BACKGROUND:Li-Fraumeni syndrome greatly increases the risk of developing several types of cancer and is usually caused by TP53 germline mutations. Predictive testing of at-risk family members is only offered after a complex genetic counselling process. Recently the clinical implementation of array comparative genomic hybridisation (CGH) has revolutionised the diagnosis of patients with syndromic or non-syndromic mental retardation and has evolved to a routinely performed high resolution whole genome scan.METHODS AND RESULTS:When using array CGH to identify the cause for mental retardation in a 7-year-old child we found a submicroscopic de novo deletion of chromosome 17p13.1, which includes several genes likely to be causative for her phenotype, and also of TP53.CONCLUSION:Thus, array CGH resulted in an unintended predictive diagnosis of an increased tumour susceptibility as observed in Li-Fraumeni syndrome.

A great number of syndromes and inborn errors of metabolism associated with impaired development have been observed, but the aetiology of mental retardation remains unclear in a considerable proportion of cases. Here, we present the clinical and molecular data from a patient with a new de novo subtelomeric deletion on chromosome 20 [46,XX.ish del(20)(qter‐)]. For further refinement, bacterial artificial chromosome clones are used. The deletion spans exactly two genes called MYT1 and PCMTD2. Both genes play an important role in myelination and regulating neural differentiation. Loss of these two genes seems to be responsible for the severe mental retardation and mild facial dysmorphic features in our young patient. It might show the phenotypic picture of this specified deletion.

We describe a 4-year-old boy with various facial dysmorphic features such as downslanting palpebral fissures, ptosis, hypertelorism, broad nasal bridge, small and low-set ears, broad philtrum, and micrognathia. In addition, profound mental retardation, myopia, muscular hypotonia as well as genital and cardiovascular abnormalities are also present. Refinement of the breakpoints by cytogenetic techniques, in particular the increase of banding resolution in conventional cytogenetic analysis, has enabled the correct diagnosis, as proven by fluorescence in situ hybridisation (FISH) using whole chromosome painting and single copy probes. We were able to demonstrate an unbalanced translocation that the patient inherited from his father resulting in a submicroscopic monosomy 16p13.3 and a trisomy 2p24.2-pter.

We report on a currently six-year-old patient with a de novo complex chromosome rearrangement (CCR) involving chromosomes 2 and 12. A translocation 2;12 that appeared to be reciprocal after standard banding turned out to be a complex event with seven breaks after molecular cytogenetic analyses. Array CGH analysis showed no imbalances at the breakpoints but revealed an additional microdeletion of about 80 kb on chromosome 11. The same deletion was also present in the phenotypically normal father. The patient showed relatively mild mental retardation, defined mainly as impaired speech development (orofacial dyspraxia) and psychomotor retardation. In addition, mild dysmorphic facial features like hypertelorism, a prominent philtrum and down-turned corners of the mouth were observed. We narrowed down all breakpoint regions to about 100 kb, using a panel of mapped bacterial artificial chromosome (BAC) clones for fluorescence in situ hybridization (FISH). BACs spanning or flanking all seven breakpoints were identified and no chromosomal imbalances were found consistent with the array CGH results. Our investigations resulted in the following karyotype: 46,XY,t(2;12)(2pter-->2p25.3::2p23.3-->2p25.2::2p23.3-->2p14::2q14.3-->2p14::2q14.3-->2q14.3::12q 12-->12qter;12pter-->12q12::2p25.3-->2p25.2::2q14.3-->2qter).

We report on a now 4 ½ year old female patient, who has been suffering from severe epilepsy from the age of 6 weeks onward. Beside mild hypertrichosis no stigmata or dysmorphic signs were detected. Cranial imaging, routine CSF analysis and biochemical screening for amino- and organoacidopathies were normal. Seizures initially were therapyresistant to pyridoxine, phenobarbitone and valproate but by age 3 years could be controlled by a low dose combination of valproate, clonazepam and topiramate. Developmental delay was evident from early infancy with marked delay of motor milestones and severe mental retardation. At the age of 4 years she had poor visual contact, absent speech, insensitivity to pain and generalized dyspraxia. Mild muscular hypotonia with scoliotic posture of the upper spine was present, deep tendon reflexes were preserved. EEG showed a monomorphic pattern of rhythmic high-voltage alpha/theta activity with lack of fronto-occipital differentiation and of epileptic discharges. Motor nerve conduction velocity as well as cranial MRI were normal.

