Prenatal Ultrasound Diagnosis of Congenital Diaphragmatic Hernia in a Fetus With Fryns "Anophthalmia-Plus" Syndrome: A Case Report.

Fryns syndrome is an extremely rare autosomal recessive disorder and is characterized by congenital diaphragmatic hernia (CDH), dysmorphic facial features, distal limb hypoplasia, pulmonary hypoplasia, and characteristic-associated anomalies that lead to a high mortality rate. We present a prenatally diagnosed new case of Fryns "anophthalmia-plus" syndrome (FAPS) in a 41-year-old pregnant woman. An ultrasonographic examination at 22 weeks of gestation demonstrated left CDH with mediastinal shift, hypoplastic thorax with presumptive pulmonary hypoplasia, craniofacial anomalies, left anophthalmia, and distal limb hypoplasia. A genetic analysis of the fetal karyotype was held, which was negative for any known chromosomal or single gene abnormalities. After genetic counseling about the risks associated with these ultrasonographic findings, the parents opted for pregnancy termination. Timely identification or suspicion of Fryns syndrome during the early stages of pregnancy could facilitate parental guidance and enable the development of suitable strategies for prenatal treatment and/or perinatal care.

The Association of MMP-2, MMP-9, and MMP-13 Gene Polymorphisms With Knee Osteoarthritis in the Greek Population.

Introduction Primary knee osteoarthritis (OA) is a multifactorial degenerative joint disorder characterized by articular cartilage degradation. Matrix metalloproteinases (MMPs) have been reported to play a vital role in OA pathogenesis, significantly contributing to extracellular matrix (ECM) catabolism. The purpose of this study is to investigate the association of MMP-2 -1575G/A (rs243866), MMP-9 836A/G (rs17576), and MMP-13 -77A/G (rs2252070) gene polymorphisms with knee OA in the Greek population. Methods One hundred patients (24% males, mean age: 68.3 years) with primary knee OA were included in the study along with 100 controls (47% males, mean age: 65.2 years). Genotypes were identified through polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) technique. Allelic and genotypic frequencies were compared between patients and controls. Results The MMP-13 -77A/G polymorphism was significantly associated with knee OA in the crude analysis (P = 0.008). After binary logistic regression analysis, the dominant model of the MMP-13-77A/G (AG + GG versus AA) was found to be associated with increased risk for knee OA (odds ratio (OR) = 2.290, 95% confidence interval (95%CI) = 1.059-4.949, P= 0.035). Compared to the A allele, the G allele in the MMP-13rs2252070 locus was a predictive factor for knee OA (OR = 2.351, 95%CI = 1.134-4.874, P= 0.022). No significant associations were detected for the MMP-2 -1575G/A and MMP-9 836A/G polymorphisms (P > 0.05). Conclusions The present study shows that the MMP-2 -1575G/A and MMP-9 836A/G polymorphisms are not significantly associated with primary knee OA in the Greek population. The MMP-13 -77A/G was found to be a significant risk factor for knee OA in the Greek population. Additional research is needed to verify this association in larger and different populations, in different joints, to elucidate the role of this single nucleotide polymorphism (SNP) in OA pathogenesis.

Cracking the Code: Investigating the Correlation between Aerobic Vaginitis and Preterm Labor.

Aerobic vaginitis (AV) is a distinct clinical entity characterized by inflammation and abnormal vaginal microflora. Often mistaken for bacterial vaginosis, AV remains relatively unknown and underdiagnosed. AV's understanding is evolving, with some experts suggesting it may primarily be an immunological disorder, the prevalence of which has a range of 7-13% in non-pregnant women and 4.1-8.3% during pregnancy. Pregnancy can affect susceptibility to vaginal infections, leading to adverse outcomes for the woman and the newborn. This review summarizes the correlation between AV and adverse pregnancy outcomes, particularly preterm birth, the leading cause of morbidity and mortality among neonates. An improved understanding of AV's impact on pregnancy outcomes can lead to early recognition, proper management, and effective interventions. While some studies support an association between AV and preterm labor, the existing knowledge of this relationship remains limited. The evidence suggests that AV may contribute to adverse pregnancy outcomes, mainly preterm birth, but further research is needed to establish a definitive link. Further studies are needed to investigate the underlying mechanisms and clarify AV's role in premature labor. A comprehensive understanding of AV's impact on pregnancy outcomes is crucial for early recognition, appropriate management, and effective interventions.

