ABSTRACT
Introduction: utism spectrum disorder (ASD) is a heterogeneous clinical condition, and its genetic basis is widely confirmed. The chromosomal microarray analysis (CMA) is a first-line diagnostic test that identifies copy number variants (CNVs). Some of these genomic rearrangements are associated with ASD, but the meaning of most of them is still unknown. Materials and methods: We performed a comparative genome hybridization (array-CGH) analysis in 130 children with confirmed ASD. Genetic results were analyzed and compared to clinical phenotype. Results and discussion.: 61/130 children carry CNVs, 44 presenting variants of unknown significance (u-CNVs), and 17 with susceptibility-CNVs (c-CNVs). Clinical evaluation showed no differences in cognitive abilities, language and EEG abnormalities, ASD symptoms among CNVs group and other patients. Finally, we highlight the role of GPHN, IMMP2L and ZMYND11, as ASD susceptibility genes. Conclusions: Our findings underscore the importance of array-CGH in ASD children since new CNVs and emerging genes appear to be associated with different clinical pictures.
Subject(s)
Autism Spectrum Disorder , Humans , Child , Autism Spectrum Disorder/genetics , Comparative Genomic Hybridization , Cognition , Language , DNA-Binding Proteins , Cell Cycle Proteins , Co-Repressor ProteinsABSTRACT
Background: Alopecia areata (AA) spares the stem cell compartment and attacks only the base of the hair follicle, which is surrounded by infiltrating lymphocytes. AA is associated with polymorphisms in immune-related genes and with decreased function of CD4+CD25+ T regulatory (Treg) cells. Treg function is modulated by the costimulatory molecules, like inducible costimulator (ICOS) that are crucial in orienting T cell differentiation and function so that they strongly impact on the immunologic decision between tolerance or autoimmunity development. Objective: The aim of our study was to investigate the possible association of AA with single-nucleotide polymorphisms (SNP) present in the ICOS 3'-untranslated region (3'UTR) region and to elucidate how SNPs modulate ICOS gene expression by affecting miRNA binding sites. Methods: This is a case-control study performed in 184 patients with AA and 200 controls. ICOS gene and miRNA expression were analyzed by real-time polymerase chain reaction. Results: The genotype carrying the rs4404254(C) [p = 0.012, OR (95% CI): 0.5 (0.3-0.8)] and rs4675379(C) [p = 0.015, OR (95% CI): 0.3 (0.1-0.8)] 3' UTR alleles was more frequently observed in AA patients than in controls and correlated with a reduced ICOS expression. miR-1276 significantly suppressed ICOS expression by binding to the 3'UTR of ICOS mRNA. Also, we observed that, miR-101 and miR-27b are upregulated, while miR-103 and miR-2355-3p are downregulated in peripheral blood mononuclear cells of AA patients compared to controls. Conclusion: Our data show that rs4404254 and rs4675379 SNPs of ICOS gene are associated with AA and also reveal that the presence of rs4404254 polymorphism correlates with ICOS post-transcriptional repression by microRNA binding.
ABSTRACT
OBJECTIVE: We provide a review of the literature about the Androgen Insensitivity Syndrome (AIS), its onset and associated developmental anomalies and the genetic alterations causing it. MATERIALS AND METHODS: We searched PubMed with a larger emphasis on the physiology, genetics and current management of AIS. RESULTS: AIS is an X-linked recessive Disorder of Sex Development (DSD). It is caused by mutations of the Androgen Receptor, and their large amount and heterogeneity (missense and nonsense mutations, splicing variants, deletions, and insertions) are responsible for the wide spectrum of possible phenotypes of patients, divided into Partial AIS (PAIS) and Complete AIS (CAIS). Once the clinical and laboratory investigations have laid the foundation for a diagnostic hypothesis, it is important to identify the actual karyotype of the individual and search for the mutation in the Androgen Receptor to diagnose with certainty the syndrome. Alternatively, in the absence of such evidence, the diagnosis should more properly be an AIS-like condition, which we describe as well in our report. CONCLUSIONS: The management of this DSD is based on pharmacotherapies, surgery and psychological support: all of them must be directed to facilitate the patient's life, considering his/her sexual identity.
