Characteristics, associations and outcome of partial agenesis of the corpus callosum in the fetus.

OBJECTIVES: To report, in a population of fetuses diagnosed with partial agenesis of the corpus callosum (PACC), the sonographic characterization, incidence of cerebral, extracerebral and chromosomal anomalies, and outcome. In addition, in some of our cases a comparison was made between findings on ultrasound and fetal magnetic resonance imaging (MRI). METHODS: This was a retrospective study of all cases of PACC seen at two referral centers for prenatal diagnosis of congenital anomalies over a 10-year period. The following variables were assessed: indication for referral, additional cerebral and extracerebral malformations, chromosomal abnormalities, and pregnancy and fetal/neonatal outcome. RESULTS: Among 54 cases of fetal agenesis of the corpus callosum detected in the referral centers during the observation period, PACC was diagnosed at prenatal sonography in 20 cases and confirmed at pre/postnatal MRI and necropsy examinations in 19 cases (35%). These 19 constituted the study group. The diagnosis was made in the sagittal planes and in 12 cases it was made prior to 24 weeks. In most cases the indication for referral was the presence of indirect signs of callosal anomalies, such as colpocephaly. In 10 cases PACC occurred in association with other anomalies and in nine it was isolated. MRI was particularly useful for demonstrating some additional cerebral anomalies such as late sulcation, migrational pathological conditions and heterotopia. Regarding pregnancy outcome, of those diagnosed before 24 weeks which had associated anomalies, all except two were terminated. Of the nine cases with isolated PACC, all were liveborn. Follow-up was available in eight, and two of these (25%) showed evidence of significant developmental delay. In our series the outcome of isolated PACC was not better than that of complete agenesis of the corpus callosum reported in other series. CONCLUSIONS: PACC can be diagnosed reliably and characterized in prenatal life. The sonographic sign present in most cases is colpocephaly. Prenatal MRI can be performed to confirm the diagnosis. It is particularly useful to demonstrate some additional cerebral anomalies such as late sulcation, migrational pathological conditions and heterotopia. The relatively poor survival rate is due to the high rate of terminations and associated major anomalies.

Comparative genomic hybridisation in malignant deciduoid mesothelioma.

BACKGROUND: Malignant deciduoid mesothelioma is a rare variant of epithelioid mesothelioma. This tumour generally has poor prognosis, and can be asbestos related. AIM: To identify peculiar genetic changes responsible for critical phases in pathogenesis of malignant deciduoid mesothelioma and their prognostic relevance. METHODS: Comparative genomic hybridisation was carried out in six cases of malignant pleural deciduoid mesothelioma, four sporadic and two familial. All cases were found to be asbestos related. Four patients died during follow-up and the mean survival was 29.5 (SD 14.2, range 12-43) months. RESULTS: Genetic abnormalities were found in all the tumour tissues, the most frequent being chromosomal gains at 1p, 12q, 17, 8q, 19 and 20 and losses at 13q, 6q and 9p. Survival was found to be longer in those patients who presented a smaller number of losses (< or =2) in the tumorous chromosomes. CONCLUSIONS: Although numerous genetic changes are presented by deciduoid mesotheliomas, certain chromosomal regions are preferentially affected. The clinical outcome for this mesothelioma subtype is predicted by the number of losses.

FISH approach to determine cat eye syndrome chromosome breakpoints of a patient with cat eye syndrome type II.

We report a 19-year-old man with craniofacial dysmorphic features, anorectal malformations, eye colobomas, orthopaedic anomalies, and mild neurodevelopmental delay. Cat eye syndrome (CES) was suspected, and confirmed by cytogenetic analysis which showed the presence of a supernumerary bisatellited chromosome, identified by fluorescence in situ hybridization (FISH) as invdup(22). The marker was further analyzed with six BAC clones located at the 22q11.1 and 22q11.2 regions; this analysis allowed correct assignment at low copy repeat 4 on chromosome 22 (LCR22-4) of the two breakpoints, confirming the presence of a CES chromosome type II. The patient's phenotype is considered in the light of the cytogenetic, and FISH investigations results and other patients reported in literature. Molecular definition of the breakpoints at the LCR22-4 copy confirms the role of different chromosome 22-specific LCRs in CES chromosomes generation, as well as in other chromosome 22 germ line rearrangements. Our report confirms that, unlike other conditions, i.e. the invdup(15) bisatellited dicentric marker, the CES phenotype does not appear to correlate with the size of the marker chromosome. Additional cases are necessary to be able to draw more specific genotype-phenotype correlations and to determine the outcome of patients with CES, especially when this rare condition is diagnosed in prenatal age.

[''Isolated'' single umbilical artery: incidence, cytogenetic abnormalities, malformation and perinatal outcome]. / Arteria ombelicale singola "isolata": incidenza, anomalie citogenetiche, malformazioni ed outcome perinatale.