Williams-Beuren syndrome is a genetic disorder caused by a heterozygous deletion at 7q11.23. The present report describes a female patient with Williams-Beuren syndrome combined with caudal regression syndrome and two forms of coagulopathy. Besides the typical developmental abnormalities such as mental and growth retardation, a distinctive facial appearance, and cardiovascular anomalies, our patient showed fusion of fourth and fifth lumbar vertebra and a sacrococcygeal agenesis. Blood coagulation tests revealed a deficiency of coagulation factor XI and XII. Magnetic resonance imaging angiography showed multiple vascular stenoses mainly in the abdominal aorta and its major branches as a consequence of the insufficient elastin gene. Previous reports identified a deletion of HLXB9 as a possible genetic cause of the caudal regression syndrome, which could not be identified in the present case. This unusual combination of the above-mentioned genetic disorders has not been published so far.

The high pathogenetic relevance of genetic factors in schizophrenia is beyond doubt based on the findings of epidemiological studies. By means of a complex mode of transmission, it is likely that several genes with weak to moderate effect jointly constitute a genetic basis for a vulnerability to schizophrenia that may well vary for different individuals. Other organic and psychosocial factors also play an individually different -- in some cases significant -- role in terms of pathogenesis, as a result of which an oligogenic/polygenic multifactor model is assumed from the standpoint of aetiopathogenetics. Molecular genetic methods consist in linkage analyses and association analyses. Positive linkage findings accumulate particularly for the chromosomes 1q, 6p, 8p, 13q and 22q. By themselves, individual mutations contribute little to the range of schizophrenic feature characteristics, it was not possible -- irrespective of some subtypes -- to replicate genes of major effect. From the large number of possible candidate genes, although studies on DRD3, DRD2 and HTR2A produced positive results, the magnitudes of effect were low. The findings for alleles of dysbindin, neuregulin 1, DAO, COMT, PRODH, ZDHHC and DISC are less clear. The search for schizophrenia-relevant mutations is hampered by the possibility of a heterogeneous phenotype of schizophrenia in case of a homogeneous genotype as much as by the possibility of inter-individually homogeneous phenotypical characteristics in case of schizophrenia-relevant heterotype in the genome. With the aid of the concept of endo-phenotypes, based on neurobiological phenomena, it might be possible to take a more direct approach that leads from relevant mutations to the risk of schizophrenias. However, replacing schizophrenic alienation with neurobiological aspects leads to difficulties in explaining these complex disorder profiles. Schizophrenic diseases require an explanatory approach that also incorporates personality and developmental psychological aspects from the outset, if the aim is not to restrict type of schizophrenic disease exclusively to loci of molecular genetic changes.