Subject(s)
Androgen-Insensitivity Syndrome/genetics , Mutation , Receptors, Androgen/genetics , Androgen-Insensitivity Syndrome/diagnosis , Androgen-Insensitivity Syndrome/therapy , Humans , MaleABSTRACT
PURPOSE: Real-time virtual sonography (RVS) is a new technique that synchronizes real-time ultrasonography (US) and multiplanar reconstructed magnetic resonance imaging (MRI). The purpose of this study was to evaluate the feasibility and ability of RVS to assess the main pathologies in fetuses with suspected US anomalies. METHOD AND MATERIALS: Real-time virtual sonography (Hitachi, HI VISION Ascendus) was offered to 30 patients who had undergone fetal MRI. The acquired MRI image dataset was loaded into the fusion system and displayed together with the real-time US image. The ability of RVS to assess the main anatomical sites and fetal anomalies was evaluated. RESULTS: Real-time virtual sonography was technically possible in all cases. From a total of 30 patients, RVS helped the diagnosis in 10 cases. In 15 cases of encephalic pathology, fusion imaging improved the accuracy of the diagnosis; in the other 5 cases, MRI was superior to US even when using the RVS. CONCLUSION: This is a study on the feasibility and practical use of RVS. Thanks to information from both US and MRI, RVS allowed better identification of the fetal pathologies and improved the performance of the ultrasound examination. In our experience, it was really helpful in pathologies that would benefit from US follow-up.
Subject(s)
Magnetic Resonance Imaging , Nervous System Malformations/diagnostic imaging , Neuroimaging/methods , Ultrasonography, Prenatal/methods , Feasibility Studies , Female , Humans , Pregnancy , Prospective StudiesABSTRACT
Alopecia areata (AA), an autoimmune disease affecting anagen stage hair follicles, is associated with polymorphisms in immune-related genes and with decreased number of CD4+ CD25+ T regulatory cells (Treg). Treg function is modulated by the forkhead box protein 3 (FOXP3) transcription factor and by inducible costimulator (ICOS), through interaction with the relative ligand, ICOSLG, whose genes are polymorphic. The aim of the study was to investigate whether specific single nucleotide polymorphisms (SNPs) of the rs2294020 FOXP3 and/or rs378299 ICOSLG genes may be associated with AA. A case-control study was performed in 120 AA patients and 84 controls. SNPs were analyzed by gene sequencing. FOXP3 and ICOSLG gene expressions were analyzed by real-time PCR. Increased frequencies of the genotype carrying the FOXP3 rs2294020-3675(A) [P = 0.002, OR (95 % CI): 2.55 (1.2-2.7)] or the ICOSLG rs378299-509(C) [P = 0.01, OR (95 % CI): 2.21 (1.1-2.6)] allelic variants were observed in AA patients than in controls. The genotype carrying the combination of the FOXP3 rs2294020-3675(A) and ICOSLG rs378299-509(C) allelic variants with the HLA DQB1*03 allele was more frequently present in AA patients than in controls (P = 0.04). The presence of the FOXP3 rs2294020-3675(A) or the ICOSLG rs378299-509(C) allelic variant was associated with reduced relative gene expression in AA patients. These data suggest that rs2294020 SNP of FOXP3 gene and rs378299 SNP of ICOSLG gene are associated with AA and with a reduced expression of the FOXP3 and ICOSLG genes in alopecia patients.
Subject(s)
Alopecia Areata/genetics , Forkhead Transcription Factors/genetics , Genetic Predisposition to Disease , Inducible T-Cell Co-Stimulator Ligand/genetics , Polymorphism, Single Nucleotide , Promoter Regions, Genetic , Adolescent , Adult , Aged , Case-Control Studies , Child , Female , Gene Expression Profiling , Gene Frequency , Genetic Association Studies , Genotype , Genotyping Techniques , Humans , Male , Middle Aged , Real-Time Polymerase Chain Reaction , Sequence Analysis, DNA , Young AdultABSTRACT
The variable number of tandem repeat polymorphism in the 3'-untranslated region of the dopamine transporter gene (DAT) may influence the variability of the therapeutic response to methylphenidate (MPH) in Attention Deficit/Hyperactivity Disorder (ADHD). For this reason we evaluated the neuropsychological functioning after a prolonged period of MPH treatment and after a specific time from MPH suspension. Relationship between DAT VNTR genotypes and neurocognitive response to MPH was analyzed in a sample of 108 drug-naive ADHD patients. The performance of children with ADHD on measures of working memory, inhibition and planning was assessed at 4, 8 and 24 weeks and at 8 weeks after MPH withdrawal. Patients with 9/9 genotype evidenced an improvement in response inhibition and working memory only at 4 weeks of treatment, in planning at 24 weeks of therapy and after 8 weeks of MPH suspension. Patients with 9/10 showed an improvement in response inhibition at 4, 8 and 24 weeks of treatment, in planning at 24 weeks and after 8 weeks of MPH suspension. Patients with 10/10 evidenced an improvement in response inhibition and working memory at 4, 8 and 24 weeks of treatment and in planning at 4, 8 and 24 weeks of treatment and after 8 weeks of suspension. These results indicate that the 9/9 ADHD genotype has a different response at 24 weeks treatment with MPH. 10/10 DAT allele seems to be associated with an increased expression level of the dopamine transporter and seems to mediate the MPH treatment response in ADHD patients.