Breaking Bad News During Prenatal Screening: The Role of Professional Obstetricians and Midwives in Greece.

INTRODUCTION: Breaking bad news is one of the most difficult responsibilities in medical practice. Although medical staff in clinical practice often encounter situations that necessitate the announcement of unpleasant news, there is a lack of training regarding their communication with patients and their families. Effective interaction between medical staff and pregnant women constitutes a crucial component of breaking down unpleasant news. This research aimed to investigate the knowledge and attitude of health professionals, particularly obstetricians, and midwives, regarding the announcement of bad news during prenatal screening. METHODS: The study was conducted between September 2017 and April 2018. One hundred professional obstetricians and midwives involved in fetal and prenatal medicine in Greece were part of the study. The study consisted of two parts: the first covered the emotional state of healthcare professionals during the announcement of unpleasant news, and the second covered the appropriate way to inform unpleasant results during prenatal testing. RESULTS: In this study, only 41% of the participants considered that they felt comfortable discussing issues related to the diagnosis of an unpleasant result during prenatal testing with the pregnant woman/patient, or her relatives, and 85% accepted that they had experienced feelings of sadness, anxiety, or guilt when announcing unpleasant results. Furthermore, 87% of the participants believed that the non-verbal communication component (eye contact, body language) plays an important role in breaking bad news. Finally, 65% considered that prolonged monitoring of the ultrasound screen during prenatal screening does not increase the anxiety of pregnant women when carried out for a better medical opinion. CONCLUSIONS: Delivering bad news during prenatal screening creates stress for the parents. As far as the ethical, cultural, psychological, and legal complicity of healthcare professionals is concerned, communicating unpleasant news has been a subject of discussion by many experts. It is important to understand the concerns of women regarding the risks of counseling.

p16/Ki-67 Dual Staining Is a Reliable Biomarker for Risk Stratification for Patients With Borderline/Mild Cytology in Cervical Cancer Screening.

BACKGROUND/AIM: To evaluate p16/Ki-67 dual-staining performance for detection of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) in the management of women with minor cervical abnormalities. PATIENTS AND METHODS: All 759 enrolled patients were tested for cytology, high-risk human papillomavirus (HR-HPV) and dual p16/Ki-67 staining. RESULTS: Positivity rates for HR-HPV and dual staining increased as dysplasia was worsened from non-CIN (37.6% and 0%) to CIN1 (62.5% and 1.6%) and CIN2+ (98.7% and 97.3%), respectively. HPV18 and HPV16 exhibited the highest odds ratios (53.16 and 11.31) in the CIN2+ group. Both p16/Ki-67 dual staining and HR-HPV presented similar sensitivities (97.3% and 98.7%, respectively) for CIN2+ detection. Dual staining specificity, however, was 99.3%, significantly higher compared to HR-HPV testing (52.2%). The utility of dual staining was evaluated in different screening strategies and appeared to reduce the number of colposcopies required for the detection of CIN2+ cases. CONCLUSION: p16/Ki-67 dual-staining cytology is a surrogate triage biomarker in cytology-based screening programs, with high performance for efficient risk stratification of women with mild cervical abnormalities.

The p16/ki-67 assay is a safe, effective and rapid approach to triage women with mild cervical lesions.

