High-resolution Chromosome Analysis Research Articles

Prader‐Willi syndrome and Robertsonian translocations involving chromosome 15

A case of Prader-Willi syndrome is presented in which high resolution chromosome analysis revealed not only a familial Robertsonian translocation [t(13q15q)], but also a del(15) (q11.2q13) of the chromosome 15 not involved in the translocation. While there have been numerous reports of Robertsonian translocations involving chromosome 15 in patients with Prader-Willi syndrome, in this case, the Robertsonian translocation was shown to be unrelated to the clinical findings.

Short arm deletion of chromosome 1: del(1)(p13.3 p22.3) in a female infant with an extreme tetralogy of Fallot

High-resolution chromosome analysis showed the karyotype 46,XX,del(1)(p13.3 p22.3) in a female infant with an extreme tetralogy of Fallot and multiple congenital anomalies. The patient showed characteristic features: upper and lower eyelids connected to each other by a string-like epithelium, low hairline, epicanthal folds, saddle nose with a broad, flat root, micrognathia, short neck, high-arched palate, prominent xiphisternum, wide-spaced nipples, bilateral pes equinovarus, fifth toes that overlapped the fourth toes bilaterally, a deep fissure between the first and second toes bilaterally, and abnormal flexions of fingers and toes. Growth and psychomotor retardation were also noted. Cardiac catheterization revealed an extreme tetralogy of Fallot complicated by a patent ductus arteriosus. Ventricular tachycardia and ventricular premature beats developed during the neonatal period and did not respond well to anti-arrhythmic drugs. She died of the anoxia caused by closure of the patent ductus arteriosus when she was 7 months old.

Monosomy for 21pter-q21: Case report and assignment of a DNA clone (Fr8-77) to the deleted segment

A 4-month-old Japanese girl with partial monosomy 21 was described. The patient has craniofacial anomalies, a short neck, wide-set nipples, anal atresia, deformed feet, hypertonia, intrauterine growth retardation, and mental deficiency. RFA- and high-resolution GTG-banding chromosome analyses, and Southern- and slot-blot analyses interpreted her karyotype as 45,XX,-2,-21, + der(2)t(2:21)(q37.3;q22.1). The origin of this de novo translocation ascertained by analyses with both QFQ-heteromorphisms and a Fr8-77/BamHI RFLP was paternal. Comparison of the patient with previously reported patients confirmed that her manifestations are consistent with those of monosomy for 21pter-q21. Based on the results of molecular analyses on the present patient, a DNA clone, Fr8-77 (D21S82), was assigned to pter-q21.

Chromosome evolution and high‐resolution analysis of leucocytes, bone marrow, and tumor cells of retinoblastoma patients

High-resolution cytogenetics were applied to leucocytes, bone marrow, and tumors of 8 retinoblastoma (Rb) patients in search of microdeletions or subtle rearrangements and in order to determine clonal evolution. Four of 9 tumors (Rb1, Rb6.1, Rb6.2, and Rb8) showed a deletion in the characteristic region on 13q while 2 others (Rb3 and Rb4) were hemizygous for chromosome 13 in approximately one-third of the cells. Our study presents a particularly high incidence of chromosome 13 anomalies as compared to the previously published data. Furthermore, comparison of karyotypes of 3 significant cases (Rb1, Rb6, and Rb8) allows the reconstruction of the necessary steps in the evolution of retinoblastoma. It also shows the need for a double mutation in tumor development, both in hereditary and non-hereditary cases. High-resolution chromosome analysis of retinoblastoma patients provides a rare opportunity to study the succession of events necessary for tumor development.

Localization on pig chromosome 6 of markers GPI, APOE, and ENO1, carried by human chromosomes 1 and 19, using in situ hybridization

In the pig, the linkage group around the halothane gene (HAL), composed of S-GPI-HAL-H-A1BG-PGD, has been assigned to bands p1.2----q2.2 of chromosome 6. In man, ENO1-PGD and APOE-GPI constitute two syntenic groups situated on different chromosomes (1 and 19, respectively). Since GPI and PGD are linked in the pig, we have hybridized the human cDNA probes for ENO1 and APOE to pig chromosomes. These markers were assigned to pig chromosome 6, in the q2.2----q2.4 and cen----q2.1 regions, respectively, using in situ hybridization. Since GPI and APOE are situated in the same region, we combined the use of high resolution chromosome analysis and in situ hybridization to give a more precise localization in the q1.2 and q1.2----q2.1.2 regions of chromosome 6. A possible linear order of these genes is proposed.