Subject(s)
Attention Deficit Disorder with Hyperactivity/genetics , Central Nervous System Stimulants/therapeutic use , Cognition Disorders/drug therapy , Dopamine Plasma Membrane Transport Proteins/genetics , Methylphenidate/therapeutic use , Pharmacogenetics , Adolescent , Attention Deficit Disorder with Hyperactivity/complications , Child , Cognition Disorders/etiology , Cognition Disorders/genetics , Female , Genotype , Humans , Inhibition, Psychological , Longitudinal Studies , Male , Memory, Short-Term/drug effects , Minisatellite Repeats/genetics , Neuropsychological Tests , Problem Solving/drug effects , Psychiatric Status Rating Scales , Time FactorsABSTRACT
BACKGROUND: Alopecia areata (AA) is a multifactorial disease characterized by hair loss especially from the scalp. As for other autoimmune conditions, the major histocompatibility complex (HLA) region is associated with AA susceptibility. OBJECTIVE: To provide evidence for the association of specific HLA-DQB1 and HLA-DRB1 alleles with AA in an Italian population, using a case-control approach. METHODS: We performed a case-control study to investigate whether HLA-DQB1 and -DRB1 alleles predispose to AA in the Italian population. HLA class II typing was performed in 85 patients with AA and 210 healthy controls from the same ethnic group. RESULTS: An increased frequency of DQB1*03, coding for DQ7 heterodimers, and a decreased rate of the DQB1*06 allele were observed in patients when compared with controls; the greatest and significant difference was in the group of cases with a more severe phenotype [AA>50% patients (more than 50% hair loss) vs. controls, P=4·5×10(-3) , P(c)=0·031, odds ratio (OR) 2·01, 95% confidence interval (CI) 1·22-3·31 and P=2·5×10(-3) , P(c)=0·017, OR 0·22, 95% CI 0·07-0·72, respectively]. DQB1*03, serologically related to DQ8 or coding for DQ9 molecules, was not associated with AA susceptibility. Out of all patients, 65·9% carried DQ7 heterodimers compared with 49·5% of the controls (P=7·3×10(-3) , OR 1·97, 95% CI 1·17-3·32) and DQ7 prevalence rose to 76·3% in patients with AA>50% (P=1·7×10(-3) , OR 3·28, 95% CI 1·48-7·27). No significant difference was found in the distribution of DRB1 variants or phenotypes among cases and controls. CONCLUSION: Our data show a correlation between the HLA-DQB1 locus and the occurrence of AA in Italy supporting DQB1*03(DQ7) as a predisposing allele for the disease and the relevance of the HLA genetic test in the clinical management of AA.
Subject(s)
Alopecia Areata/genetics , HLA-DQ beta-Chains/genetics , HLA-DRB1 Chains/genetics , Polymorphism, Genetic/genetics , Adult , Alopecia Areata/ethnology , Case-Control Studies , Female , Gene Frequency , Humans , Italy/ethnology , Male , Middle Aged , Phenotype , Young AdultABSTRACT
Keratosis pilaris (KP) is a follicular hyperkeratosis disorder which is frequently detected in the adult population (44%), mostly in female adolescents (80%). It is a genetic autodominant dermatosis with variable penetrance, but no specific gene association has been determined, even though association to the presence of chromosome 18p deletion has been reported in some cases. We report the case of a 51-year-old Caucasian woman affected by keratosis pilaris gradually progressing with age and with a story of multiple abortions. Standard karyotype and CGH array analyses did not reveal any genetic abnormality. Virological analyses detected the presence of HPV 36 DNA inside the dorsum biopsy, leading to hypothesize its involvement in the evolution of the lesion. Clinical history and patient examination led the diagnosis of an idiopathic case of Ulerythema ophryogenes. The analysis of more cases could be useful to verify the involvement of cutaneous HPV in the progression of the clinical manifestation of the KP variants.