OBJECTIVE: The aim of this study was to evaluate the diagnostic accuracy and efficiency of p16/ki-67 dual stain in the identification of CIN2+ lesions, in Greek women with ASCUS or LSIL cytology. METHODS: A total of 200 women, 20 to 60 years old, were enrolled in the study. All samples were cytologically evaluated and performed for p16/ki-67 and high-risk HPV (HR-HPV) test. All patients were referred to colposcopy for biopsy and histological evaluation. Three cervical cancer (CC) screening strategies were designed and the total direct medical costs of the procedures during our clinical trial were evaluated, from a healthcare perspective. RESULTS: HPV 16 as expected was the most common HR-HPV type followed by HPV 31 and HPV 51. The risk for CIN2+ was significantly higher in HPV 16/18 positive cases. p16/ki-67 demonstrated a high sensitivity for CIN2+ identification in both ASCUS and LSIL groups (90.4% and 95%, respectively). HR-HPV test with sensitivity 52.3% and 65.5%, as well as colposcopy with sensitivity 14.3% and 36% respectively in ASCUS and LSIL group, showed inferior results compared to p16/ki-67. The specificity of p16/ki-67 for ASCUS and LSIL was 97.2% and 95.2% respectively, inferior only to colposcopy: 100% and 100%, lacking however statistical significance. HR-HPV test instead, presented the lowest specificity: 76.4% and 71.4% respectively in comparison to the other two methods. From a healthcare perspective, the costs and benefits of the tests implementation for the annual screening and triaging, in three CC screening strategies, were also calculated and discussed. CONCLUSIONS: The results of the study indicate that p16/ki-67 is a safe and rapid assay that could be used to detect CIN2+ among women with mild cervical lesions, presenting both high sensitivity and specificity and could minimize the psychological and economic burden of HPV screening.

Mythological figures in art and genetics: Current perspectives on cyclopia and chimerism.

Mythical figures have been part of human cultural tradition for centuries, worldwide. Some of them were totally imaginary, others were likely inspired by individuals with malformation syndromes, while others are composites of parts of different species. Various artists have created works of art based on these mythical or hybrid beings, such as cyclops and chimeras. The plethora of representations of artworks in ancient, but also contemporary art (statues, paintings, illustrations, photographs, installations) is proof that they still continue to be a source of inspiration, although their rendering and interpretation have changed over time. Contemporary medical genetic knowledge has revealed the underlying pathogenesis and causative molecular basis of malformation syndromes and delineates the corresponding phenotypes. Today, many figures once viewed as mythical are reflected in living humans with medical diagnoses. Ancient terms that arose in mythology-cyclopia, chimera/ism, and others-live on in the medical literature.

Placental Mesenchymal Dysplasia: Ultrasound Characteristics and Diagnostic Pitfalls.

Placental mesenchymal dysplasia (PMD) is a rare, benign developmental anomaly with a reported prevalence of 0.02% (Arizawa and Nakayama, 2002). It is characterized by placentomegaly with multiple cystic lesions of the stem villi and vascular anomalies (Pawoo and Heller, 2014). Early detection of PMD has been described during routine prenatal ultrasound (Vaisbuch et al., 2009). The sonographic characteristics of PMD include increased placental thickness and multiple cystic areas within the placenta with either an absence of blood flow or with low venous Doppler signals (Vaisbuch et al., 2009). The differential diagnosis of multicystic placental lesions with the presence of a live fetus include partial molar pregnancy, multiple hematomas, chorioangioma Beckwith-Wiedemann syndrome and PMD. Chorioangiomas are well circumscribed masses within the placenta and they are characterized by the presence of a single feeding vessel with the same pulse rate as the umbilical cord (Zalel et al., 2002). Invasive prenatal testing is required for the exclusion of partial molar pregnancy and Beckwith-Wiedemann Syndrome (Vaisbuch et al., 2009). Definitive diagnosis of PMD is based on the pathologic examination of the placenta. Histology reveals aneurysm or dilated blood vessels that may be thrombosed. The stem villi are edematous and enlarged with thick-walled vessels, without trophoblastic proliferation (Pawoo and Heller, 2014). This case report highlights the significance of the early detection of PMD, illustrates the pitfalls in differential diagnosis and provides valuable insights regarding PMD management in a clinical setting.

Contribution of RAD51D germline mutations in breast and ovarian cancer in Greece.