Autism is a relatively common and heterogenous neuropsychiatric disorder characterized by reduced social and interindividual contacts and interactions. Autism usually starts in early childhood. Complete absence of eye contact and speech can be observed in severe forms of autism. Due to problems of defining the wide spectrum of children with the triad of impairments of social interaction, communication, and imagination, the prevalence of autismhas been reported to vary from 2 to 64 per 10,000 [Smalley et al., 1988; Chakrabarti and Fombonne, 2001]. It cannot be ruled out that prevalence rates have increased overtime. Studies of familial cases have demonstrated that genetic factors are involved in the etiology of autism. A number of balanced and unbalanced chromosomal aberrations have been found to be associated with autism [Gillberg, 1998; Wassink et al., 2001; Shao et al., 2003]. In several monogenic disorders, like fragile X syndrome [MIM 309550] and Rett syndrome [MIM no. 312750], it has been possible to identify a single gene that can lead to autistic-like behavior in some affected individuals. However, nomajor gene for autism has yet been identified. In this study we describe a reciprocal translocation t(5;18)(q33.1;q12.1) that occurred de novo in a 13-year-old boy with autism and psychomotor retardation and only minor additional anomalies or dysmorphic features. Neither chromosomal breakpoint has beenmentioned in previous reports of cytogenetic aberrations seen inpatientswith autistic behavior. Our patient (Fig. 1) was born as the son of unrelated parents after an uncomplicated pregnancy and delivery in the 40th week of gestation. Birth weight was 4,130 g (>90th centile), length 54 cm (>90th centile), and head circumference (OFD) 37 cm (>90th centile). Apgar score was 9/10/10. Maternal and paternal ages were 21 and 22 years, respectively. Three days after birth the patient was hospitalised for 12 days to treat an otherwise uncomplicated bronchopneumonia. The following neonatal period was normal and routinely performed pediatric examinations did not show obvious anomalies up to the age of 10 months. At this age he started to walk. However, right from the very beginning, only toe walking was observed, and at 18 months stereotypic hand movements were noticed more frequently. There was no development of speech and language. In the following months he became more difficult to handle, was very shy, and started crying frequently for no apparent reason. Missing or grossly reduced eye contact and presence of stereotypical hand movements became evident. It took until theage of 26months for psychomotor symptoms, and especially mental retardation to be diagnosed. Subsequently he received intensive special intervention and regular training at the kindergarten. Finally, at 31⁄2 years of age, the diagnosis of autism was made, because of the typical autistic features (described below). To improve his cognitive andmotor skills, he was integrated into an intensive special training program.His initial response was very aggressive. However with consequent and repeated positive and negative feedback, he slowly began to achieve simple tasks. At re-evaluation at 12/12, in addition to the clinical examination, the questionnaire Autism Diagnostic InterviewRevised Schedule [ADI-R; Lord et al., 1994] and a systematic observation using the Autism Diagnostic Observation Schedule [ADOS; Lord et al., 1989] were applied. We have no IQscore because the boy is not cooperative. The results from the ADI-R, which was performed with the mother, show qualitative deficits in all fields: interactive reciprocal social interaction, communication and language, repetitive, restrictive, and stereotyped behavior as well as abnormal development before the age of 36 months. In all functions the score was higher than the ‘‘Cut-Off,’’ thus a postive diagnosis of ‘‘autism’’ was made. The ADOS-Module 2 was performed in the patient’s home environment with the assistance of a nurse. The test could not be applied rigorously, because the child showed extreme restlessness, and only short episodes of interactive behavior could be observed. The child did not show any creative game and no reciprocity. He consistently responded when the examiner called his name. His conversation was limited to 2-item phrases such as ‘‘please chocolate, please juice, Margit come!’’ The child understands short precise sentences and most often expresses needs by one-word-items. He accepts children trying to get in contact with him, but prefers contact with adults (parents, nurse, and other well-known persons). Usually he does not establish contactwith other children.He does not play with other children who contact him. He shows stereotyped behavior, knocking with one object or clapping one hand against the other, or turning a straw or pencil. Aggression towards others is seen rarely, sometimes the child shows autoaggression. His passions are movie pictures. Uponphysical examinationat 13yearshisheightwas171cm (>90th centile), weight was 51 kg (75–90th centile), and head circumference was 57 cm (>97th centile). Head circumference of the parents was normal (father: 56 cm; mother 54 cm). Based on our clinical evaluation and on pediatric records he shows normal morphology with very minor dysmorphic signs like slight downslanting palpebral fissures, deep set eyes, and protruding teeth. Mainly on his left upper back he showed several large hyper pigmented cutaneous spots with irregular margins not following the lines of Blaschko. Wood lamp examination did not show any additional anomaly of pigmentation. Gynecomastia was noticed but his pubertal development, currently Tanner P3-4, G 3 is only slightly delayed. He attends a school for the mentally disabled. No anomalies of inner organs, as determined by ultrasound and X-rays, nor of brain, Grant sponsor: Oesterreichische Nationalbank (to E.P.); Grant number: 9522.

