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.

Ring chromosome 21 and monosomy 21 mosaicism in a patient with azoospermia.

In this report, we describe a patient with azoospermia in conjection with de novo ring chromosome 21 and monosomy 21 mosaicism. Inter-phase fluorescence in situ hybridisation (FISH) studies on uncultured peripheral blood and epithelial cells obtained by buccal smear revealed that 25% of the uncultured blood cells and 11% of the epithelial cells were monosomic for chromosome 21. Y chromosome microdeletion analysis ruled out the presence of any genomic deletions in the azoospermic factor a,b,c regions on the long arm of chromosome Y. Additionally, through subtelomeric FISH analysis, it was found that there was no deletion in the subtelomeric region of ring chromosome 21. Our results indicate that ring chromosome 21 is a rare, but recurrent chromosomal abnormality in male factor infertility. Furthermore, in individuals with ring chromosome 21, defective spermatogenesis is not associated with the deletion of any gene or genes located in the subtelomeric region of chromosome 21.

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.

Turner Syndrome with Isochromosome Xq and Familial Reciprocal Translocation t(4;16)(p15.2;p13.1).

We present here a 16-year-old Turner syndrome patient with a complex karyotype that includes a maternally-inherited balanced translocation between chromosomes 4 and 16 and mosaicism of the isochromosome Xq10. Her karyotype was 45,X,t(4;16) (p15.2;p13.1)[9]/46,X,i(X) (q10),t(4;16)(p15.2;p13.1) [91]. The karyotype of her father was normal, whereas that of her mother had the same balanced translocation and numerical abnormalities of chromosome X and was designated as 45,X,t(4;16)(p15.2;p13.1) [2]/46,XX,t(4;16)(p15.2;p13.1)[93]/47,XXX,t(4;16) (p15.2; p13.1)[5]. The two siblings of the patient also had the same reciprocal translocation. We consider this to be the first such patient with an inherited reciprocal translocation and structural abnormality of the X chromosome (isochromosome Xq).

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.

A case with de novo interstitial deletion of chromosome 7q21.1-q22.

A case with de novo interstitial deletion of chromosome 7q21.1-q22: A patient with multiple congenital anomalies was found to have a de novo proximal interstitial deletion of chromosome 7q21.1-q22. The patient was 10.5 years of age, and manifestations include growth retardation (below 3rd percentile), mental retardation, mild microcephaly, hypersensitivity to noise, mild spasticity, short palpebral fissures, alternant exotropia, compensated hypermetropic astigmatism, hypotelorism, hypoplastic labia majora and minora, clinodactyly of fingers 4 and 5. Molecular studies revealed that the deletion had a paternal origin, while chromosomes of both parents cytogenetically were shown to be normal. Molecular, and fluorescence in situ hybridization (FISH) analyses confirmed no deletion at the Williams-Beuren Syndrome region. Some of the heterogeneous clinical findings were consistent with previously reported cases of same chromosomal breakpoints.

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.

Cytogenetic findings in thirty lung carcinoma patients.

Primary tissue cultures of human lung tumors were prepared from 30 cases of which 16 were diagnosed as squamous cell carcinoma, six adenocarcinoma, four adenosquamous cell carcinoma, three large cell carcinoma, and one small cell lung carcinoma. Chromosomal abnormalities were observed in 26 cases by cytogenetic studies with a GTG banding technique. Specific chromosome bands frequently involved in structural abnormalities were seen on 1p11, 1q11, 2p10, 6p10, 7q11, 7q22, 7q32, 8q22, 9q22, 11q11, 21q10, and Xq24. We assumed that especially i(2)(p10), i(9)(p10), i(21)(q10), t(11;12), t(14;15), del(X)(q24), and loss of the Y chromosome may play a role in the development of lung cancer as secondary changes. In this way, our cytogenetic findings provide evidence that multiple genetic lesions are associated with the pathogenesis of lung cancer.