X long-arm deletions. A review of non-mosaic cases studied with banding techniques

A woman with secondary amenorrhoea and an X long-arm deletion (pter----q21:) is described and compared with 30 adult non-mosaic, banded cases. Approximately 50% of the patients had gonadal dysgenesis associated with a higher frequency of short stature and "Turner stigmata" than in women with indication of ovarian activity. It is suggested that preservation of bands Xq26----28 may be decisive for normal ovarian function.

Sister chromatid exchange in patients treated with methotrexate for psoriasis

Sister chromatid exchange (SCE), which is considered a sensitive method in evaluation of mutagenicity and may be an indicator of carcinogenicity, was determined in lymphocytes from 8 patients with severe psoriasis who underwent treatment with oral methotrexate (MTX). During the treatment period (median 118 days, range 50-298 days) a significant increase in SCE compared to the pretreatment value was found in 1 patient only. It is concluded that no long-term damage as measured by SCE occurs in lymphocytes from psoriasis patients treated with MTX.

Distribution of SCEs in lymphocytes in persons with normal, slightly increased, and heavily increased SCEs

The distribution of SCEs in lymphocytes was examined for 165 healthy persons (58 non-smokers and 107 smokers with cigarette consumption ranging from 1 to greater than 20 per day), and for 1 patient treated with melphalan, a cytostatic drug. The data from the healthy persons did not follow a Poisson distribution. A mixed Poisson that allowed different lambda values for the 30 cells scored from each person and postulated a gamma distribution for the lambda s within the 30 cells fitted all the data examined including those from the melphalan-treated patient. In the latter case the 7 samples taken at various times after the treatment could all be represented satisfactorily with a common parameter, c, in the gamma distribution for the lambda s, even though the mean SCEs/cell varied from 9.8 to 36.8. Because the c parameter determines the spread of lambda values within the 30 cells, this suggested that the effect of the cytostatic drug was to increase all the lambda s by a constant amount. The sum of the SCEs taken over all 30 cells in a sample is a convenient summary statistic, and the transformation y = square root s + square root s + 1 behaves as a normal variate with a constant variance within a group.

Guidelines for the statistical evaluation of SCE

When planning studies by the sister chromatid exchange (SCE) test, it is necessary to calculate the size of the test groups, taking into consideration the variance of the test result and the statistical distribution of SCE frequencies. This paper deals with these problems. Recommendations are given for the preparation of slides under standardized conditions, for the subsequent counting of SCEs/cell in a random sample of 30 cells from each slide, and for the condensation of the information contained in the sample of 30 counts into a single statistic, that may be treated as a normally distributed variable. The adequacy of this transformation is shown for the data from 170 different subjects. Of these, 165 (58 nonsmokers and 107 cigarette smokers) had mean values of SCE/cell ranging from 6.5 to 13.5, while the remaining 5 subjects were on intermittent treatment with cytostatics every fourth wk, and exhibited a mean value of SCE/cell in the range 15-23. The variance associated with the recommended statistic has been decomposed into 4 variance components: variance within slides, variance between slides prepared from the same blood sample, variance within subjects, and variance between subjects. Based on a total of 680 SCE analyses in 218 persons, estimates of these variance components are given and used to calculate the necessary number of samples for the detection of a prescribed difference in SCEs/cell for selected values of Type I and Type II errors.

Chimeric twins. T.S. and M.R. reexamined

A pair of chimeric twins, T.S. (male) and M.R. (female), were examined. The amounts of 'foreign' blood cells in each twin found on three occasions were compared. The percentages of M.R. cells found in the blood of T.S. in 1977 and in 1982 were similar and about 1/5 of that found in 1970. The amount of T.S.-blood cells found in M.R. was declining slowly from about 31% in 1970 to about 25% in 1982.

Sister chromatid exchange in response to variations in occupational lead exposure

Sister chromatid exchange (SCE) rates in 10 long-term lead-exposed men increased significantly with increasing zinc protoporphyrin concentration in blood. SCE rates were also related to blood lead levels, but this correlation was not statistically significant. These results were obtained before the summer vacation. Six men were examined again shortly after the vacation; both SCE rates and lead-exposure parameters had decreased significantly. An increase was seen in one worker; however, this result could be related to a serious disease for which he was undergoing treatment. Continued examinations showed a tendency of increasing SCE rates and exposure parameters, but the follow-up was too incomplete to allow a statistical analysis. Further studies of 18 newly employed workers failed to show any increase in SCE during the first 4 months of employment despite some increases in both zinc protoporphyrin and lead levels in the blood. The results obtained suggest that a genotoxic effect due to inorganic lead may occur in long-term lead-exposed workers.

