Detection of trisomy 12 by fluorescence in situ hybridization on archival cytopathologic material in chronic lymphocytic leukemia/small lymphocytic lymphoma

OBJECTIVE: To evaluate fluorescence in situ hybridization (FISH) for the detection of trisomy 12 in archival cytologic specimens of chronic lymphocytic leukemia/small lymphocytic lymphoma. STUDY DESIGN: The cytopathology database was searched for all cases of chronic lymphocytic leukemia/small lymphocytic lymphoma. Six cases of chronic lymphocytic leukemia/small lymphocytic lymphoma obtained by fine needle aspiration and one case of small lymphocytic lymphoma with plasmacytoid features were analyzed for trisomy 12 by FISH. These cases had been archived between 1 week to 16 months prior to analysis. RESULTS: We detected trisomy 12 in four of the six cases of small lymphocytic lymphoma/chronic lymphocytic leukemia. The case of small lymphocytic lymphoma with plasmacytoid features was negative for trisomy 12. CONCLUSION: Detection of trisomy 12 by FISH can be effectively performed on routinely prepared, stained and coverslipped archival cytologic material.     

Clinical and molecular cytogenetic studies in a case with partial trisomy 12p due to a de novo supernumerary ring chromosome

Clinical and molecular cytogenetic studies in a case with partial trisomy 12p due to a de novo supernumerary ring chromosome: We report on a girl with a mosaic karyotype containing a supernumerary ring chromosome. Fluorescence in situ hybridization (FISH) studies showed that this marker chromosome was derived from chromosome 12, resulting in partial trisomy 12p13.1-->12q11. The girl showed developmental delay, cerebral visual impairment, obesity and mild dysmorphic features. Her clinical data at 6 months, 3 years, and 6 years of age were compared with the clinical data on other trisomy 12p patients.     

Partial trisomy of chromosome 18 (pter----q12) following a familial 18;21 translocation rcp(18;21)(q12;q11)

A 1-year-old boy with trisomy 18 (pter----q12) following a paternal balanced translocation revealed microcephaly, a pattern of minor dysmorphic features including upslanting narrow palpebral fissures, receding forehead, large nose and receding mandible, cryptorchidism, flexion contractures of fingers, a cardiac malformation and moderate mental retardation. While pure trisomy 18p generally goes along with a near-normal phenotype, additional trisomy of only a short segment of the proximal long arm 18 has a distinct negative influence on the phenotype, as seen in our proband.     

Double translocation t(7;12),t(2;6) heterozygosity in one family

Summary Double translocation heterozygosity t(2;6),t(7;12) in three generations of a Dutch family is described: the segregation of a double translocation in more than one generation has not been previously published. The index case was a 16-year-old mentally retarded boy with partial trisomy 12p who showed several dysmorphic features such as high prominent forehead, flat face, flat and short nose bridge, short nose, dysplastic ears, prominent lower lip, and several skeletal abnormalities. Based on the findings in this patient and those in nine other cases, the existence of a specific trisomy 12p syndrome is postulated.     

Viability of trisomy 12 cells in mouse chimaeras

Summary Mouse aggregation chimaeras consisting of trisomy 12 and normal euploid cells were produced. The analysis of one trisomy 12euploid chimaera, using biochemical and cytological markers, showed that the trisomic cells were able to participate in the formation of most tissues including the ovary. On the other hand, no trisomy 12 cells were found in lymphocyte populations, which is most likely due to early selection in this particular cell lineage. The viability of two adult trisomy 12 chimaeras demonstrates that trisomy 12 cells are able to develop beyond the fetal stage which is not observed in completely trisomic fetuses.Furthermore, these chimaeras did not show any sign of a trisomy 12 syndrome, indicating that the trisomy 12 cells were functionally integrated and participated normally in the differentiation of the various tissues. Our results suggest that trisomy 12 in the mouse is not autonomously cell lethal but can be rescued and is perfectly viable in the presence of normal diploid cells.This article is dedicated to the memory of Prof. A. Gropp     

Two cases of trisomy 12p due to rcpt(12;21)(p11;p11) inherited through three generations

Summary Two cases of trisomy 12p due to a familial translocation t(12;21) (p11;p11) inherited through three generations are presented. The clinical features of both affected individuals are consistent with those previously reported. Study of the NORs by silver staining showed translocation of the NOR from chromosome 21 onto the der(12) and suggested that the activity of this site has been suppressed in some carriers.     

