A MOLECULARLY CHARACTERIZED INTERSTITIAL DELETION ENCOMPASSING THE 11q14.1-q23.3 REGION IN A CASE WITH MULTIPLE CONGENITAL ABNORMALITIES

Interstitial deletion of chromosome 11 long arm is a rare event. In most of the interstitial deletions on the long arm of chromosome 11 both the position and the size of these deletions are heterogeneous making a precise karyotype-phenotype correlation. In only a few of the reported cases has the deletion been molecularly characterized. Our patient was a 13-year-old male presented; mental motor retardation, strabismus, myopia, retinopathy, sensorineural hearing loss, a long and triangular face, a broad forehead, hypotelorism, nasal septal deviation, a beaked nose, hypoplastic ala nasie, bilateral low-set ears, a high arched palate, crowded teeth, retrognathia, thin lips, a long neck, and sloping shoulders, hyperactive behavior, pulmonary stenosis and lumbar scoliosis. Conventional cytogenetic analysis revealed 46,XY,del(11)(q14.1-q23.3) karyotype in the patient. Array-CGH analysis of the patient's DNA revealed an interstitial deletion encompassing 33.2 Mb in the 11q14.1-q23.3 genomic region (chr11: 83,161,443-116,401,751 ; Hg19). In this report, we present a patient with an interstitial deletion on the long arm of chromosome 11 that encompassed the 11q14.1-q23.3 region; and, using array-CGH analysis, we molecularly characterized the deleted region.

PRENATAL DIAGNOSIS OF DE NOVO PERICENTRIC INVERSION INV(2)(p11.2z13)

We here report a prenatal case with de novo pericentric inversion inv(2)(p11.2q13). A 20-years-old G1PO woman was referred for amniocentesis at 17 weeks of gestation, because of a positive second trimester screening test for aneuploidy. A de novo pericentric inversion inv(2)(p11.2q13) was detected during conventional cytogenetic analysis. Array-CGH analysis of the fetus showed no subtle chromosomal imbalances at the breakpoints. Genetic counseling was given to the family and the family decided to continue the pregnancy. To our knowledge, our case is the third prenatally detected de novo case with inv(2)(p11.2q13), and also the first case in which molecular karyotyping analysis were also applied.

PRENATAL DIAGNOSIS OF DE NOVO SUPERNUMERARY MARKER CHROMOSOME ORIGINATED FROM CHROMOSOME 16 BY ARRAY-CGH

A 33 years-old pregnant woman was referred for amniocentesis at 19 weeks of gestation due to abnormal serum biochemistry. A non-satellited, monocentric marker chromosome was observed with a frequency of 50% in cultured amniocytes. Parental karyotypes were normal. The marker chromosome was found to be derived from chromosome 16 by FISH and array-CGH analysis. Genetic counseling was given to parents and the family decided to terminate the pregnancy. Dysmorphic findings including; low set ears, exophtalmos depressed nasal bridge, large mouth and lips, posture anomalies at the extremities were detected at autopsy.

Prenatal management, pregnancy and pediatric outcomes in fetuses with septated cystic hygroma

It has been reported that, compared with simple increased nuchal translucency, fetal cases with septated cystic hygroma (CH) are more likely to face perinatal handicaps. However, pediatric outcomes and proper prenatal counseling for this anomaly have not yet been truly defined. We performed this study to determine pregnancy and pediatric outcomes of fetuses with septated CH. We searched records for cases with septated CH and collected data for structural abnormalities, karyotype analysis, and pregnancy outcomes. Fetuses born with septated CH were also evaluated for their pediatric outcomes. Sixty-nine fetuses with septated CH were enrolled in the study. Results showed that chromosomal abnormalities were present in 28 fetuses (40.6%), and the most common aneuploidy was Turner syndrome (n=14, 20.3%); 16 (23.2%) of the remaining cases, in which aneuploidy was not found, had coexistent structural malformations; 25 (36.2%) cases had normal karyotype and morphology. The total number of live births and infants with unfavorable neurologic follow-up were 13 (18.8%) and 2 (2.9%), respectively. Septated CH is associated with poor perinatal outcomes; therefore, karyotype analysis and ultrasonographic anomaly screening should be performed as initial steps, and expectant management should be offered to couples with euploid fetuses that have normal morphology.

