RESUMO
De novo cytogenetically balanced reciprocal non-Robertsonian translocations are rare findings in clinical cytogenetics and might be associated with an abnormal phenotype. Knowledge of the parental origin and mechanisms of formation is still limited. By microdissection of the derivative chromosomes and their normal homologs from metaphases followed by microsatellite-mediated marker analysis we identified 7 cases of paternal and 3 cases of maternal origin in a cohort of 10 patients with de novo cytogenetically balanced reciprocal non-Robertsonian translocations. Neither in the maternal nor in the paternal group of our study parental age seems to be increased. Together with the data from the literature our results confirm that the majority of de novo cytogenetically balanced reciprocal translocations are of paternal origin, but the preponderance does not appear to be as distinct as previously thought and the paternal age does not seem to be necessarily a major contributing factor.
Assuntos
Translocação Genética , Anormalidades Múltiplas/genética , Adulto , Cromossomos Humanos/genética , Estudos de Coortes , Citogenética , Pai , Feminino , Humanos , Recém-Nascido , Deficiência Intelectual/genética , Cariotipagem , Masculino , Repetições de Microssatélites , MãesRESUMO
UNLABELLED: We report on the fatal clinical course of a 3 year old male Turkish patient suffering from osteopetrosis caused by a homozygous mutation in the chloride channel gene ClCN7 with developing pancytopenia and severe neurological impairment. Hepatosplenomegaly due to extramedullary hematopoesis, severe transfusion-dependent anemia and growth failure initially suggested metabolic or oncologic disorder. Particular haematological parameters like tear drop cells basophilic punctation of the polymorphonuclear cells in the absence of haemolysis caused the diagnostic X-ray investigations of the skull and vertebral column. Raised serum creatinkinase-BB isoenzyme and genetic testing were in line with the diagnose of osteopetrosis at an age of 2(1/2) years. CONCLUSION: Osteopetrosis is a rare but considerable differential diagnose for unclarified change in haematopoetic cell lines combined with severe neurological symptoms mimicking metabolic or haematological disease. Because of this rare disease a consensus protocol for diagnostics, treatment and follow up of patients suffering from osteopetrosis is recently worked out from the European Group of Blood and Marrow Transplantation (EBMT) and the European Society for Immundeficiencies (ESID) to build up a central registry for this disease (available by ansgar.schulz@uniklinik-ulm.de).
Assuntos
Canais de Cloreto/genética , Análise Mutacional de DNA , Hematopoese Extramedular/genética , Homozigoto , Doenças Neurodegenerativas/genética , Osteopetrose/genética , Fosfatase Alcalina/sangue , Pré-Escolar , Aberrações Cromossômicas , Códon/genética , Creatina Quinase Forma BB/sangue , Diagnóstico Diferencial , Epilepsia/diagnóstico por imagem , Epilepsia/genética , Éxons/genética , Evolução Fatal , Genes Recessivos/genética , Humanos , Masculino , Doenças Neurodegenerativas/diagnóstico por imagem , Osteopetrose/diagnóstico por imagem , Radiografia , Crânio/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagemRESUMO
Joubert syndrome (JS) is a clinically and genetically heterogeneous ciliopathy characterized by episodic hyperpnea and apnea, hypotonia, ataxia, cognitive impairment and ocular motor apraxia. The "molar tooth sign" is pathognomonic of this condition. Mutations in the MKS1 gene are a major cause of Meckel-Gruber syndrome (MKS), the most common form of syndromic neural tube defects, frequently resulting in perinatal lethality. We present the phenotype and genotype of a child with severe JS and agenesis of the corpus callosum (ACC). In our patient, a next generation sequencing (NGS) approach revealed the following two variants of the MKS1 gene: first, a novel missense variant [ c.240G > T (p.Trp80Cys)], which affects a residue that is evolutionarily highly conserved in mammals and ciliates; second, a 29 bp deletion in intron 15 [c.1408-35_1408-7del29], a founder mutation, which in a homozygous state constitutes the major cause of MKS in Finland. We review the MKS1-variants in all of the eleven JS patients reported to date and compare these patients to our case. To our knowledge, this is the first patient with Joubert syndrome and agenesis of the corpus callosum where a potentially causal genotype is provided.