AIM: The aim of the study was to 1) evaluate the gestational age at diagnosis and the incidence of single umbilical artery in an unselected population of 3750 pregnant women; 2) identify its association with malformations and/or karyotype aberrations in pre/postnatal age; 3) evaluate the fetal-neonatal outcome; 4) investigate the likelihood that a fetus might be affected by a cytogenetic abnormality even in presence of an apparently ''isolated'' single umbilical artery. METHODS: Transabdominal ultrasound of the umbilical vessels and histological confirmation at birth. In presence of single umbilical artery an accurate prenatal ultrasound assessment, karyotyping (pre/postnatal), and clinical follow-up after birth were performed. RESULTS: The incidence of single umbilical artery in our population resulted 1.07% (40/3750), being ''isolated'' in 40% of cases. The diagnosis of chromosomal aberration associated with single umbilical artery was made in 6 cases (15%), while structural fetal abnormalities in absence of causal chromosomal anomalies were present in 9 cases (22.5%), with syndromic patterns in 3 of them. In 2 cases with chromosomal anomalies the single umbilical artery was apparently ''isolated'' at the ultrasound examination between the 17th and the 22nd week of gestation. Excluding 4 terminations of pregnancy, the perinatal mortality percentage resulted 25% (9/36); similarly, fetal growth retardation was present in 25% of cases (9/36). CONCLUSIONS: The incidence of single umbilical artery in our population confirms that this fetal vascular anomaly is frequently identified in pregnancy. In the light of our cases and data in the literature it is evident that diligent surveillance in prenatal age and accurate clinical follow-up after birth are mandatory when a single umbilical artery has been diagnosed. Finally, the possibility, even if rare, that even when the single umbilical artery is apparently ''isolated'', a chromosomal aberration might be present (1/24 of our ''isolated'' cases) should be considered when addressing correct counselling to the couples.

Characteristics, associations and outcome of absent pulmonary valve syndrome in the fetus.

OBJECTIVES: To assess in a population of 21 fetuses diagnosed with absent pulmonary valve syndrome (APVS) the accuracy of prenatal diagnosis, the incidence of extracardiac and chromosomal anomalies and the perinatal outcome. METHODS: This was a retrospective observational study of 21 fetuses with a confirmed diagnosis of APVS. All of them underwent fetal echocardiography and a detailed anatomical scan. Karyotyping was performed in 20/21 cases, with fluorescent in-situ hybridization analysis to detect the 22q11 microdeletion performed in 16/21 cases. The following variables were retrieved from databases and evaluated: indication for referral, gestational age at diagnosis, presence of cardiomegaly, branch pulmonary dilatation, associated anomalies or intrauterine growth restriction, and fetal/neonatal outcome. Autopsy reports and postnatal surgical/medical files were available for confirmation in all cases. RESULTS: Prenatal diagnosis of APVS proved correct in all cases, with only three cases occurring not in association with tetralogy of Fallot. Additional cardiovascular anomalies were present in five cases (24%). Extracardiac anomalies were found in nine cases (42.8%), and were associated with chromosomal anomalies in five cases (24%). The 22q11 microdeletion was present in 4/16 cases (25%). Fetal/neonatal outcome was as follows: nine terminations of pregnancy, three intrauterine deaths, six postnatal deaths. The remaining three (14.3%) neonates were alive after surgery. Cardiomegaly and marked branch pulmonary dilatation were present in 16 and 15 cases, respectively, and were associated with bronchomalacia in virtually all cases. CONCLUSIONS: APVS can be reliably diagnosed and characterized prenatally. The association with major chromosomal anomalies or 22q11 microdeletion is consistent with previous findings. The relatively poor survival rate is due to the high rate of terminations, associated genetic anomalies and bronchomalacia. Bronchomalacia is present in the overwhelming majority of cases featuring cardiomegaly and marked branch pulmonary dilatation.

Clinical, cytogenetic, and molecular characterization of a patient with a de novo interstitial 22q12 duplication.

We report a 19-year-old woman with minor craniofacial anomalies, mild mental retardation, and foramina parietalia permagna (FPP) (OMIM 168500). Cytogenetic analysis showed a de novo interstitial chromosome 22 long arm duplication. FISH with a panel of chromosome 22q12-q13 bands-specific BAC clones refined the cytogenetic investigation, and restricted the duplicated segment to the q12 region. Mutation analysis of FPP genes identified an insertion mutation in the ALX4 gene (344insC) in the proband and her father with loss of function of the gene. The patient's phenotype is considered in the light of the results of the cytogenetic, FISH, and molecular investigations, and her features are compared with those of other patients with similar duplications. Finally, variable phenotypic findings due to different 22q duplicated chromosomal segments are discussed. Our report indicates that 22q12 interstitial duplications are associated with craniofacial anomalies and mild mental retardation, while life threatening malformations are usually not present. Although these phenotypic changes are common and non-specific, molecular study of our patient established more precise relationships between clinical findings and 22q duplicated region(s). This approach fosters better counseling of the families of patients with newly diagnosed, similar duplications.