A de novo X; 3 translocation in Rett syndrome

Rett syndrome is a neurodegenerative disorder that occurs exclusively in females. The syndrome is sporadic in most cases with the exception of a few familial cases with an inheritance pattern through maternal lines. These observations raised the possibility that Rett syndrome may be due to an X-linked dominant mutation which is lethal in the male. To evaluate this hypothesis, we have systematically performed high-resolution chromosome analysis on 28 patients with Rett syndrome searching for deletions and/or translocations. In one patient, a de novo balanced translocation was observed with the chromosome constitution of 46,X,t(X;3) (p22.11;q13.31). This finding supports the hypothesis of an X-linked dominant mutation and suggests that the Rett gene might map to distal Xp21 or proximal Xp22.

Chromosome deletion of Xq25 in an individual with X-linked lymphoproliferative disease.

High resolution chromosome analysis was done on lymphoblastoid cell lines, established during the past decade from affected males with X-linked lymphoproliferative disease (XLP) or from obligate female carriers, from 14 families. One cell line, from a male with XLP, has a partial deletion of band Xq25. The constitutional nature of the deletion is confirmed in chromosome studies of peripheral blood from the affected individual and represents the first such structural defect to be described in this disorder. Cell lines from the remaining 13 families do not have cytogenetically detectable deletions. This observation will facilitate precise localization, cloning and sequencing of the gene causing XLP.

Phylogenetic Relationships of the Sorex araneus–arcticus Species Complex (Insectivora, Soricidae) Based on High-Resolution Chromosome Analysis

High-resolution chromosome analysis of four species of the Sorex araneus–arcticus complex (Insectivora, Soricidae), namely S. granarius, S. araneus, S. coronatus, and S. arcticus, revealed that their karyotypes are composed of the same original chromosome material that may have been present in chromosomes of S. granarius. The karyotypes of the other three species could have been derived from that of S. granarius by means of three types of chromosomal rearrangements: Robertsonian translocations, telomere–centromere translocations, and centromeric shifts. These types of rearrangements imply that the direction of chromosomal evolution in these species has been from high to low chromosome numbers. It is supposed that this reconstructed scheme of chromosomal evolution reflects the phylogenetic relationships among the species of the araneus–arcticus complex that were studied.

Fragile sites at 4q23 and 7q11.23 unique to bone marrow cells

Fragile sites in chromosome bands 4q23 and 7q11.23 were discovered in bone marrow cells. Expression of these fragile sites was induced by treatment of the cells sequentially with 10 −7 M methotrexate and then 10 −5 M thymidine. No expression was observed in bone marrow cells without treatment. The fragile sites at 4q23 and 7q11.23 were seen individually, together, and in the homozygous state in a total of 20 bone marrow samples. The bone marrow karyotypes were normal in all cases. Expression of these common fragile sites at 4q23 and 7q11.23 could not be induced in blood lymphocytes from two subjects using methotrexate and thymidine, or by other means including the addition of bromodeoxyuridine and fluorodeoxyuridine or growth in folate-deficient medium. Because the fragile sites at 4q23 and 7q11.23 have never been observed in lymphocytes treated with methotrexate and thymidine for high-resolution chromosome analysis, it appears that these fragile sites are not expressed under these conditions in T lymphocytes. We propose that the differential expression of these fragile sites in bone marrow cells reflects genes active in bone marrow cells but not in blood lymphocytes.

Sequential G- to R-banding for high resolution chromosome analysis

A sequential staining protocol for revealing first G- and then R-bands on early metaphase chromosomes is presented. Lymphocyte cultures are synchronized with methotrexate, and released from the S-phase block with bromodeoxyuridine. The resulting early metaphase cells are initially G-banded with Wright's stain and then R-banded by the fluorescence plus Giemsa (FPG) technique.