RAD51D gene's protein product is known to be involved in the DNA repair mechanism by homologous recombination. RAD51D germline mutations have been recently associated with ovarian and breast cancer (OC and BC, respectively) predisposition. Our aim was to evaluate the frequency of hereditary RAD51D mutations in Greek patients. To address this, we have screened for RAD51D germline mutations 609 BRCA1- and BRCA2-negative patients diagnosed with OC, unselected for age or family history, and 569 BC patients diagnosed under 55 years and with an additional relative with BC or OC. We identified four pathogenic mutations in four unrelated individuals with family history of BC and/or OC. Three of the RAD51D carriers had developed BC, while the other one was an OC patient, thus accounting for a mutation frequency of 0.16% in the OC cohort and 0.53% in the BC cohort. One of the detected mutations is novel (c.738 + 1G > A), whereas the rest had been detected previously (p.Gln151Ter, p.Arg186Ter, and p.Arg300Ter). It is noteworthy that the 4 carrier families had 13 BC cases and only 4 OC cases. Our data support that RAD51D should be implemented into the comprehensive multigene panel, as mutation carriers may benefit from the administration of PARP inhibitors.

Efficacy and safety of pulsatile gonadotropin-releasing hormone therapy among patients with idiopathic and functional hypothalamic amenorrhea: a systematic review of the literature and a meta-analysis.

OBJECTIVE: To systematically review and appraise the existing evidence in relation to the efficacy and safety of pulsatile gonadotropin-releasing hormone (pGnRH) for the treatment of women with hypothalamic amenorrhea (HA). DESIGN: Systematic review and meta-analysis. SETTING: Not applicable. PATIENT(S): A total of 35 studies (three randomized and 32 observational) encompassing 1,002 women with HA. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Primary outcomes: ovulation rate (OvR), pregnancy per ovulatory cycle rate (POR), and live birth per ovulatory cycle rate (LBOR). SECONDARY OUTCOMES: multiple gestation (MG), ovarian hyperstimulation syndrome (OHSS), and superficial thrombophlebitis (ST) rates. The summary measures were expressed as proportions and 95% confidence intervals (CI). RESULT(S): Pulsatile GnRH treatment appears to achieve high OvRs. A trend toward high PORs and LBORs among women with HA is demonstrated. SC pGnRH achieves comparable OvR compared with IV pGnRH. The incidence of OHSS is low and of mild severity. Treatment with pGnRH is associated with low but slightly higher MG rates compared with the general population. IV administered pGnRH is rarely associated with ST. CONCLUSION(S): The high OvRs leading to a high rate of singleton pregnancies and the low likelihood of OHSS render the pGnRH treatment modality both effective and safe for the treatment of women with HA of either primary or secondary origin.

Premature Ovarian Insufficiency: An Adolescent Series.

STUDY OBJECTIVE: To study the presentation and causes of premature ovarian insufficiency (POI) in adolescents. DESIGN: Retrospective notes review. SETTING: Tertiary referral outpatient clinic for pediatric and adolescent gynecology. PARTICIPANTS: Adolescents with POI. INTERVENTIONS: Standard POI evaluation. MAIN OUTCOME MEASURES: Age and clinical symptoms at presentation, causative factors for POI, if identified. RESULTS: We identified 22 girls with POI, with a mean age of 15.6 years. Eight of them presented with delayed puberty, 3 with primary amenorrhea, and the remainder presented with either irregular bleeding (n = 9) or secondary amenorrhea (n = 2). For those who presented with delayed puberty, only 3 were found to have a sex chromosome abnormality. A clear cause for the POI was identified in 3 further cases. CONCLUSION: Although POI in adolescents traditionally is associated with primary amenorrhea and delayed puberty, a proportion of girls will present with irregular bleeding that might be mistaken for expected menstrual disturbances of puberty, thus delaying the diagnosis. We identified a clear cause for POI in 6 cases. Although there were no familial cases of POI, it remains a possibility that genetic reasons might be involved in the pathogenesis.

Association of MMP-1 -1607 1G/2G (rs1799750) polymorphism with primary knee osteoarthritis in the Greek population.

