1/608. Partial monosomy 22 as the result of an unbalanced translocation 5:22 in a patient with cri-du-chat syndrome. A 2-year-old boy with features suggestive of cri-du-chat syndrome had a complex karyotype: 45,XY,--22,5p--,t(5p:22q). Clinical symptoms were catlike cry in early infancy, severe mental and motor retardation, failure to thrive, hypertelorism, antimongoloid slant of the eyes, ptosis of the eyelids, epicanthus, micrognathia, dermatoglyphics abnormalities, and partial syndactyly between 2nd and 3rd toes. ( info) |
2/608. Intrachromosomal triplication of 2q11.2-q21 in a severely malformed infant: case report and review of triplications and their possible mechanism. A female fetus with brain malformations, multicystic kidneys, absence of the right thumb, and a posterior cleft of palate was delivered at 32 weeks of gestation. Cytogenetic studies including FISH showed a novel intrachromosomal triplication of the proximal long arm of chromosome 2 (q11.2-q21), resulting in tetrasomy for this segment. The middle repeat was inverted. At least 11 patients with intrachromosomal triplications have been reported, mostly involving chromosome 15q. The mechanism involved in formation of these rearrangements is compatible with U-type exchange events among three chromatids. ( info) |
3/608. sex chromosome pentasomy (49,XXXXY) presenting as cystic hygroma at 16 weeks' gestation. The pentasomy 49,XXXXY is one of the rarest sex chromosome defects, occurring with an estimated incidence of 1 in 85 000 male births. This condition is associated with pre- and postnatal growth deficiency, severe mental retardation, hypogenitalism, and other skeletal, facial and cardio-vascular anomalies. In this report we present such a case diagnosed prenatally by chorionic villus sampling after the ultrasound detection of cystic hygroma at 16 weeks' gestation. Although the prenatal diagnosis of cystic hygroma and its association with aneuploidy has been documented in numerous reports, sex chromosome aneuploidy, other than the 45,X karyotype, accounts for only 0.3 per cent of cases. ( info) |
4/608. trisomy 2 in an acardiac twin in a triplet in-vitro fertilization pregnancy. A case is reported of twin reversed arterial perfusion (TRAP) sequence in a triamniotic dichorionic triplet pregnancy conceived by in-vitro fertilization which was diagnosed at 25 weeks of gestation by colour Doppler sonography. It highlights the risk of monochorionicity-associated morbidity in multiple pregnancies obtained by assisted conception and stresses the importance of chorionicity determination by early ultrasound examination. cytogenetic analysis of skin from the acardius showed trisomy 2 in all cells, whereas the karyotype in the monochorionic triplet was normal. This is an example of heterokaryotypic monozygotism where the chromosomal abnormality must have occurred during the early cleavage divisions. aneuploidy as a possible aetiological factor of TRAP sequence is discussed. ( info) |
5/608. An extra idic(21)(q22.1) in a child with some features of Down's syndrome. A 30-month-old boy with mental retardation, hypotonia, joint hyperlaxity, Brushfield spots, open mouth, distal axial triradius t", and ulnar loops on both forefingers was found to have a 47,XY, psu idic(21)(q22.1).ish psu idic(21)(q22.1)(D13Z1/D21Z1 ,ETS2-) karyotype. The patient's phenotype, with only some Down's syndrome (DS) features, is probably related to his disomy for most or all of the critical region 21q22.2 q22.3 and agrees with the current notion that certain DS features may also result from 21q proximal duplications. The phenotypical comparison with 2 other patients with a similar extra idic(21) reveals some discrepancies, which may be related to the inherent clinical variability of similar imbalances: yet, a real difference between the tetrasomic segments cannot be excluded. Noticeably, all 3 patients with 21q proximal tetrasomy did not have cardiac defect and exhibited none or just one out of the five other DS phenotypic features attributed to a single gene or cluster on distal 21q22. ( info) |
6/608. Angiosarcoma of the testis. A primary angiosarcoma of the testis in a 74-year-old patient was a highly anaplastic epthelioid angiosarcoma, which was positive for endothelial markers immunohistochemically. The tumour was unrelated to testicular germ cell neoplasm; the patient had received no previous radiation or chemotherapy. ( info) |
7/608. Unilateral aneuploid dedifferentiated acinic cell carcinoma associated with bilateral-low grade diploid acinic cell carcinoma of the parotid gland. A dedifferentiated acinic cell carcinoma (AciCC) of the right parotid gland with lymph node metastases occurred in a 36-year-old woman. The tumour was associated with a bilateral well-differentiated AciCC. The two components of this tumour had different (high and low) proliferative activity measured by Mib-1 and different (aneuploid and diploid) dna content. Despite the presence of a high-grade component, TP53 mutations, microsatellite instability (MSI) and/or loss of heterozygosity (LOH) at the p53 locus were not detected. Although the follow-up of the patient is very short, the aggressiveness of the tumour is shown by a recurrence in the right parotid within 4 months and by the rapid development of regional metastases. ( info) |