Subject(s)
Diagnostic Errors/prevention & control , Skin/pathology , Abnormalities, Multiple/diagnosis , Abnormalities, Multiple/genetics , Abnormalities, Multiple/pathology , Abnormalities, Multiple/virology , Abortion, Spontaneous/genetics , Base Sequence , Biopsy , Comparative Genomic Hybridization , DNA, Viral/analysis , Darier Disease , Eyebrows/abnormalities , Eyebrows/pathology , Eyebrows/virology , Female , Humans , Karyotyping , Keratosis/diagnosis , Keratosis/genetics , Keratosis/pathology , Keratosis/virology , Middle Aged , Molecular Sequence Data , Papillomaviridae/genetics , Predictive Value of Tests , Skin/virology , Stillbirth/geneticsABSTRACT
Scrotal elephantiasis is very rare disease in industrialized countries, where it is mainly due to surgery, irradiation or malignancies. It can be defined as idiopathic only when the possible congenital, infectious and compressive causes are excluded. We report a case of massive scrotal lymphoedema in an adult Caucasian patient, in Italy. He presented an extremely voluminous scrotal mass measuring 50 x 47 x 13 cm (weight 18 kg), which extended below his knees, invalidating all his daily activities. The patient was hospitalized in order to undergo to surgical treatment. Although genetic causes were searched and the possible role of infectious agents and compressive factors was evaluated, no etiology was ascertained. Histopathologic examination showed non-specific chronic inflammation, confirming the diagnosis of idiopathic elephantiasis. One year after surgical treatment, the patient is healthy without recurrence signs.
Subject(s)
Elephantiasis/surgery , Scrotum/pathology , Adult , Elephantiasis/diagnosis , Elephantiasis/pathology , Humans , Male , Vascular Endothelial Growth Factor Receptor-3/geneticsABSTRACT
Allgrove syndrome (or triple A syndrome) is a rare autosomal recessive disorder characterized by alacrima, achalasia, ACTH-resistant adrenal insufficiency and autonomic/neurological abnormalities. It is caused by mutations in the AAAS gene, located on chromosome 12q13. We describe a 42-year-old patient who presented with neuropathy and was found to have alacrima, achalasia, mild autonomic dysfunction with significant central and peripheral nervous system involvement. She was later diagnosed with oligosymptomatic triple A syndrome. Sequencing of the AAAS gene identified two heterozygous mutations within exon 14 and its donor splice site (p.L430F-c.1288C>T and c.1331+1G>T), one of which is novel. Allgrove syndrome should be suspected in patients with neurological impairment associated with two or more of the main symptoms (alacrima, achalasia or adrenal insufficiency).
Subject(s)
Adrenal Insufficiency/genetics , Esophageal Achalasia/genetics , Genetic Predisposition to Disease/genetics , Mutation/genetics , Nerve Tissue Proteins/genetics , Nuclear Pore Complex Proteins/genetics , Adrenal Insufficiency/ethnology , Adrenal Insufficiency/metabolism , Adult , Autonomic Nervous System Diseases/genetics , Autonomic Nervous System Diseases/metabolism , Autonomic Nervous System Diseases/physiopathology , DNA Mutational Analysis , Esophageal Achalasia/ethnology , Esophageal Achalasia/metabolism , Exons/genetics , Female , Genotype , Heterozygote , Humans , Italy , Peripheral Nervous System Diseases/genetics , Peripheral Nervous System Diseases/metabolism , Peripheral Nervous System Diseases/physiopathology , RNA Splice Sites/genetics , SyndromeABSTRACT
Allgrove syndrome is a rare autosomal recessive disorder characterised by childhood onset, alacrima, oesophageal achalasia, adrenocortical insufficiency, neurological and occasionally autonomic involvement. Although the disease has been associated with mutations in the ALADIN gene on chromosome 12q13, it is genetically heterogeneous. The case we report is interesting because of its onset in adulthood, long duration of disease and prominent neurological dysfunctions. After the onset of neurological abnormalities the diagnosis went unrecognised for years until the patient presented for evaluation of dysphagia. The presence of achalasia with dysphagia, adrenal insufficiency, reduced tear production, optic atrophy and peripheral motor-sensory neuropathy with axonal loss led us to clinically diagnose Allgrove syndrome even though a genetic study showed no mutations in the ALADIN gene exons. The case we report shares many clinical features with Allgrove syndrome and, even with the limitations of a single case, underlines the variability in this syndrome and the need for appropriate investigations along with a multidisciplinary approach.