Assuntos
Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/genética , Agenesia do Corpo Caloso/genética , Cerebelo/anormalidades , Anormalidades do Olho/diagnóstico , Anormalidades do Olho/genética , Doenças Renais Císticas/diagnóstico , Doenças Renais Císticas/genética , Mutação , Fenótipo , Proteínas/genética , Retina/anormalidades , Alelos , Sequência de Aminoácidos , Substituição de Aminoácidos , Encéfalo/patologia , Ordem dos Genes , Loci Gênicos , Genótipo , Humanos , Lactente , Masculino , Análise de Sequência de DNARESUMO
OBJECTIVE: Keratitis-ichthyosis-deafness (KID) syndrome is a rare congenital ectodermal dysplasia characterized by the association of hyperkeratotic skin lesions, moderate to profound sensorineural hearing loss and vascularizing keratitis. Mutations in the GJB2 gene coding for connexin 26, a component of gap junctions in epithelial cells, have been observed in several KID patients. Variable ocular manifestations of the disease in 3 patients with molecular genetically confirmed KID syndrome are reported. DESIGN: Retrospective case series. METHODS: Clinical examination and molecular genetic analysis for mutations in the GJB2 gene were performed in 3 patients with KID syndrome ages 5, 13, and 41 years. RESULTS: Visual acuity ranged from normal to severe visual loss. The ocular signs included loss of eyebrows and lashes, thickened and keratinized lids, trichiasis, recurrent corneal epithelial defects, superficial and deep corneal stromal vascularization with scarring, keratoconjunctivitis sicca, and, in one patient, presumed limbal insufficiency. Whereas ocular surface integrity could be maintained with artificial tears in one patient, and an epithelial defect healed under conservative treatment in the second patient, multiple surgical procedures including superficial keratectomies, limbal allograft transplantation with systemic immunosuppression, amniotic membrane transplantation, lateral tarsorrhaphies, and lamellar keratoplasty could not preserve useful vision in the third patient. CONCLUSIONS: KID syndrome may affect the ocular adnexae and surface with variable severity independent of the age of the patient. Lid abnormalities, corneal surface instability, limbal stem cell deficiency with resulting corneal complications, and dry eye are the main ocular manifestations.
Assuntos
Surdez/diagnóstico , Oftalmopatias/diagnóstico , Doenças do Cabelo/diagnóstico , Eritrodermia Ictiosiforme Congênita/diagnóstico , Ceratite/diagnóstico , Adolescente , Adulto , Pré-Escolar , Conexina 26 , Conexinas/genética , Neovascularização da Córnea/diagnóstico , Substância Própria/irrigação sanguínea , Surdez/congênito , Surdez/tratamento farmacológico , Oftalmopatias/tratamento farmacológico , Oftalmopatias/genética , Pestanas/patologia , Doenças Palpebrais/diagnóstico , Feminino , Humanos , Eritrodermia Ictiosiforme Congênita/tratamento farmacológico , Ceratite/congênito , Ceratite/tratamento farmacológico , Ceratoconjuntivite Seca/diagnóstico , Masculino , Mutação , Soluções Oftálmicas/uso terapêutico , Estudos Retrospectivos , Síndrome , Acuidade VisualRESUMO
We report on a moderately mentally retarded 12-year-old boy of short stature showing the most complex chromosomal rearrangement (CCR) within a single chromosome ever described. A de novo derivative chromosome 21 was recognized in GTG-banding shortly after birth. However, the nature of the rearrangement remained obscure up to the application of the chromosome 21-specific centromere-near multicolor-FISH (subcenM-FISH) probe set and of six selected locus-specific probes along chromosome 21. An unbalanced 9-break-event was uncovered with breakpoints in 21p13, 21p13-->12, 21q11.2, 21q21.1, 21q22.11, 21q22.11, 21q22.12, 21q22.22 and 21q22.3. A deletion of 21q22.11 was detected by application of the BAC probe bk249H10. The karyotype can be described as 46,XY,der(21)(:p13-->p1213::q22.3-->q22.22:: q11.2-->p1213::q11.2-->q21.1::q22.11-->q21.1::q22.12--> q22.22::p13-->p13). The clinical signs can either be due to gene inactivation in connection with structural changes at the break and fusion regions, to the building of new fusion genes within the CCR and/or to the deletion of genes in 21q22.11.