Trisomy 12p syndrome

Summary The first case of trisomy of probable 12p mosaicism originated de novo is presented. Comparison of the clinical findings of this patient with those of previously described cases of 12p trisomy derived from translocated chromosomes indicates that the symptoms of 12p trisomy are: (1) normal birth weight and physical development, (2) severe psychomotor retardation and generalized hypotonia, (3) peculiarly round face with prominent cheeks, hypertelorism, epicanthus, broad, flat nasal bridge, short nose with anteverted nostrils, large philtrum, broad, prominent lower lip, and (4) poly(syn)dactyly of feet.     

47,XY,+der(11;22)(q23;q12) following balanced translocation t(11;22)(q23;q12)mat

Summary Report of a supernumerary extra chromosome der(11;22)(q23; q12) resulting from a balanced translocation in the mother. The propositus suffers from mental deficiency, deafness and extreme muscular weakness and exhibits cleft palate, a labial lymphangioma and an atrial septum defect. Since the features of partial trisomy 11q23 frequently associated with a translocation t(11q;22q) bear similarities with the cases of so called trisomy 22 one might conjecture that some of these observations are in fact products of translocations including partial 11q.     

A case of trisomy 12 mosaicism with pituitary malformation and polycystic ovary syndrome

We report the case of a patient (followed from birth to 15 years) presenting with trisomy 12 mosaicism, and focus on the endocrine phenotype associating a pituitary malformation and ovarian abnormalities. We describe the dysmorphic features and their evolution, the growth retardation and ovarian symptoms. Complete growth hormone deficiency was confirmed on auxological data, stimulation test and was related to pituitary stalk interruption, diagnosed by magnetic resonance imaging. Effect of growth hormone treatment was satisfactory resulting in a normal adult height. She also presented premature thelarche associated with right ovarian hypertrophy (4 to 5 fold the volume of the left ovary) which remained constant until 15 years of age. Diagnosis of trisomy 12 mosaicism was made on skin and ovarian karyotypes. The possible relation between these endocine findings and some genes located on chromosome 12 involved in pituitary and ovarian development is discussed.     

12P trisomy: a syndrome?

A 2 2/3-year-old girl with 12p trisomy resulting from a maternal translocation is presented. Her clinical symptoms are strikingly similar to the other four cases known in the literature. A characteristic combination of symptoms for a 12p trisomy syndrome is delineated.     

Trisomy 12p due to an adjacent 1 segregation of a maternal reciprocal translocation t(12;18) (p11;q23).

A 5, 9-12-year-old with trisomy 12 pdue to a maternal reciprocal translocation adjacent 1 segregation is presented. Comparison of his phenotype with that of other patients reported in the literature confirm the existence of a trisomy syndrome.     

Pure partial trisomy 6p due to a familial insertion (16;6)(p12;p21.2p23)

There have only been eight patients with 6p pure trisomy involving different segments: four cases resulted from a translocation or insertion and four were due to an intrachromosomal duplication. We report here the first postnatally ascertained patient with a pure 6p partial trisomy due to an interchromosomal insertion (16;6)(p12;p21.2p23)mat. This rearrangement was confirmed by fluorescent in situ hybridization (FISH) with whole chromosome 6 and 16 painting probes. The clinical findings in the present patient were similar to those observed in previous cases, including craniofacial dysmorphism, minor anomalies, and lack of severe anatomical defects; yet, the unspecificity of many of these features prevented us from delineating the 6p pure trisomy syndrome.     

Partial trisomy 18q12, due to intrachromosomal duplication,is not associated with typical 18 trisomy phenotype

Summary Partial 18q12 trisomy, due to intrachromosomal duplication, was found in a severely mentally retarded boy. The finding of nonspecific dysmorphism in this patient demonstrates that trisomy of band 18q12 is accompanied by neither a full nor an incomplete 18 trisomy phenotype, indicating that this phenotype may be due solely to trisomy of the 18q11 band.     