8/608. Isolated tetrasomy 8 in minimally differentiated acute myeloid leukemia (AML-M0). tetrasomy 8 as a sole anomaly in hematological disorders is relatively rare. To the best of our knowledge, only 19 such cases have been described in the literature to date. Of them, acute myeloid leukemia (AML) in 13 (M1, one; M2, three; M4, one; M5, eight), acute lymphoblastic leukemia(ALL) in one, myelodysplastic syndrome(MDS) in 3, polycythemia vera(PV) and myelofibrosis(MF), one case each. Their median survival was 20 weeks. Here, we report the first case of a 29-year-old man with minimally differentiated AML (AML-M0) displaying a tetrasomy 8 clone. immunophenotyping showed positivity with CD33, CD34 and intracellular MPO, but all lymphoid markers tested were negative. Conventional cytogenetics of bone marrow cells showed 84.9% of metaphases with tetrasomy 8 in addition to 15.1% with normal diploidy. However, fluorescence in situ hybridization(FISH) using a centromeric probe specific for chromosome 8 revealed trisomy 8 in 14.2% of interphase nuclei besides tetrasomy 8 in 82.4%. The patient died four weeks after diagnosis without therapy. In conclusion, these findings suggest that tetrasomy 8 is associated with a heterogeneous group of myeloid disorders and heralds a bad prognosis. It may be a consequence of clonal evolution of trisomy 8. ( info) |
9/608. Sperm analysis in a subfertile male with a Y;16 translocation, using four-color FISH. Sperm analysis was performed in a male with oligoasthenoteratozoospermia (OAT) and a reciprocal t(Y;16) (q11. 21;q24), using four-color FISH. Intracytoplasmic sperm injection (ICSI) treatment in this patient had resulted in the birth of one chromosomally balanced and two chromosomally normal children. To assess the risk of having a chromosomally unbalanced conception after ICSI, morphologically normal spermatozoa were studied with a set of probes allowing detection of all segregation variants. There were 51% normal or balanced sperm cells. The fraction of sperm products resulting from alternate and adjacent I segregation was 87%, 12% were products of 3:1 disjunction, and the other 1% had other types of aneuploidy. If morphologically abnormal cells were also included in the FISH analysis, nearly 90% of all the spermatozoa were unbalanced. We conclude that although the majority of males with a Y/autosome translocation are infertile due to azoospermia, our patient produces sufficient morphologically and chromosomally normal spermatozoa to have chromosomally normal or balanced offspring after ICSI. Assuming that ICSI with an unbalanced spermatozoon from this patient would result in a nonviable embryo in many cases, the combination of in vitro and subsequent in vivo selection probably results in a risk of unbalanced offspring of much less than 50%. Hence, FISH studies on the sperm of translocation carriers are useful for estimating the risk of having unbalanced offspring after ICSI and in understanding the mechanisms underlying infertility in such carriers. ( info) |
| mosaicism for trisomy 17 in amniocyte cultures is a rare finding, whilst postnatal cases are exceptional. In order to gain insight into the possible effects of the distribution of the trisomic line and of uniparental disomy (UPD) on embryofoetal development, we have performed follow-up clinical, cytogenetic and molecular investigations into three newly detected prenatal cases of trisomy 17 mosaicism identified in cultured amniotic fluid. In the first case, the pregnancy ended normally with the birth of a healthy girl, and analysis of newborn lymphocytes and of multiple extra-embryonic tissues was indicative of confined placental mosaicism. The second case was also associated with a normal pregnancy outcome and postnatal development, and only euploid cells were found in peripheral blood after birth. However, maternal isodisomy 17 consequent to a meiosis II error and loss of a chromosome 17 homologue was detected in peripheral lymphocytes postnatally. In the third case, pathological examination after termination of pregnancy showed growth retardation and minor dysmorphisms, and the trisomic line was detected in foetal skin fibroblasts. In addition, biparental derivation of chromosome 17 was demonstrated in the euploid lineage. These results, together with previously reported data, indicate that true amniotic trisomy 17 mosaicism is more commonly of extra-embryonic origin and associated with normal foetal development. Phenotypic consequences may arise when the trisomic line is present in foetal tissues. Case 2 also represents the first observation of maternal UPD involving chromosome 17; the absence of phenotypic anomalies in the child suggests that chromosome 17 is not likely to be subject to imprinting in maternal gametes. ( info) |