Subject(s)
Adrenal Insufficiency/genetics , Chromosome Disorders/genetics , Chromosomes, Human, Pair 12 , Esophageal Achalasia/genetics , Nerve Tissue Proteins/genetics , Nuclear Pore Complex Proteins/genetics , Adrenal Insufficiency/complications , Adult , Chromosome Disorders/complications , Dry Eye Syndromes/etiology , Esophageal Achalasia/complications , Genes, Recessive , Humans , Male , MutationSubject(s)
GATA4 Transcription Factor/genetics , Heart Septal Defects, Atrial/genetics , Homeodomain Proteins/genetics , Mutation , Transcription Factors/genetics , Adolescent , Adult , Child , Child, Preschool , Female , Genotype , Heart Septal Defects, Atrial/diagnosis , Homeobox Protein Nkx-2.5 , Humans , Male , Pedigree , PhenotypeABSTRACT
Partial epilepsy with auditory features occasionally segregates in families as an autosomal dominant trait. In some families mutations in the leucine-rich glioma inactivated (LGI1) gene have been identified. Sporadic cases might harbour either denovo or low-penetrant LGI1 mutations, which will substantially alter the family risk for epilepsy. We selected sixteen sporadic patients with cryptogenic temporal lobe epilepsy and partial seizures with auditory features. We compared clinical features of these patients with those of published autosomal dominant family cases. We screened these patients for LGI1 mutations. Comparing the sporadic patients with the published familial cases no difference in either the primary auditory features or in the other associated epileptic manifestations was identified. Sequence analysis of the whole LGI1 gene coding regions in sporadic patients did not reveal changes in the LGI1 gene. The genetic analysis demonstrates that LGI1 is not a major gene for sporadic cases of partial epilepsy with auditory features at least in the Italian population. Screening of sporadic patients for LGI1 mutations appears not useful in genetic counselling of these patients.
Subject(s)
Epilepsy, Partial, Sensory/genetics , Epilepsy, Temporal Lobe/genetics , Genetic Predisposition to Disease/genetics , Mutation/genetics , Proteins/genetics , Adult , DNA Mutational Analysis , Epilepsy, Partial, Sensory/diagnosis , Epilepsy, Partial, Sensory/physiopathology , Epilepsy, Temporal Lobe/diagnosis , Epilepsy, Temporal Lobe/physiopathology , Female , Genetic Testing , Humans , Intracellular Signaling Peptides and Proteins , Italy , Male , Middle AgedSubject(s)
LEOPARD Syndrome/diagnosis , LEOPARD Syndrome/genetics , Mutation , Protein Tyrosine Phosphatases/genetics , Adolescent , Adult , Amino Acid Sequence , Base Sequence , Child , Child, Preschool , DNA Mutational Analysis , Female , Humans , Infant , Intracellular Signaling Peptides and Proteins , Male , Middle Aged , Molecular Sequence Data , Protein Tyrosine Phosphatase, Non-Receptor Type 11Subject(s)
Dystonia/genetics , Gene Deletion , Hearing Loss, Sensorineural/genetics , Membrane Transport Proteins/genetics , Protein-Tyrosine Kinases/genetics , Adult , Agammaglobulinaemia Tyrosine Kinase , Agammaglobulinemia/complications , Agammaglobulinemia/genetics , Agraphia/complications , Agraphia/drug therapy , Agraphia/genetics , Botulinum Toxins/therapeutic use , Dystonia/complications , Dystonia/drug therapy , Genetic Diseases, X-Linked , Hearing Loss, Sensorineural/complications , Humans , Immunoglobulins, Intravenous/therapeutic use , Male , Membrane Transport Proteins/deficiency , Mental Disorders/complications , Mental Disorders/genetics , Mitochondrial Precursor Protein Import Complex Proteins , Polymerase Chain Reaction , Protein-Tyrosine Kinases/deficiency , Syndrome , Vision Disorders/complications , Vision Disorders/geneticsABSTRACT
In testicular descent to the scrotum, a multistep process, many anatomical and hormonal factors play a role. Cryptorchidism occurs in about 1-2% of males and may cause secondary degeneration of the testes. Animal models have shown that abnormalities, in the calcitonin gene-related peptide (CgRP) activity, could be relevant in the pathogenesis of cryptorchidism. We performed a mutation screening by PCR exon amplification, single-strand conformation polymorphism (SSCP) and sequencing in four candidate genes, CgRPs (alphaCgRP, betaCgRP), their receptor (CgRPR) and the receptor component protein (CgRP-RCP), in 90 selected cases of idiopathic unilateral or bilateral cryptorchidism. Mutation screening of the coding regions and intron-exon boundaries revealed some polymorphic variants but no pathogenic sequence changes. These preliminary data suggest that these genes are not major factors for cryptorchidism in humans.
