY255) region. The deletion was found in azoospermic subjects (1/49, 2%). The overall AZF deletion frequency was low (1/80, 1.3%). AZF microdeletions were observed neither in the OATS group nor in the control group. The frequency of AZF microdeletions in infertile men from Algeria was comparable to those reported in the literature. We suggest analyzing 6 STS in the first step to detect Y microdeletions in our population.

Fold-change correction values for testicular somatic transcripts in gene expression studies of human spermatogenesis.

STUDY QUESTION: What are the reference values for delineating altered somatic cell gene expression from transcript enrichment/dilution in gene expression studies of human spermatogenesis? SUMMARY ANSWER: We have designed a crosstable and rule-of-thumb values for different stages of spermatogenic impairment that define the reference cut-off values for altered gene expression in Sertoli and Leydig cells in the context of impaired spermatogenesis. WHAT IS KNOWN ALREADY: Morphometrical studies have shown that on the cellular level, impaired spermatogenesis results in a relative enrichment of somatic cell types. However, until now it is not known how this affects transcript levels in gene expression studies. STUDY DESIGN, SIZE DURATION: In this study, 31 testis biopsies from men with different stages of spermatogenic impairment (full spermatogenesis, hypospermatogenesis, meiotic arrest, spermatogonial presence, Sertoli cell-only syndrome, complete tubular atrophy) were used to define reference ratios of somatic transcript enrichment/dilution. The reference ratios were validated on an independent test set of 28 samples and on gene expression data from men with Y-chromosomal microdeletions. PARTICIPANTS/MATERIAL, SETTING, METHODS: High-quality microarray data were filtered with respect to Sertoli- and Leydig-cell-specific genes. General reference enrichment/dilution factors for these two cell types for all combinations of spermatogenic impairment were calculated using robust permutation statistics. To validate the specificity of the filtered transcripts, we calculated ratios for an independent test set of spermatogenic impairment and for transcriptional data from men with Y-chromosomal microdeletions, and checked the functional enrichment (gene ontology) and cellular localization of the corresponding proteins in a histological database and assessed their correlation with testicular size. MAIN RESULTS AND THE ROLE OF CHANCE: Filtering of Sertoli- and Leydig-cell-specific genes resulted in a set of 54 and 332 transcripts, respectively. These were used in defining robust reference dilution/enrichment factors of somatic transcripts for all spermatogenic levels and were compiled in a reference crosstable. Validation on an independent test set showed ratios within 0.5 units of our reference crosstable. Analysis of the resulting transcripts with respect to functional enrichment for Sertoli- and Leydig-cell-specific functions and protein expression, as obtained from an immunohistochemical database, indicated filtering of data sets highly enriched for Sertoli and Leydig cell function. The dilution/enrichment ratios differed significantly when transcripts were interrogated in samples with Y-chromosomal microdeletions, pointing to an overall decreased expression of somatic markers in a genetically altered background. LIMITATIONS, REASONS FOR CAUTION: The defined reference ratios might apply with some restrictions in samples that display very heterogeneous histology (e.g. Sertoli cell only with a significant proportion of spermatogenic foci) or when spermatogenic impairment is a consequence of an altered genetic background. WIDER IMPLICATIONS OF THE FINDINGS: The reference dilution/enrichment values for somatic testicular transcripts as defined in this study are to be seen as cut-off values for discriminating between simple transcript dilution/enrichment as a consequence of an altered germ cell composition and actual transcriptional regulation. Future studies dealing with transcriptional changes in testicular somatic cells in a background of altered germ cell quantities should consider these correction factors in order to avoid the description of transcriptional changes that are based simply on shifts in somatic cellular quantities. STUDY FUNDING/COMPETING INTEREST(S): Financial support was from grant Sp721/1-3 of the German Research Foundation. There are no competing interests to be declared.