Displaced and tandem duplications in the long arm of chromosome 10 in maize

Lc, an anthocyanin pigmenting factor mapping somewhat more than one unit distal to R, is borne on a chromosomal segment which is homologous with part of the R-r:standard duplicated segment. Deficiencies and tandem duplications of the R to Lc region arise from exchanges within these obliquely paired homologous segments. The deficiencies are transmitted with a high, although reduced, frequency by the male gametophyte and are homozygous viable. Yet, the R to Lc region is not duplicated either proximal to R or distal to Lc. Thus the Lc-marked segment and either the P- or the S-marked segment of R-r constitute a displaced duplication. Such an arrangement can initiate a tandem and displaced duplication cycle.———No evidence was obtained for fractionation of the compound phenotype conditioned by Lc.     

Allelotyping of follicular thyroid tumors

To elucidate further the genetic mechanisms for follicular thyroid tumor development and progression, we allelotyped follicular thyroid tumors and other thyroid lesions from 92 patients. In general, a low frequency of loss of heterozygosity (LOH) was found, the highest being for chromosomes 3q, 10q, 11p, 11q, 13q, and 22q (10%–15%). However, detailed study of LOH of these chromosome arms with regard to the different histopathological diagnoses indicates that a locus on chromosome 10q may be involved in follicular thyroid tumor progression. In addition, the majority of Hürthle cell adenomas showed LOH on either chromosome 3q or 18q, in contrast to the other tumor types. This discrepancy in genetic alterations may contribute to the divergent clinical features occurring in these tumors.     

Fragile site long arm chromosome 16

Summary A fragile site at the long arms (q21) of chromosome 16 was found in two persons, each of whom became the parent of a child with a de novo structural chromosome abnormality—a balanced autosomal translocation and an autosomal deletion. The question of an increased risk of structural chromosome abnormalities in the offspring of persons with fragile site long arm 16 is discussed.     

Interstitial deletion in the long arm of chromosome 7

An interstitial deletion of 7q (q31.2-q32.3) is reported. Main features of this boy included facial dysmorphy, psychomotor retardation and absence of language.     

Reciprocal translocation between Y chromosome long arm euchromatin and the short arm of chromosome 1

A case with an apparently balanced reciprocal translocation between the long arm of the Y chromosome and the short arm of chromosome 1 t(Y;1)(q11.2;p34.3) is described. The translocation was found in a phenotypically normal male ascertained by infertility and presenting for intra-cytoplasmatic sperm injection treatment. Histological examination of testicular biopsies revealed spermatogenic failure. Chromosome painting with probes for chromosome 1 and for the euchromatic part of the Y chromsome confirmed the translocation of euchromatic Y chromosomal material onto the short arm of chromosome 1 and of a substantial part of the short arm of chromosome 1 onto the Y chromosome. Among the Y/autosome translocations, the rearrangements involving long arm euchromatin of the Y chromosome are relatively rare and mostly associated with infertility. Microdeletion screening at the azoospermia locus revealed no deletions, suggesting another mechanism causing infertility in this translocation carrier.     

Interstitial deletion of the long arm of chromosome 7

Summary Chromosome studies were carried out in a girl because of psychomotor retardation and difficulty in swallowing. The girl was admitted to hospital for the first time when 25 months old. The most characteristic signs revealed by the physical examination were short distal ulnar phalanges, clitoral hypertrophy, and very thin outer ear cartilages.An interstitial deletion of the long arm of chromosome 7 was observed: 7q22::7q31.Laboratory investigations revealed a remarkably high level of IgG, immunoglobulin, and an elevated value of serum FSH. No evidence of gene loci located at the deleted part of chromosome 7 were found.     

Interstitial delection of the long arm of chromosome 8

Summary This report describes a polymalformed 18-month-old male with an interstitial deletion of the long arm of chromosome 8. His karyotype is: 46,XY,del(8)(q21).     

Partial deletion of the long arm of chromosome 18

Summary A female infant with mental retardation and multiple somatic anomalies is described. The karyological analysis disclosed the partial deletion of the long arm of chromosome 18 in cells of probands peripheral blood culture. Repeated investigations of probands mothers peripheral blood cultures disclosed the presence of various chromosomal aberrations in 25–70% of cells.     

Interstitial deletion of the long arm of chromosome 3

A patient with multiple congenital malformations and developmental delay is reported. Her karyotype is 46,XX,del(3)(q23q25).     

Interstitial deletion of the long arm of chromosome 11

A female patient with an interstitial deletion of the long arm of chromosome 11 is described. Her growth and psychomotor development were normal. She showed some facial dysmorphic features including cleft lip/palate, a probable cardiac defect and a triphalangeal thumb. A clinical correlation with similar cases is presented.     