Assuntos
Quebra Cromossômica , Deleção Cromossômica , Cromossomos Humanos Par 21 , Transtornos do Crescimento/genética , Deficiência Intelectual/genética , Anormalidades Múltiplas/patologia , Criança , Bandeamento Cromossômico , Transtornos do Crescimento/diagnóstico , Humanos , Hibridização in Situ Fluorescente , Deficiência Intelectual/diagnóstico , Cariotipagem , MasculinoRESUMO
Two genes responsible for a nonspecific form of X-linked mental retardation (MRX28 and MRX33) were localized by linkage analysis with 40 highly polymorphic DNA markers situated along the entire the X chromosome. In family 1, the gene could be mapped within a 14-cM interval at Xq28, distal to the recombining marker DXS1113 (MRX28). The maximum LOD score was 2.75, with DXS52 at phi = .0. In family 2, the gene was localized within a 30-cM interval at Xp11.4-22.12 between the recombining markers DXS365 and MAOB, including the DMD gene (MRX33). Maximum LOD scores of 2.82 were obtained with markers DMD-STR49, DMD-DysII, CYBB, and DXS1068.
Assuntos
Mapeamento Cromossômico , Ligação Genética , Deficiência Intelectual/genética , Cromossomo X , Pré-Escolar , DNA , Feminino , Triagem de Portadores Genéticos , Humanos , Lactente , Escore Lod , Masculino , LinhagemRESUMO
An Austrian family with nonsyndromic X-linked mental retardation (MRX) is reported in which the obligatory carrier females are normal, and 5 affected males have mild to moderate mental retardation. Linkage analysis indicated an X pericentromeric localization, with flanking markers DXS989 and DXS1111 and a maximum multipoint LOD score of 2.09 (straight theta = 0) for the 7 cosegregating markers DXS1243, CybB, MAOB, DXS988, ALAS2, DXS991, and AR. MRX58 thus mapped within a 50-cM interval between Xp11.3 and Xq13.1 and overlapped with 23 other MRX families already described. This pericentromeric clustering of MRX families suggests allelism, with a minimum of 2 X-linked mental retardation (XLMR) genes in this region.
Assuntos
Deficiência Intelectual/genética , Cromossomo X/genética , Centrômero/genética , Mapeamento Cromossômico , Citogenética , Saúde da Família , Feminino , Ligação Genética , Humanos , Escore Lod , Masculino , Repetições de Microssatélites , LinhagemRESUMO
We describe clinical, pathological and radiological findings in 15 cases of sporadic and familial lower spine agenesis with additional anomalies of the axial skeleton and internal organs and speculate about the cause and pathogenesis of this malformation complex. We show that all of these findings are defects of blastogenesis, originate in the primary developmental field and/or the progenitor fields, thus representing polytopic field defects. This concept appears applicable in our cases and makes such terms such as "caudal regression syndrome" or "axial mesodermal dysplasia spectrum" redundant.
Assuntos
Anormalidades Múltiplas , Vértebras Lombares/anormalidades , Anormalidades Múltiplas/diagnóstico por imagem , Anormalidades Múltiplas/embriologia , Anormalidades Múltiplas/mortalidade , Adulto , Consanguinidade , Evolução Fatal , Feminino , Feto/anormalidades , Feto/diagnóstico por imagem , Idade Gestacional , Humanos , Lactente , Recém-Nascido , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/embriologia , Masculino , Radiografia , SíndromeRESUMO
Cranial computed tomography in the initial stage of the intermediate phenotype of maple syrup urine disease (MSUD) demonstrates diffuse, symmetric hypodensities in white and grey matter, which show a complete return to normal after early introduction of an adequate protein-restrictive diet. If diagnosis of this disease is missed or delayed, progressive global (end-stage) atrophy will take place over several years. A decrease in density values correlates well with the total cerebral lipid and water content (closely related to myelinisation), whereas progression and grade of atrophy show a relationship with the severity of pathological white and grey matter changes that are not demonstrable with computed tomography but can be proven histologically. Analysis of both morphological parameters corresponds well with clinical-neurological outcome and therapeutic success.