Subject(s)
Calcitonin Gene-Related Peptide/genetics , Cryptorchidism/genetics , Mutation/physiology , Adult , Exons/genetics , Gene Frequency , Genetic Testing , Humans , Immunohistochemistry , Introns/genetics , Male , RNA Probes , Reverse Transcriptase Polymerase Chain ReactionSubject(s)
Abnormalities, Multiple/genetics , Heart Defects, Congenital/pathology , Noonan Syndrome/genetics , Protein Tyrosine Phosphatases/genetics , Abnormalities, Multiple/pathology , Adolescent , Adult , Child , Child, Preschool , DNA/chemistry , DNA/genetics , DNA Mutational Analysis , Developmental Disabilities/pathology , Family Health , Female , Genotype , Growth Disorders/pathology , Humans , Infant , Intracellular Signaling Peptides and Proteins , Lentigo/pathology , Male , Mutation , Noonan Syndrome/pathology , Pedigree , Phenotype , Polymorphism, Single-Stranded Conformational , Protein Tyrosine Phosphatase, Non-Receptor Type 11 , SyndromeABSTRACT
The authors describe an Italian kindred with nine individuals affected by hyperkalaemic periodic paralysis associated with paramyotonia congenita (hyperPP/PMC). Periodic paralysis was particularly severe, with several episodes a day lasting for hours. The onset of episodes was unusually early, beginning in the first year of life and persisting into adult life. The paralytic episodes were refractory to treatment. Patients described minimal paramyotonia, mainly of the eyelids and hands. All affected family members carried the threonine to methionine substitution at codon 704 (T704M) in exon 13 of the skeletal muscle voltage gated sodium channel gene (SCN4A). The association between T704M and the hyperPP/PMC phenotype has been only recently revealed. Nevertheless, such a severe phenotype has never been reported so far in families with either hyperPP or hyperPP/PMC. These data further broaden the clinical spectrum of T704M and support the evidence that this mutation is a common cause of hyperPP/PMC.
Subject(s)
Myotonic Disorders/genetics , Paralysis, Hyperkalemic Periodic/genetics , Sodium Channels/genetics , Adolescent , Adult , Age of Onset , Aged , Aged, 80 and over , Codon/genetics , Female , Humans , Male , Middle Aged , Myotonic Disorders/complications , Myotonic Disorders/pathology , NAV1.4 Voltage-Gated Sodium Channel , Paralysis, Hyperkalemic Periodic/complications , Paralysis, Hyperkalemic Periodic/pathology , Pedigree , Phenotype , Point Mutation , Severity of Illness IndexABSTRACT
Hearing impairment (HI) is the most frequent sensory defect with wide genetic heterogeneity. Approximately 80% of genetic hearing loss is non-syndromic and 15-25% of exhibit autosomal dominant inheritance. We analysed an Italian three generation family in which non-syndromic hearing impairment is transmitted as an autosomal dominant trait. Onset of HI in all affected subjects occurred in the second decade of life, with subsequent gradual progression from moderate to profound loss. HI was bilateral and symmetrical, involving all frequencies. After exclusion of the known DFNA loci with markers from the Hereditary Hearing Loss Homepage (URL: http://dnalab-www.uia.ac.be/dnalab/hhh), a genome wide scan was carried out using 358 highly informative microsatellite markers. Significant linkage (Zmax=4.21, theta=0) was obtained with chromosome 2p12 markers. The results were confirmed by multipoint analysis (Zmax=4.51), using the location score method. Haplotype analysis defined a 9.6 cM disease gene interval on chromosome 2 without overlap with the other identified loci. Fine mapping and identification of candidate genes are in progress.