Interstitial deletion 1p in a 30 year old woman.

High resolution chromosome analysis showed the karyotype 46,XX,del(1)(p22.1 p31.2) in a 30 year old woman with psychomotor retardation and various malformations. Determination of the enzyme phosphoglucomutase 1 (PGM1) showed that she was a heterozygote. Three other cases of interstitial deletion 1p have been reported previously, and one of these cases had several features in common with our case, suggesting a distinct syndrome.

High resolution chromosome and DNA analysis in multiple endocrine neoplasia type II syndrome.

Multiple endocrine neoplasia type II (MEN-II or Sipple's syndrome) is an autosomal dominant disorder characterized by medullary thyroid cancers, pheochromocytomas, and parathyroid adenomas. A blind analysis of high resolution G-banded chromosomes was performed on blood specimens from eight MEN-II individuals from three unrelated families and six control subjects. Seven of eight MEN-II patients and one of six control subjects were determined to have a deletion at 20p12.2. These findings support the hypothesis that MEN-II patients have a 20p12.2 deletion (chi 2 = 6.99; p less than 0.01). Genomic DNA from seven of the eight MEN-II patients was studied using the DNA probe, D20S5, localized by in situ hybridization to 20p12. The probe binding site is not deleted in some MEN-II patients, as demonstrated by the presence of two alleles detected as restriction fragment length polymorphisms. Thus, D20S5 does not hybridize to DNA sequences that are deleted based on cytogenetic analysis in MEN-II patients.

Constitutional interstitial deletion of 11p11 and pericentric inversion of chromosome 9 in a patient with Wiedemann-Beckwith syndrome and hepatoblastoma

A constitutional interstitial deletion on the short arm of chromosome #11 and an inversion of the heterochromatin of chromosome #9 were detected in'a 1.5-year-old boy with Wiedemann-Beckwith syndrome (WBS) and hepatoblastoma. Of 37 malignant and nine benign neoplasms reported in approximately 250 cases with complete and incomplete forms of WBS, this is the fourth patient with hepatoblastoma. To date, 28 cases of WBS have been cytogenetically investigated with banding techniques. Constitutional anomalies have been found in only nine cases: Various anomalies resulting in a common triplication of the 11p15 region in six cases, reciprocal translocations t(11;22) and t(X;1) and an inversion of chromosome #2 in the three remaining cases. Triplication 11p15 was only present in one of four cases with a tumor. The breakpoints of the unique del(11)(p11.1p11.2) present in our case are proximal to those of del(11p13–11p14) and dup(11p15) observed thus far in both the aniridia-Wilms' tumor association and in WBS. Inversion of chromosome #9—one of the heterochromatin variants associated with elevated chromosomal instability, increased congenital abnormalities, and cancer proneness—may have been causally connected with a genetic imbalance resulting in the de novo deletion of 11p11. Therefore, we suggest that in these high-risk groups, C-banding studies should be performed together with high resolution chromosome analysis in order to also reveal the incidence and significance of C-band variants in individuals with such cancer prone syndromes.

Karyotype and ultrastructure of a colony stimulating factor (CSF) producing cell line (5637) originated from a carcinoma of the human urinary bladder.

The cell line 5637 which originated from a human urinary bladder carcinoma is known to produce GM-CSF and Multi-CSF ectopically. Determination of cell surface antigens defined by monoclonal antibodies was recently reported. Here we report on the ultrastructure and karyology of this CSF secreting cell line. At the ultrastructural level the monolayer in vitro culture and the solid tumors formed in nude mice showed all characteristics consistent with a well-differentiated transitional cell carcinoma (TCC). A subclone was found to grow in suspension and did not secrete any CSF activity. High resolution chromosome analysis revealed chromosomal abnormalities which agreed only in few particulars with nonrandom chromosomal aberrations usually found in TCC. Analysis of the cytogenetic results showed that nearly all structural abnormalities present are known to be associated with acute or chronic human leukemia. The possibility that the ectopic production of CSF in this cell line may be correlated to one or more of the described chromosomal aberrations is discussed.

Routine application of high resolution chromosome analysis.

Routine application of high resolution chromosome analysis.