Assuntos
Encéfalo/diagnóstico por imagem , Doença da Urina de Xarope de Bordo/genética , Tomografia Computadorizada por Raios X , Proteínas Alimentares/administração & dosagem , Feminino , Humanos , Lactente , Doença da Urina de Xarope de Bordo/diagnóstico por imagem , Doença da Urina de Xarope de Bordo/dietoterapia , Monitorização Fisiológica/métodosRESUMO
Craniopharyngioma is the third most common intracranial tumor in childhood. Following surgery, virtually all patients present with hypopituitarism and are at considerable risk of tumor recurrence. Secondary tumors, however, are rare, occurring usually 10 years after diagnosis and associated with poor prognosis. We report on a 5 year-old boy in whom craniopharyngioma was diagnosed due to unilateral visual loss. After surgery he underwent conventional radiation therapy with a total tumor dose of 55 Gy, and had hormonal support with DDAVP, thyroxine, and a variable dose of hydrocortisone. Growth velocity declined slowly in the first 4 years, but improved later on again without GH therapy despite abnormal provocative tests. At the age of 15 years he developed peripheral facial nerve palsy due to a malignant astrocytoma (WHO grade III/IV). Repeated conventional radiation therapy with an additional stereotactic boost and chemotherapy could not prevent the fatal outcome. This observation may temper the use of radiosurgery in benign intracranial tumors.
Assuntos
Astrocitoma/diagnóstico , Neoplasias do Tronco Encefálico/diagnóstico , Craniofaringioma/radioterapia , Craniofaringioma/cirurgia , Segunda Neoplasia Primária/diagnóstico , Neoplasias Hipofisárias/radioterapia , Neoplasias Hipofisárias/cirurgia , Astrocitoma/sangue , Astrocitoma/patologia , Astrocitoma/radioterapia , Neoplasias do Tronco Encefálico/sangue , Neoplasias do Tronco Encefálico/patologia , Neoplasias do Tronco Encefálico/radioterapia , Pré-Escolar , Terapia Combinada , Evolução Fatal , Hormônios/sangue , Humanos , Imageamento por Ressonância Magnética , Masculino , Invasividade Neoplásica , Fatores de TempoRESUMO
Cytogenetic analysis, fluorescent in situ hybridization (FISH) and polymerase chain reaction (PCR) were applied to characterize the Y-chromosomal breakpoints of three XX male patients. Two of these patients show a breakpoint within a protein kinase gene, PRKY, previously described as a hotspot of ectopic recombination between homologous regions on X and Y chromosomes during male meiosis. The slightly different clinical phenotypes of the three patients cannot be correlated with the localization of the breakpoints.
Assuntos
Síndrome de Turner/genética , Cromossomo Y/genética , Adulto , Criança , Gonadotropina Coriônica , Citogenética , DNA/genética , Hormônios Esteroides Gonadais/sangue , Humanos , Hibridização in Situ Fluorescente , Lactente , Cariotipagem , Masculino , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Cromossomo Y/ultraestruturaRESUMO
A case of Schinzel-Giedion syndrome, a rare malformation syndrome with a life expectancy of less than 2 years is described. Features present in this and previous cases are discussed. The association of agenesis of the corpus callosum with the Arnold-Chiari malformation found in this patient has not previously been described.
Assuntos
Anormalidades Múltiplas , Hidronefrose/diagnóstico por imagem , Ureter/anormalidades , Feminino , Humanos , Recém-Nascido , Síndrome , Ultrassonografia Pré-NatalRESUMO
Monosomy 1p36 is a recently delineated contiguous gene syndrome, which is now considered to be one of the most common subtelomeric microdeletion syndromes. We report four unrelated patients with subtle deletions within 1p36 confirmed by high resolution karyotyping and FISH. All exhibited severe psychomotor retardation. Microcephaly, seizures, and visual impairment occurred in three subjects. Results of a first routine karyotyping were unrevealing in three probands. The diagnosis was primarily suggested on the basis of a distinct pattern of facial anomalies in all except the first case. This report illustrates that monosomy 1p36 may be recognized clinically, at least in some patients, whereas the diagnosis is easily missed on routine karyotype.