Interstitial deletions of the long arm of chromosome 14 are infrequent. Molecular and clinical studies on patients with deletions involving 14q11.2-q21 have recently been reported.1 Most of these deletion patients share common clinical signs, such as midline defects of the central nervous system, feeding problems, growth abnormalities, hypotonia, developmental delay, mental retardation, and craniofacial anomalies.1 Here we present the phenotypic, cytogenetic, and molecular genetic findings of a 2½12 year old boy with a 14q12-q13.1 deletion. To our knowledge this is the second case described of a patient with a deletion of less than 3.5 Mb within chromosome bands 14q12-q13.1. Using the genomic sequence between markers D14S1060 and D14S286, we have constructed a transcription map of the genomic interval deleted in our patient. Our proband (fig 1) is the 40 week product of a second, uncomplicated pregnancy and delivery. Maternal age was 27 years. Birth weight was 4435 g (>90th centile), length 55 cm (>90th centile), and head circumference 34 cm (10th-25th centile). Apgar score was 7/9/10. The neonatal period was complicated by pneumonia, treated with parenteral antibiotic therapy over 10 days. Besides relative microcephaly, hypertelorism, epicanthic folds, a long and flat philtrum, hypodontia, laterally placed, hypoplastic mamillae, second degree hypospadias, bifid scrotum, and bilateral cryptorchidism were noticed. Cranial ultrasound was normal; ultrasound of the kidneys and pelvic region showed bilateral second degree hydronephrosis, and both testes were visible in the inguinal region. Screening for connatal infections (toxoplasmosis, rubella, cytomegalovirus, and parvovirus B19) was negative. Psychomotor development was severely impaired from early infancy. Lack of vision was evident at 3 months and, apart from head control, no gain of motor milestones or social contact was achieved until the age of 29 months. Muscle tone of the trunk was decreased while it was increased and dystonic in the upper and …

Objective The purpose of the study was to assess the feasibility of analysis of fetal nucleated red blood cells (NRBC) present in the maternal circulation by laser-scanning cytometry.Methods CD71-positive cells were obtained by magnetic cell sorting of peripheral blood of pregnant women after density centrifugation. Immunofluorescence for the Hbgamma-chain was combined with fluorescent staining of DNA (TO-PRO-3) and fluorescence in situ hybridization (FISH) with a Y-chromosome specific probe. The cells were scanned on a slide using a laser-scanning cytometer (LSC). Events double positive for Hbgamma and TO-PRO-3 were relocated and their morphology and FISH reactivity were visually assessed. Determination of male fetal sex with LSC was compared with findings from amniocentesis.Results In 8/15 pregnancies with male fetuses and in 0/9 with females (apart from one case with a male/female twin pregnancy), we detected Y-chromosome-positive NRBC. In pregnancies with female fetuses, Y-chromosome-positive cells other than NRBC were found in all women who had previously given birth to male babies, whereas women with no abortion and no male babies in their history did not present with Y-chromosome-positive non-NRBC.Conclusion On the basis of automatic relocation of once-defined cells of fetal origin from the current pregnancy, laser-scanning cytometry is likely to facilitate repeated (poly-)FISH analysis and single-cell PCR for noninvasive prenatal diagnosis. Copyright (C) 2003 John Wiley Sons, Ltd.