High resolution chromosome analysis of constitutional and acquired t(15;17) maps c- erbA to Subband 17q11.2

High resolution chromosome analysis was performed on bone marrow cells from four patients with acute promyelocytic leukemia and t(15;17), and in lymphocytes from two unrelated, phenotypically normal persons with an apparently identical constitutional translocation. Scrutiny of prophase-prometaphase chromosomes localized the breakpoints in all six cases to subbands 15q22.3 and 17q11.2. Molecular genetic studies have localized the oncogene c- erbA to chromosome #17 between the breakpoints of the constitutional and the acquired anomaly. The present results, therefore, map c- erbA to subband 17q11.2.

High resolution cytogenetic evaluation of couples with recurring fetal wastage.

Both high resolution and routine chromosome analyses were used to study couples with a history of two or more spontaneous abortions in early pregnancy. In the 20 couples studied, two of the women were found to have an inversion. One paracentric inversion, (13)(q13.1q22.3), was apparent on routine analysis. The small pericentric inversion (11)(p11.12q12.3), was only detected by high resolution techniques. Given the low yield and increased cost and effort involved, we do not believe that high resolution studies are justified for screening couples with repeated abortions.

High-resolution chromosomal localization of the beta-gene of the human beta-globin gene complex by in situ hybridization.

A 4.4-kb PstI fragment containing the entire beta-gene of the human beta-globin gene cluster plus both 5'- and 3'-flanking sequences was used as a probe to study the chromosomal localization of the beta-gene by in situ hybridization. Using random oligonucleotides as primers, the beta-gene DNA was 3H-labeled with the large fragment of DNA polymerase I (Klenow fragment) to a specific activity of 1.2 X 10(8) cpm/micrograms. Almost 80% of hybridization grains observed were located on the distal short arm of chromosome 11. High-resolution chromosome analysis suggests a more precise location of the beta-gene to region 11p15.4----p15.5.

High-Resolution Chromosomes as an Independent Prognostic Indicator in Adult Acute Nonlymphocytic Leukemia

Using high-resolution chromosomes of bone-marrow specimens from 105 consecutive adult patients with de novo acute nonlymphocytic leukemia, we found an unusually high degree of complexity in this disorder, which may explain previous difficulties in identifying useful prognostic indicators. Specimens from 99 of the 105 patients were successfully analyzed, and 92 (93 per cent) had a chromosomal defect. Seventeen categories were identified, 12 representing a specific recurrent defect. Three of them have been found to have independent prognostic importance. Patients with an inversion 16 (9 per cent), diagnosed as having M2, M4, or M5b disease according to the morphologic classification of the French-American-British Acute Leukemia Cooperative Study Group, had a uniform and sustained complete remission and a median survival of 25 months. In contrast, 14 patients (14 per cent) with complex chromosomal abnormalities and a diagnosis of M1, M2, M4, M5a, or M6 disease had a very poor prognosis. In 12 of the 14 patients efforts to achieve induction of remission failed, and the group had a median survival of 2.5 months. A third group with a trisomy 8 as the single defect (11 per cent) had an intermediate prognosis and a median survival of 10 months. With the different types of treatment for acute nonlymphocytic leukemia that are now available, we suggest that high-resolution chromosome analysis will become an important tool in selecting specific types of therapy for groups of patients with differing prognoses.

The Prader-Willi syndrome and interstitial deletion of chromosome 15: high-resolution chromosome analyses of 14 patients with the Prader-Willi syndrome and of 5 suspected infants.

Fourteen patients with the Prader-Willi syndrome and five suspected infants were studied cytogenetically. High-resolution chromosome analyses with a modified ethidium bromide technique revealed an interstitial deletion of the proximal 15q in 13 out of the 14 typical patients and in four of the five suspected infants. A 15;15 Robertsonian translocation with a deletion in the proximal 15q was noticed in one infant. But in one patient, a normal karyotype was confirmed. The affected region common to all the patients was confined to a sub-band 15q11.2 (ISCN, 1981). These findings support the result of a recent study by Ledbetteret al. (1981, 1982), and indicate that the frequency of the 15q deletion in definite patients with the Prader-Willi syndrome is very high.