Common arterial trunk in the fetus: characteristics, associations, and outcome in a multicentre series of 23 cases.

OBJECTIVE: To assess the accuracy of prenatal diagnosis, the incidence of extracardiac and chromosomal anomalies, and the perinatal outcome in a population of fetuses with common arterial trunk (CAT). DESIGN: Observational study of 23 fetuses from three referral centres with a confirmed diagnosis of CAT. All underwent fetal echocardiography, detailed anatomical scanning, and karyotyping. In 19 cases, FISH analysis was done to detect 22q11 microdeletion. The following variables were evaluated: gestational age at diagnosis, anatomical variants of the CAT, presence of extracardiac and chromosomal anomalies, pregnancy, and fetal-neonatal outcome. Necropsy reports and postnatal files were available for confirmation of the prenatal diagnosis in all cases. RESULTS: The prenatal diagnosis proved correct in 23 of 24 cases, the last being pulmonary atresia with ventricular septal defect (PAVSD). A second cardiovascular anomaly was present in eight cases (34.8%); extracardiac anomalies were found in 10 (43.4%). FISH analysis showed 22q11 microdeletion in six of 19 cases (31.6%). Outcomes were as follows: eight terminations of pregnancy (34.8%), two intrauterine deaths (8.7%), five postnatal deaths (before or after surgery) (21.7%); the remaining eight neonates (34.8%) are alive and thriving after surgery (six) or awaiting surgery (two). CONCLUSIONS: CAT can be reliably diagnosed and characterised in prenatal life, although differentiation from PAVSD may be challenging. The association with chromosomal anomalies is consistent (8.7%), but there is a higher risk of 22q11 microdeletion (31.6%), in agreement with postnatal studies. The relatively poor survival rate (34.8%) reflects the high rate of terminations and the unfavourable cardiac anatomy in some cases.

FISH and cytogenetic characterization of a terminal chromosome 1q deletion: clinical case report and phenotypic implications.

We report a 24-year-old woman with minor facial anomalies, mental retardation, seizures, and partial agenesis of the corpus callosum. Cytogenetic analysis showed a de novo terminal chromosome 1 long arm deletion. FISH with a panel of chromosome 1q42-qter bands-specific BAC and YAC clones located the breakpoint at the 1q42-q43 junction, with monosomy restricted to the 1q43 and 1q44 bands. The changing craniofacial phenotype of this patient with age is described as part of the del(1)(q) syndrome natural history. The patient's features are compared with those of other patients with similar deletions, and variable phenotypic findings due to different deleted chromosomal segments are discussed.

Molecular and cytogenetic characterization of an azoospermic male with a de-novo Y;14 translocation and alternate centromere inactivation.

BACKGROUND: Y-autosome (Y/A) translocations have been reported in association with male infertility. Different hypotheses have been made as to correlations between Y/A translocations and spermatogenetic disturbances. We describe an azoospermic patient with a de-novo Y;14 translocation: 45,X,dic(Y;14)(q12;p11). METHODS AND RESULTS: Cytogenetic, fluorescent in-situ hybridization (FISH) and molecular studies have been performed. A 14/22 (D14Z1/D22Z1) centromere and a Y centromere (DYZ1) probe both showed a signal on the translocation chromosome, confirming its dicentricity. Each copy of the translocation chromosome had only one primary constriction, with inactivation of the Y centromere in most (90%) of the cells. The 14 centromere was inactive in the remaining cells (10%). FISH and molecular deletion mapping analysis allowed acute assignment of the Yq breakpoint to the junction of euchromatin and heterochromatin (Yq12), distal to the AZF gene location (Yq11). CONCLUSIONS: This study supports the hypothesis that in Y/A translocations infertility might be related to meiotic disturbances with spermatogenetic arrest. In addition, sex chromosome molecular investigations, performed on single spermatids, suggest a highly increased risk of producing chromosomally abnormal embryos.

Molecular and cytogenetic characterisation of an unusual case of partial trisomy/partial monosomy 13 mosaicism: 46,XX,r(13)(p11q14)/46,XX,der(13)t(13;13)(q10;q14).

A female infant with multiple malformations and mental retardation was noted to have a rare de novo chromosome abnormality involving mosaicism with two cell lines, one with a ring chromosome 13, and the other with partial trisomy 13 owing to a complex rearrangement. Cytogenetic examination excluded the presence of a t(13q;13q) cell line and showed a cell line with a marker chromosome containing two chromosome 13 long arms joined together after deletion of a part (q11-->q14) of one of them. In addition, the absence of a cell line with two normal chromosomes 13 or a cell line with a t(13q;13q) implies that the ring (13) and the marker (13) arose from a single event at the first cleavage division. The two cell lines were present in different proportions in both peripheral blood lymphocytes and skin fibroblasts. The results of microsatellite characterisation clearly indicate the paternal origin and the absence of recombination, supporting the postzygotic origin of both the ring and the marker chromosome.