Osteoarthritis is the most common form of arthritis with still unknown pathogenic etiology and considerable contribution of genetic factors. One of the mechanisms of cartilage degradation in osteoarthritis is enzymatic proteolysis of the extracellular matrix by metalloproteinases. MMP-1, produced by chondrocytes and synovial cells, is a major proteinase of the MMPs family. The present study aims at evaluating the association of MMP1 gene -1607 1G/2G (rs1799750) polymorphism with primary knee osteoarthritis in the Greek population. One hundred fifty five patients with primary symptomatic knee osteoarthritis participated in the study along with 139 controls. Genotypes were determined using PCR-RLFP technique. Allelic and genotypic frequencies were compared between both study groups. There was no significant association between MMP1 -1607 1G/2G polymorphism and knee osteoarthritis, in crude analysis; however, after multiple logistic regression analysis, 1G/2G was associated with reduced odds of knee osteoarthritis by 75% in males, compared to genotypes 1G/1G + 2G/2G, adjusting for age and BMI (adjusted OR: 0.25, 95% CI: 0.069, 0.910, p = 0.035). The present study shows that MMP1 -1607 1G/2G (rs1799750) polymorphism might be a risk factor for knee osteoarthritis susceptibility in the Greek population. Further investigations are needed to confirm this association in the pathogenesis of osteoarthritis.

Association of NADPH oxidase p22phox gene C242T, A640G and -930A/G polymorphisms with primary knee osteoarthritis in the Greek population.

Osteoarthritis (OA) is the most common form of arthritis with still unknown pathogenic etiology and considerable contribution of genetic factors. Recently, a new emerging role of oxidative stress in the pathology of OA has been reported, lacking however elucidation of the underlying mechanism. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase being a complex enzyme produced by chondrocytes, presents the major source of reactive oxygen species and main contributor of increased oxidative stress. The present study aims to evaluate the association of NADPH oxidase p22phox gene C242T, A640G and -A930G polymorphisms with primary knee OA in the Greek population. One hundred fifty five patients with primary symptomatic knee OA participated in the study along with 139 matched controls. Genotypes were determined using polymerase chain reaction and restriction fragment length polymorphism technique. Allelic and genotypic frequencies were compared between both study groups. NADPH p22phox -A930G polymorphism was significantly associated with knee OA in the crude analysis (P = 0.018). No significant difference was detected for C242T and A640G polymorphisms (P > 0.05). The association between -A930G polymorphism and knee OA disappeared when the results were adjusted for obesity (P = 0.078, odds ratio 0.54, 95 % CI 0.272-1.071). The interaction between all three polymorphisms was not significant. The present study shows that NADPH oxidase p22phox gene C242T, A640G and -A930G polymorphisms are not risk factors for knee OA susceptibility in the Greek population. Further studies are needed to give a global view of the importance of this polymorphism in the pathogenesis of OA.

Mutation screening in the Greek population and evaluation of NLGN3 and NLGN4X genes causal factors for autism.

Molecular and neurobiological evidence for the involvement of neuroligins (particularly NLGN3 and NLGN4X genes) in autistic disorder is accumulating. However, previous mutation screening studies on these two genes have yielded controversial results. The present study explores, for the first time, the contribution of NLGN3 and NLGN4X genetic variants in Greek patients with autistic disorder. We analyzed the full exonic sequence of NLGN3 and NLGN4X genes in 40 patients strictly fulfilling the Diagnostic and Statistical Manual of Mental Disorders, 4th ed. criteria for autistic disorder. We identified nine nucleotide changes in NLGN4X--one probable causative mutation (p.K378R) previously reported by our research group, one novel variant (c.-206G>C), one nonvalidated single nucleotide polymorphism (SNP, rs111953947), and six known human SNPs reported in the SNP database--and one known human SNP in NLGN3 also reported in the SNP database. The variants identified are expected to be benign. However, they should be investigated in the context of variants in interacting cellular pathways to assess their contribution to the etiology of autism.

De novo interstitial duplication of the 15q11.2-q14 PWS/AS region of maternal origin: Clinical description, array CGH analysis, and review of the literature.