Assuntos
Cromossomos Humanos Par 1 , Anormalidades Craniofaciais/genética , Deficiência Intelectual/genética , Monossomia/patologia , Criança , Pré-Escolar , Feminino , Humanos , Hibridização in Situ Fluorescente , Lactente , Deficiência Intelectual/patologia , Masculino , FenótipoRESUMO
Menkes' disease is a rare X-linked multisystemic lethal disorder of copper transport metabolism. Failure of synthesis of several copper enzymes explains most of the clinical features, which were characterised by neurodegenerative symptoms and connective tissue manifestations. Most cases are still prone to rapidly progressive cerebral degeneration and early death in the first few years. Since CNS-dysfunction usually preceeds development of the pathognomonic "steely" hair, delay of clinical diagnosis and onset of therapeutic intervention precludes longlasting neurological benefit. This is particularly true for patients with large deletions or severe truncations of the responsible ATP7A gene. We report on our own experience with a patient, who was diagnosed to be affected by Menkes' syndrome at the age of one year, due to the specific hair texture and biochemical abnormalities. Molecular investigation revealed a total deletion of exon 15 of the ATP7A gene. Heterozygosity was confirmed by means of real-time PCR in the child's mother, but could be excluded in the grandmother and other female relatives at risk. Therapeutic support with subcutaneous injection of copper-histidinate normalised diminished copper and coeruloplasmin serum levels, but was unable to influence the clinical course and to prevent the fatal outcome at the age of two years. This observation is in line with the experience of the literature claiming that currently available medication will hardly be able to normalise brain copper levels. However, observations of clinical variants of Menkes' disease with quite a different outcome and, more importantly, emerging of alternative copper transport pathways might still justify this time-limited therapeutic intervention.
Assuntos
Triagem de Portadores Genéticos , Síndrome dos Cabelos Torcidos/genética , Adenosina Trifosfatases , Adulto , Fatores Etários , Proteínas de Transporte de Cátions , Ceruloplasmina/análise , Pré-Escolar , Cobre/administração & dosagem , Cobre/sangue , Cobre/metabolismo , ATPases Transportadoras de Cobre , Feminino , Deleção de Genes , Histidina/administração & dosagem , Humanos , Lactente , Injeções Subcutâneas , Masculino , Síndrome dos Cabelos Torcidos/sangue , Síndrome dos Cabelos Torcidos/diagnóstico , Síndrome dos Cabelos Torcidos/metabolismo , Síndrome dos Cabelos Torcidos/mortalidade , Síndrome dos Cabelos Torcidos/terapia , Reação em Cadeia da Polimerase , Proteínas Recombinantes de FusãoRESUMO
UNLABELLED: Prader-Willi syndrome (PWS) is considered to be a rare neurogenetic disorder, nevertheless it represents the most common syndromatic obesity. Main features are severe hypotonia in the newborn period with feeding difficulty and failure to thrive in the first few months, and improvement in later infancy. Between 1 and 6 years the development of a marked truncal obesity is observed, sometimes later on reaching a life-threatening degree. Apart from retarded motor development speech ability is also hampered due to dysfunction of oropharyngeal muscles. Moreover, intellectual impairment is observed that leads to mostly moderate learning difficulty due to deficits in short term memory and abstract thinking. The genetic background of PWS is loss of function of a paternally inherited gene cluster on chromosome 15q11.2, therefore representing a paradigm of an epigenetic phenomenon with silencing and activating of genes depending on their parental origin. Together with the Angelman-Syndrome (AS), genetically located in the same region but clinically different PWS was identified as one of the first human disorders to be caused by the mechanism of genomic imprinting. There are some different genotypes in PWS leading to a quite similar phenotype with small differences e.g. in the pigment expression. An early diagnosis is important because the neuromuscular dysfunction improves with appropriate physiotherapy. Even more, dietary programs with periodical calorie restricted meals can counteract development of morbid obesity with subsequent complications of cardiovascular disorders and diabetes. Clinical diagnosis remains difficult especially in the newborn period and is considered mostly because of the marked hypotonia. Today, the availability of molecular testing of loss of function in the paternal inherited PWS candidate gene makes a definitive diagnosis possible as a prerequisite of symptomatic therapy. One of the most recommended therapeutic interventions is the application of recombinant human growth hormone (rhGH) which has been shown to be useful for improvement of length, physical ability and favourable influence on respiratory problems by a lot of clinical studies. SUMMARY: Early diagnosis by means of molecular methods is helpful for comprehensive genetic counseling. It may avoid unnecessary investigations like computed tomography of the brain and muscle biopsy and it enables parents and professionals to start a purposeful therapy. Although it remains a symptomatic tool, GH therapy appears to be useful for most of the patients. Considering the multimorbidity in PWS a multidisciplinary approach seems appropriate for this still mystical condition.