Interstitial deletion of long arm of chromosome 13

The case is presented of a patient with the karyotype 46,XX,del(13q)(pter----q22::q32----qter) confirmed by densitometry and a phenotype of mental and growth deficiency, hypotonia, hypertelorism, ptosis, broad nasal bridge, protruding upper incisors, short neck, dislocation of the hip, hypoplasia of the thumbs, fusion of fourth and fifth metacarpal bones and syndactyly of toes. The findings are compared with those of well documented cases with a similar deleted segment of the long arm of chromosome 13. Although it seems obvious that a clinical syndrome for the distal deletion 13q appears to exist more studies with banded chromosomes are needed.     

Isolation of a new polymorphic TC maize microsatellite located on the long arm of chromosome 10

Simple sequence repeats (SSR), also called microsatellites, were previously proved to be an important class of DNA markers. The isolation, mapping and designing of primers to the flanking regions of a new maize SSR is reported. The new marker, with a core motif of (TC) 12, designated as MZETC34, was mapped to the long arm of chromosome 10.     

Kinetics of DNA replication in a dicentric X chromosome formed by long arm to long arm fusion

Summary Utilizing the 5-bromo-deoxyuridine (BrdU) incorporation technique, we have recently studied the DNA replication kinetics in a dicentric X chromosome, formed by long arm-to-long arm fusion at band q23, from a 16-year-old black female with primary amenorrhea. The patient has a karyotype 45,X/46,X,dic(X)(q23).In the buccal smear the presence of X chromatin was found in 33% of the cells examined. The Barr bodies are large and 21% of them are bipartite. DNA replication studies were performed on the patient's lymphocytes by the thymidine pulse (T-pulse) method and confirmed comparatively by the BrdU pulse (B-pulse) method. The results indicate that the dicentric X chromosome is always late-replicating. The replication pattern is symmetric on both sides of the breakpoint and the replication sequence is, in order, p11, p22, q1(1–3), q22, q23, p21, and q21. This finding is comparable to those of other investigators and supports the theory that there exist two inactivation centers in the dicentric X chromosome, located on or near the q21 band.     

Langer-Giedion syndrome and deletion in the long arm of chromosome 8

Del(8) (q24.11-q24.13) were detected in 3 patients with typical Langer-Giedion syndrome (LGS) and studied by high-resolution methods. Analysis of the literature strongly suggests the chromosomal ethiology of the LGS, because in all patients examined in detail a deletion of the segment 8(q24.11-q24.13) was revealed, which is critical for the LGS. Interrelationships between the LGS and two monogenic conditions-tricho-rhino-phalangeal syndrome type I and multiple exostoses are discussed. The possible role of c-myc oncogene in exostoses' (including those in LGS) origin is anticipated.     

Allelotype of human thyroid tumors: loss of chromosome 11q13 sequences in follicular neoplasms.

Two classes of genes are the targets of mutations involved in human tumorigenesis: oncogenes, the activation of which leads to growth stimulation, and tumor suppressor genes, which become tumorigenic through loss of function, often through allelic deletion. To obtain evidence for a role for tumor suppressor genes in thyroid tumorigenesis, we examined DNA from 80 thyroid neoplasms for loss of heterozygosity in multiple chromosomal loci using 19 polymorphic genomic probes. None of the informative thyroid tumors studied had allelic loss detected with probes for chromosome 2q (D2S44), 3p (D3F15S2, D3S32), 3q (D3S46), 4p (D4S125), 6p (D6S40), 8q (D8S39), 9q (D9S7), 12p (D12S14), 13q (D13S52), 17p (D17S30), or 18q (D18S10). One of eight of the follicular adenomas had a 10q deletion detected with marker D10S15, and one of 26 had a 10q deletion detected with D10S25. One of two of the follicular carcinomas had an 11p deletion in the H-ras locus. The most significant findings were on chromosome 11q13, the site containing the putative gene predisposing to multiple endocrine neoplasia type I. Four of 27 follicular adenomas had loss of heterozygosity for probes in this region. Allelic deletions were detected with the following probes: D11S149, PYGM, D11S146, and INT2. None of 13 informative papillary carcinomas and none of two follicular carcinomas had loss of heterozygosity detectable with these 11q13 markers. Allelic loss is a relatively infrequent event in human thyroid tumors. Deletions of chromosome 11q13 are present in about 14% of follicular, but not papillary, neoplasms.(ABSTRACT TRUNCATED AT 250 WORDS)     

A detailed genetic map of the long arm of chromosome 11

We describe 14 new restriction fragment length polymorphisms, corresponding to 13 loci on the long arm of chromosome 11. A detailed genetic map of chromosome 11q has been constructed from these and other loci (a total of 31 loci) typed in 59 reference families. The 23 most informative markers were selected to establish a map with a strongly supported order; regional localizations are provided for eight other markers. The loci span 88 cM in males and 148 cM in females and form a dense continuum on 11q. These ordered polymorphic markers will be of help in studying the genes responsible for several diseases that have been localized to this region, including genes responsible for multiple endocrine neoplasia type I (MEN1), ataxia telangiectasia (AT), tuberous sclerosis (TSC), and some forms of asthma and rhinitis.