Prenatal diagnosis of isochromosome 21p and isochromosome 21q in a fetus with Down syndrome

The aim of this study was to present the first case with Down syndrome in conjunction with de novo isochromosomes of both short and long arm of the chromosome 21. Cytogenetics, molecular cytogenetics and molecular genetic analysis were performed on chorionic villus sampling at 12 weeks of gestation of a 42-years-old pregnant woman. According to cytogenetics, molecular cytogenetics and molecular genetic analysis the karyotype was designated as: 47,XY,i(21) (qter --> q10::q10 --> qter),+i(21) (pter --> p10::p10 --> 10pter).ish i(21)(qter --> q10::q10 --> qter)(CEP13/21+,WCP21+),+i(21) (pter --> p10::p10 --> pter)(CEP13/21+,WCP21+). Quantitative Fluorescent Polymerase Chain Reaction (QF-PCR) analysis revealed that isochromosome 21q was maternal in origin. After the detailed genetic counseling, the family decided termination of the pregnancy. This is the first report of co-existence of an isochromosome 21p and an isochromosome 21q in a case with Down syndrome. Our case shows the importance of the molecular cytogenetics and molecular genetic analysis in cases with isochromosomes of the acrocentric chromosomes and supernumerary marker chromosomes regarding to highlight of the formation mechanisms of co-existence of these two rearrangements.

De novo supernumerary marker chromosome originating from chromosome 17 resulting in a normal pregnancy outcome

We report here a prenatal case with de novo supernumerary marker chromosome originating from chromosome 17 in non-mosaic form resulting in normal pregnancy outcome. In this case, a 26-year-old pregnant woman was referred for amniocenthesis and microdeletion Fluorescence In Situ Hybridization (FISH) testing at 18 weeks of gestation due to history of a previous child with Angelman Syndrome. PWS/AS region deletion was excluded by FISH. A de novo supernumerary, non-satellited, monocentric marker chromosome was detected during conventional cytogenetic analysis. With the use of FISH testing, it was found that the marker chromosome originated from chromosome 17. Additionally, the marker chromosome was found not to contain the Smith-Magenis and Miller Dieker syndrome regions. After detailed review of the literature, genetic counseling was given to the family, and the family decided to continue the pregnancy to term. A female child was born at term without any phenotypical abnormalities and clinical complications. Follow-up at 15 months-of-age revealed no developmental abnormalities. To our knowledge, our patient is the first reported prenatal case with a de novo monocentric, supernumerary marker chromosome derived from chromosome 17 in a non-mosaic form that resulting in normal pregnancy outcome.

Prenatal diagnosis of a de novo supernumerary marker chromosome originating from chromosome 16

Prenatal diagnosis of a de novo supernumerary marker chromosome originating from chromosome 16: A 37 year old pregnant woman was referred for amniocentesis at 18 weeks of gestation due to advanced maternal age and abnormal serum biochemistry. A nonsatellited, monocentric marker chromosome was observed with a frequency of 57% in cultured amniocytes. Parental karyotypes were normal. The marker chromosome was found to be derived from chromosome 16 by FISH using CEP16 and WCP16 probes. Marker chromosomes were not painted with M-FISH probe mixture, indicating an exclusively heterochromatin nature. CGH analysis using genomic DNA isolated from uncultured amniocytes also supported the M-FISH results. Genetic counseling was given to parents and the family decided to continue the pregnancy to term. The baby was born at 36 weeks of gestation without any dysmorphic features. Follow-up at 7 months of age revealed no developmental abnormalities.