Acrocallosal syndrome in a child with de novo inverted tandem duplication of 12p11.2-p13.3.

Report on the child of normal unrelated parents presenting the typical features of acrocallosal syndrome (craniofacial dysmorphy, mental deficiency, convulsive disorder, agenesis of corpus callosum, preaxial polydactyly "hallux duplex" of both feet, and in addition diabetes insipidus) in which a mirror duplication of nearly the entire short arm of chromosome 12 was discovered. Since the symptomatology of trisomy and tetrasomy 12p shows some overlap with acrocallosal syndrome a common origin of the monogenic disorder and the chromosomal phenotypes is discussed.     

Syndrome +12p

Summary Familial 12/15 translocation with a child trisomic for the short arm of chromosome 12 (segment p 12.1pter) is reported. The clinical picture of the child is strikingly similar to previous reports of 12p trisomy. The main symptoms of 12p syndrome are defined.     

A new partial trisomy 12p with artery catheter vagus, congenital cataracts, external auditory canal, and no turbinate

We describe the prenatal diagnosis and fetal phenotype of partial trisomy 12 (p12-pter) transmitted from a maternal reciprocal translocation 6;12. Genetic analysis was conducted on umbilical cord blood for a fetus accompanied with tricuspid regurgitation and orbital hypertelorism from a 27-year-old gravida 4, para 1 after sonography at gestation 35weeks. The karyotype was unusual, with 46, XY, der (6), t (6;12) (p24; p12) mat. The pregnancy was terminated at 37 gestational weeks. The aborted fetus displayed dysmorphic features of a round flat face with prominent cheeks and high forehead, hypertelorism, short nose, broad and depressed nasal bridge, anteverted nares, deformed philtrum, open mouth, thin upper vermilion and broad everted lower lip, low-set ears and aural atresia, broad hands with simian creases, and a short neck. Fetal anatomy showed right artery catheter vagus, congenital cataract, no turbinate and external auditory canals. Through karyotype-phenotype analysis of this patient and a review of other reported cases, we believe this is a first report that expands the database of partial trisomy 12p, and is beneficial for future clinical genetic counseling. This study supports that phenotypic variability depends on the type and extent of the associated partial monosomy.     

Trisomy 15q23----qter due to a de novo t(11;15)(q25;q23) and assignment of the critical segment

A 10 10/12-year-old boy with a de novo t(11;15)(q25;q23) leading to trisomy 15q23----qter was studied. The clinical features were compatible with other cases of distal trisomy 15q. The critical segment for this trisomy is tentatively assigned to bands 15q25----qter.     

46,XX,-12,+der(12),rcp(3;12)(p25.1;p13.31)pat karyotype in a girl. Probable subregional assignment of glyceraldehyde-3-phosphate dehydrogenase locus to 12p13.1----p13.31 by exclusion mapping

A female infant with partial trisomy 3p and a terminal deletion 12p, due to a paternal (3;12)(p25.1;p13.31) translocation is described. Normal glyceraldehyde-3-phosphate (GAPD) activity in the proposita tentatively excludes GAPD locus from the deleted segment. Therefore, the region for this locus is reduced to 12p13.1----p13.31.     

A case of de novo trisomy 12p syndrome

We described a case of complete trisomy 12p syndrome (non-mosaic) originating de novo in a first born child to healthy 26 year old nonconsanguineous parents. The 12p syndrome has been confirmed by clinical, cytogenetic and gene dosage studies.     

First trimester screening for trisomy 21 in gestational week 8-10 by ADAM12-S as a maternal serum marker

Background  

A disintegrin and metalloprotease 12 (ADAM12-S) has previously been reported to be significantly reduced in maternal serum from women with fetal aneuploidy early in the first trimester and to significantly improve the quality of risk assessment for fetal trisomy 21 in prenatal screening. The aim of this study was to determine whether ADAM12-S is a useful serum marker for fetal trisomy 21 using the mixture model.