The 15q11-q13 PWS/AS critical region involves genes that are characterized by genomic imprinting. Multiple repeat elements within the region mediate rearrangements, including interstitial duplications, interstitial triplications, and supernumerary isodicentric marker chromosomes, as well as the deletions that cause Prader-Willi syndrome (PWS) and Angelman syndrome (AS). Recently, duplications of maternal origin concerning the same critical region have been implicated in autism spectrum disorders (ASD). We present a 6-month-old girl carrying a de novo duplication of maternal origin of the 15q11.2-q14 PWS/AS region (17.73 Mb in size) [46,XX,dup(15)(q11.2-q14)] detected with a high-resolution microarray-based comparative genomic hybridization (array-CGH). The patient is characterized by severe hypotonia, obesity, microstomia, long eyelashes, hirsutism, microretrognathia, short nose, severe psychomotor retardation, and multiple episodes of drug-resistant epileptic seizures, while her brain magnetic resonance imaging (MRI) documented partial corpus callosum dysplasia. In our patient the duplicated region is quite large extending beyond the Prader-Willi-Angelman critical region (PWACR), containing a number of genes that have been shown to be involved in ASD, exhibiting a severe phenotype, beyond the typical PWS/AS clinical manifestations. Reporting of similar well-characterized clinical cases with clearly delineated breakpoints of the duplicated region will clarify the contribution of specific genes to the phenotype.

A substitution involving the NLGN4 gene associated with autistic behavior in the Greek population.

Autism is a neurodevelopmental disorder characterized by clinical, etiologic, and genetic heterogeneity. During the last decade, predisposing genes and genetic loci were under investigation. Recently, mutations in two X-linked neuroligin genes, neuroligin 3 (NLGN3) and neuroligin 4 (NLGN4), have been implicated in the pathogenesis of autism. In our ongoing survey, we screened 169 patients with autism for mutations linked with autism. In the preliminary study of specific exons of NLGN3 and NLGN4 genes, we identified the p.K378R substitution (c.1597 A > G) in exon 5 of the NLGN4 gene in a patient who was found to have mild autism and normal IQ at 3 years of age. The same mutation has previously been found in a patient with autism. It is important that, for the first time, a specific mutation in neuroligins is confirmed in a molecular screen in another homogeneous ethnic population. This finding further contributes to consideration of neuroligins as probable candidate genes for future molecular genetic studies, suggesting that a defect of synaptogenesis may predispose to autism.

Strong linkage disequilibrium for the frequent GJB2 35delG mutation in the Greek population.

Approximately one in 1,000 children is affected by severe or profound hearing loss at birth or during early childhood (prelingual deafness). Up to 40% of congenital, autosomal recessive, severe to profound hearing impairment cases result from mutations in a single gene, GJB2, that encodes the connexin 26 protein. One specific mutation in this gene, 35delG, accounts for the majority of GJB2 mutations detected in Caucasian populations. Some previous studies have assumed that the high frequency of the 35delG mutation reflects the presence of a mutational hot spot, while other studies support the theory of a common founder. Greece is among the countries with the highest carrier frequency of the 35delG mutation (3.5%), and a recent study raised the hypothesis of the origin of this mutation in ancient Greece. We genotyped 60 Greek deafness patients homozygous for the 35delG mutation for six single nucleotide polymorphisms (SNPs) and two microsatellite markers inside or flanking the GJB2 gene. The allele distribution in the patients was compared to 60 Greek normal hearing controls. A strong linkage disequilibrium was found between the 35delG mutation and markers inside or flanking the GJB2 gene. Furthermore, we found a common haplotype with a previous study, suggesting a common founder for the 35delG mutation.

Genetic polymorphisms in the UGT1A1 gene and breast cancer risk in Greek women.