Assuntos
Síndrome de Prader-Willi/diagnóstico , Criança , Pré-Escolar , Deleção Cromossômica , Mapeamento Cromossômico , Cromossomos Humanos Par 15 , Feminino , Genótipo , Humanos , Lactente , Recém-Nascido , Masculino , Fenótipo , Síndrome de Prader-Willi/genéticaRESUMO
We report about the child of a mother with phenylketonuria, which is not suffering from PKU, but is microcephalic and mentally retarded. This retardation is probably a sequel of an intrauterine Hyper-Phenylalanine-status. It is supposed that an intrauterine damage of the offspring even in cases with low Phenylalanine-levels of the mother is possible.
Assuntos
Deficiência Intelectual/genética , Microcefalia/genética , Fenilalanina/efeitos adversos , Fenilcetonúrias/genética , Complicações na Gravidez/sangue , Criança , Cromatografia em Camada Fina , Feminino , Heterozigoto , Humanos , Recém-Nascido , Masculino , Troca Materno-Fetal , Fenilalanina/sangue , Gravidez , Tirosina/sangue , Tirosina/urinaRESUMO
This is a report of the neonatal form of nonketotic hyperglycinemia with rapid progressing neurological symptoms, respiratory distress and seizures. The EEG pattern is characteristic, the ratio of cerebrospinal fluid to plasma glycine abnormally high. The result of cranial computerized tomography demonstrates also in our patient that nonketotic hyperglycinemia joins a growing list of inborn errors of metabolism associated with brain malformations. The consanguinity of parents supports the known autosomal recessive form of inheritance.
Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/sangue , Encéfalo/anormalidades , Consanguinidade , Glicina/sangue , Erros Inatos do Metabolismo dos Aminoácidos/complicações , Erros Inatos do Metabolismo dos Aminoácidos/genética , Aberrações Cromossômicas , Transtornos Cromossômicos , Eletroencefalografia , Feminino , Genes Recessivos , Glicina/metabolismo , Humanos , Recém-Nascido , Linhagem , Tomografia Computadorizada por Raios XRESUMO
Klinefelter's syndrome with karyotype 47,XXY in patients with primary extragonadal germ cell tumors rarely occurs. The endocrinology of Klinefelter's syndrome is changed; elevated beta-human choriomic gonadotropin levels are present. Chemotherapy and thoracic surgery brought complete remission in a patient with lung metastases.
Assuntos
Coriocarcinoma/complicações , Germinoma/complicações , Tumores de Células Gigantes/complicações , Síndrome de Klinefelter/complicações , Neoplasias Pulmonares/complicações , Neoplasias do Mediastino/complicações , Teratoma/complicações , Adolescente , Coriocarcinoma/secundário , Coriocarcinoma/terapia , Terapia Combinada , Germinoma/secundário , Germinoma/terapia , Tumores de Células Gigantes/secundário , Tumores de Células Gigantes/terapia , Humanos , Síndrome de Klinefelter/metabolismo , Neoplasias Pulmonares/secundário , Neoplasias Pulmonares/terapia , Masculino , Neoplasias do Mediastino/patologia , Neoplasias do Mediastino/terapia , Indução de Remissão , Teratoma/secundário , Teratoma/terapiaRESUMO
BACKGROUND: The Ullrich-Turner syndrome (UTS) demonstrates a great clinical variability according to the cytogenetic and molecular genetic findings in various tissues. In few cases the karyotype reveals the presence of an additional Y-bearing cell line which is referred to as a borderline case of mixed gonadal dysgenesis. In this condition, Turner specific stigmata occur in about half of the cases. PATIENT: A 10 year-old girl with short stature and only a few other signs of Turner syndrome and hypertrophic clitoris revealed 45,X/46,X,idic(Yq) mosaicism with 41% 46,X,idic(Yq) cells in a blood lymphocyte culture. METHODS AND RESULTS: Fluorescence in situ hybridisation (FISH) technique, using alpha-satellite Y-chromosome specific probe for locus DYZ3, confirmed the isodicentric character of this structurally abnormal Y chromosome. Polymerase chain reaction (PCR) analysis using primers for eight loci along the Y chromosome including SRY (Sex determining Region, Y gene) were positive for all loci tested, indicating that sequences from the long arm, centromere and most of the short arm of the Y chromosome are present. CONCLUSIONS: As patients with normal or rearranged Y chromosome have an increased risk of developing gonadal neoplasia prophylactic gonadectomy was performed in our patient. No evidence for gonadoblastoma was found on her streak-like gonads, but they showed some evidence of tubular formation. This paper points out the impact of cytogenetic and molecular genetic investigations in the definition of mosaicism in Turner's syndrome.