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder with an estimated birth incidence of 1 in 2500 and marked variability of expression. The hallmark symptoms of the fully manifested disease encountered in nearly all patients are cutaneous neurofibromas, cafe au lait spots, axillary freckling, and Lisch nodules. Other common manifestations are bone dysplasias, scoliosis, vasculopathy, and learning disabilities. NF1 patients also suffer from an increased risk of specific tumour types like plexiform neurofibromas, neurofibrosarcomas, optic gliomas, other CNS tumours, phaeochromocytomas, juvenile xanthogranuloma, and juvenile myeloid leukaemia. Mutations of the NF1 gene at 17q11.2 encoding neurofibromin are the molecular basis of the disease. Neurofibromin contains a GTPase activating domain and is a negative regulator of Ras GTPases. Homozygous inactivation of neurofibromin is associated with a dysregulation of Ras mediated signalling pathways and tumorigenesis in NF1 patients.1 More than 70% of the germline mutations are protein truncating and are distributed throughout the coding region.2–4 No distinct genotype-phenotype correlation concerning type and position of the mutations has been established, apart from patients with microdeletions of the NF1 gene region, which are associated with a more severe clinical phenotype and facial dysmorphism. This was recognised very early and confirmed by several studies.5–9 Molecular characterisation of the deletion boundaries showed that non-allelic recombination between two highly homologous sequences separated by ~1.5 Mb eliminates 14 genes together with the NF1 gene during germ cell development.10–14 These 60–85 kb spanning low copy repeats are derived from segments of the WI-12393 gene and contain sequences with homology to chromosome 19. The structure of the NF1 gene region at 17q11.2 is further complicated by other duplicated sequences, such as pseudogene exons of the SMURF2 and the KIAA0160 genes.10,15 Up to now, homologous recombination between these duplicated sequences during mitotic …

We report a 2-year-old boy with Prader-Willi Syndrome (PWS) caused by a deletion of the PWS critical region as a result of an unbalanced translocation t(3;15). Additional features, including central visual impairment, relative macrocephaly, retrognathia, preauricular tags, and bilateral club-feet, were noticed. The extension of the deletion was determined by fluorescence in situ hybridization (FISH) analysis using 11 region-specific YAC clones. Nine YACs were found to be deleted, allowing us to determine that the deletion is larger than in patients with typical PWS deletions. The karyotype of this patient can thus be designated: 45,XY,-15,der(3)t(3;15)(qter;q14).ish der(3)t(3;15)(qter;q14) (wcp3+,wcp15+,D15S10-,PML+,D15Z1-,D3S4560+,801_f_9x1, 815_e_6x2) de novo. Molecular analyses using seven polymorphic markers helped to narrow down the breakpoint between marker ACTC.PC3 and the distal end of the YAC 815_e_6. These results provide evidence that haploinsufficiency for genes in 15q13-q14, not affected in common PWS deletions, is associated with the additional features found in the patient, including a central visual impairment.

Trisomy 18 is the second most frequent autosomal aneuploidy affecting about 1 in 8,000 new-borns. Similar to trisomy 13 more than 90% of the patients die within the first year. Main causes of death are failure of vital organ function, in most cases of brain, heart, kidney, and gut, sometimes combined with severe infections. The degree to which essential organs are affected at birth and the clinical course differ considerably. Unknown genetic factors and various environmental effects are most likely involved. A less severe course of Edwards syndrome can be caused by a partial trisomy due to a deletion of the extra chromosome 18 or somatic mosaicism with a trisomic and a normal cell-line in the patient. In this report conventional chromosome analysis, FISH, and QF-PCR have been performed on a 19-year-old female patient with trisomy 18 to investigate a large number of cells including non-mitotic cells from various different tissues. This study supports evidence for an apparently pure form of trisomy 18 in this "long-living" patient with Edwards syndrome.

frog) 205 Mixophyes fasciolatus, M. schevilli (Australian ground frog) 239 mouse 7, 51, 62, 95, 100,

We have mapped the LAT gene by radiation hybrid mapping and fluorescence in situ hybridization to chromosome 16p11.2. The complete cDNA sequence of LAT was generated using assembled sequences of cDNA fragments already available. BLAST analysis using the cDNA sequence led to the identification of BAC clone CTB-134H23 (GenBank Accession No. AC112166). The genomic structure of the human LAT gene consists of 11 exons, encompassing 5.7 kb. Alternative splicing variants were identified.