Uridine diphospho-glucuronosyltransferase 1 (UGT1A1) is involved in estradiol glucuronidation, which may play a central role in the etiology of breast cancer. A common insertion/deletion polymorphism in the TATAA-box of the promoter region of UGT1A1 results in decreased initiation of transcription, and has been associated with breast cancer risk in different ethnic groups. In the present study, the role of the above genetic variation at the UGT1A1 locus in breast cancer susceptibility was investigated in a homogeneous population. Our case-control study included 136 women with breast cancer and 186 healthy female controls of Greek origin. The polymorphism A(TA)nTAA in the promoter region of UGT1A1 gene was studied using the Fragment Analysis Software of an automated DNA sequencer and three genotypes (homozygous 7/7, heterozygous 6/7, and normal homozygous 6/6) were identified. No significant associations were observed between the 7/7 genotype and breast cancer risk, indicating that further studies in Caucasian women are needed to elucidate the role of UGT1A1 polymorphism in breast cancer risk.

Monogenic nonsyndromic otosclerosis: audiological and linkage analysis in a large Greek pedigree.

OBJECTIVE: The aim of our study was to characterize the hearing impairment in a large multigenerational Greek family with autosomal dominant nonsyndromic otosclerosis and to perform genetic linkage analysis to known otosclerosis loci and collagen genes. In addition, we looked for mutations in the NOG gene to rule out congenital stapes ankylosis syndrome. METHODS: Audiological analysis of the affected persons was based on multiple linear regression (MLR) analysis and construction of age-related typical audiograms (ARTA). Genotyping of microsatellite DNA polymorphisms for known otosclerosis (OTSC) loci or collagen genes and linkage analysis using the MLINK computer program were performed. The coding region of the NOG gene was screened for mutations by direct DNA sequencing. RESULTS: The hearing loss in this family appears in childhood as conductive, but soon becomes mixed. Because the additional sensorineural component is progressive, this finally has lead to a pure sensorineural hearing loss in some family members, as the conductive component is masked. Audiological analysis showed an age-independent conductive component and a progressive frequency-specific sensorineural component. Linkage analysis excluded linkage to the four known otosclerosis loci (OTSC1, OTSC2, OTSC3, and OTSC5), as well as to the COL1A1 and COL1A2 genes. Mutation analysis of the coding region of the NOG gene did not reveal any disease causing mutation. CONCLUSIONS: This study represents the first description of a detailed audiological analysis in a large pedigree segregating otosclerosis as a monogenic autosomal dominant trait. Exclusion of the four known otosclerosis loci in this family shows that monogenic otosclerosis is a genetically heterogeneous disease involving at least five different genes. A mutation in the NOG gene is not the underlying molecular mechanism of the early onset otosclerosis segregating in this family.

Prevalence of GJB2 mutations in prelingual deafness in the Greek population.

OBJECTIVE: Mutations in the gene encoding the gap junction protein connexin 26 (GJB2) have been shown as a major contributor to prelingual, sensorineural, nonsyndromic, recessive deafness. One specific mutation, 35delG, has accounted for the majority of the mutations detected in the GJB2 gene in Caucasian populations. The aim of our study was to determine the prevalence and spectrum of GJB2 mutations in prelingual deafness in the Greek population. METHODS: In a collaboration with the major referral centers for childhood deafness in Greece, patients were examined by an extensive questionnaire to exclude syndromic forms and environmental causes of deafness and by allele-specific polymerase chain reaction (PCR) for the detection of the 35delG mutation. Patients heterozygous for the 35delG mutation were further analyzed by direct genomic sequencing of the coding region of the GJB2 gene. RESULTS: The 35delG mutation was found in 42.2% of the chromosomes in 45 familial cases of prelingual, nonsyndromic deafness (18 homozygotes and 2 heterozygotes) and in 30.6% of the chromosomes in 165 sporadic cases (45 homozygotes and 11 heterozygotes). Direct genomic sequencing in heterozygous patients revealed the L90P (2 alleles), W24X (2 alleles), R184P (2 alleles), and 291insA (1 allele) mutations. CONCLUSION: Mutations in the GJB2 gene are responsible for about one third of prelingual, sensorineural, nonsyndromic deafness in the Greek population, and allele-specific PCR is an easy screening method for the common 35delG mutation.