Role of magnetic resonance imaging in the early diagnosis of Takayasu arteritis

Takayasu arteritis is a non-specific inflammatory process of unknown aetiology affecting the aorta and its major branches. It may lead to stenosis or occlusion. We have examined eight patients with clinically diagnosed Takayasu arteritis using contrast-enhanced MRI and also 3-D MR angiography. All patients were female and their ages varied between 22 and 48 years. We were able to show subtle arteritic changes and stenotic lesions in branch vessels in the early phase of the disease by using this imaging modality. Thus, we can state that contrast-enhanced MRI with 3-D MR angiography can be used for the initial diagnosis of Takayasu arteritis. It provides a means to evaluate the vascular tree non-invasively and may replace conventional angiography.

Novel cytogenetic findings revealed by conventional cytogenetic and FISH analyses in leukaemia patients

AIM

To describe novel cytogenetic findings in four leukaemia patients.

METHODS

Conventional cytogenetic (CC) and fluorescence in situ hybridization (FISH) analyses were performed on bone marrow samples of four leukaemia patients.

RESULTS

In this study, t(3;10)(q11;q25) and t(2;22)(p21;q11.2) were detected as novel translocations. t(8;16;21)(q22.1;q13;q22) and t(1;6;9;22)(p36.1;p21.3;q34;q11) were found as variant translocations, and these variant translocations were confirmed by Interphase-FISH and Multi-colour-FISH.

CONCLUSION

Newly identified cytogenetic findings can lead us to characterize cytogenetic evolution of the haematological malignancies. Further investigations are certainly warranted to resolve the prognostic impact of these new cytogenetic abnormalities.

M-FISH applications in clinical genetics

Until recently, presence of de novo marker or derivative chromosomes was quite problematic for genetic counseling especially in prenatal diagnosis, because characterization of marker and derivative chromosomes by conventional cytogenetic techniques was nearly impossible. However, recently developed molecular cytogenetic technique named Multicolor Fluorescence in Situ Hybridization (M-FISH) which paints all human chromosomes in 24 different colors allows us to characterize marker and derivative chromosomes in a single hybridization. In this study, we applied M-FISH to determine the origin of 3 marker and 3 derivative chromosomes. Marker chromosomes were found to originate from chromosome 15 in two postnatal and one prenatal case. Of these, one of the postnatal cases displayed clinical findings of inv dup (115) syndrome and the other of infertility, and the prenatal case went through amniocentesis due to the triple test results. Karyotypes of the patients with derivative chromosomes were designated as 46,XY,der (21)t(1;21)(q32;p11), 46,XX,der(8)t(8;9)(p23;p22) and 46,XX,der(18)t(18;20)(q32;p11.2) according to cytogenetic and M-FISH studies. All of the M-FISH results were confirmed with locus specific or whole chromosome painting probes. The case with der (8)t(8;9) had trisomy 9(p22-pter) and monosomy 8(p23-pter) due to this derivative chromosome. The case with der(18)t(18;20) had trisomy 20(p11.2-pter) and monosomy 18(q32-qter). Parental origins of the derivative chromosomes were analyzed using microsatellite markers located in the trisomic chromosomal segments. Patients' clinical findings were compared with the literature.

Telomere-specific fluorescence in situ hybridization analysis of couples with five or more recurrent miscarriages

Fluorescence in situ hybridization analysis using telomere specific probes has been used to detect cryptic translocations in the chromosomal telomeric regions. This study was performed in five clinically normal couples who have had five or more spontaneous abortions and whose karyotypes were found to be normal using conventional cytogenetic techniques. Using the telomere specific probes, in one couple we determined a cryptic translocation between chromosome 3 and 10, and, in another couple, the signal in chromosome 20 was detected in another chromosome, which was probably a D group chromosome. Additionally, in the latter and also in two other couples, we observed a polymorphism. The approach will be helpful for screening cryptic translocations using telomere specific multiple probe sets in couples with recurrent miscarriages. As prenatal diagnosis will be available for these couples for future pregnancies, it will be possible to help these families to have healthy fetuses.