Lymphocyte function and chromosome aberrations in patients with early mycosis fungoides and parapsoriasis en plaques

Thirteen patients with stage I or II mycosis fungoides (MF) and 10 patients with large-plaque parapsoriasis en plaques (PEP) were examined for immunologic and cytogenetic disturbances. Total lymphocyte counts and immunoglobulin concentrations in the blood were normal. In vitro lymphocyte responses to polyclonal activators and various antigens in standard concentrations were normal. However, titration of phytohemagglutinin and concanavalin A (ConA) disclosed significantly lowered responses to suboptimal concentrations in the patient group, most pronounced in patients with MF II. ConA-induced leukocyte migration inhibitory factor (LIF) production, tested in an indirect leukocyte migration inhibitory assay, was low in the patient group. Furthermore spontaneous LIF production in vitro and small amounts of serum LIF were demonstrated in a few patients. The chromosomal banding pattern, sister chromatid exchange, and break frequency were within normal limits except for 3 translocations in the MF group. It is concluded that even in early-stage MF a pathologic function of blood lymphocytes can be demonstrated, when sensitive methods are applied. The findings might be important for monitoring disease activity and effect of treatment.

Interstitial deletion in the "critical region" of the long arm of the X chromosome in a mentally retarded boy and his normal mother

A family in which an intestitial deletion of the X chromosome, del(X)(q13q21.3), is segregating was ascertained through a boy with cleft lip and palate, agenesis of the corpus callosum, and severe mental retardation. The possible causal relationship to his chromosome abnormality is discussed. Although the deletion occurred within the critical region, the mother showed no signs of gonadal dysgenesis. A phenotypically normal daughter was, as her mother, monosomic for this region of the X, and both showed random inactivation of the X chromosome.

Sister chromatid exchanges and structural chromosome aberrations in lymphocytes in operating room personnel

Information on possible chromosomal damage in humans after long-term exposure to trace concentrations of waste anaesthetic gases is scarce. We examined peripheral lymphocytes in operating room personnel for both chromosome aberrations and sister chromatid exchanges (SCE). Following a standardized procedure of cultivation and staining, 30 cells from each person were scored for SCE and 100 cells from each person were examined for chromosome aberrations. A total of 45 persons were examined, representing anaesthetists (n = 15), operating room nurses assisting the surgeon (n = 10), nurses circulating in the operating room (n = 8) and healthy, unexposed controls (n = 12). The median duration of working in the operating room was 102 months, 66 months and 66 months, respectively. Time-weighted concentration levels of 2.5-4.3 p.p.m. of halothane and 25-400 p.p.m. of nitrous oxide were measured in the breathing zones of the anaesthetists during mask anaesthesia. Examination of SCE and chromosome aberrations yielded corresponding qualitative results. With both tests, no statistically significant difference was observed between the four groups of persons. It was concluded that by examination of both SCE and chromosome aberrations in peripheral lymphocytes in operating room personnel, no indication was found of a mutagenic effect of long-term exposure to trace concentrations of waste anaesthetic gases.

Normal sister-chromatid exchanges in oral contraceptive users

Sister-chromatid exchanges in peripheral lymphocytes were examined in 115 healthy women, aged 15-43 years. 63 women were on no medication at all, and 52 women used oral contraceptives. 30 metaphases from each culture were scored for SCE. In accord with previous studies, cigarette smoking increased SCE. The use of oral contraceptives had no influence on SCE on non-smoking and in cigarette-smoking women. Thus the results did not indicate any potential mutagenic effect of oral contraceptives.

Sister-chromatid exchanges in lymphocytes in women with cancer of the breast

Examination of sister-chromatid exchanges (SCE) in lymphocytes may be useful for the evaluation of exposure to mutagens/carcinogens. Information of a possible association between SCE and cancer is scarce. We therefore examined SCE in peripheral lymphocytes in 131 women, aged 17-90 years (median 51.8 years), coming to operation because of a tumor of the breast. Venous blood samples were cultivated during PHA stimulation in the presence of BrdU. After treatment with colcemid (R), fixation, treatment with bisbenzimide and staining with Giemsa, 30 metaphases were scored in each specimen. 52 patients with peroperatively demonstrated carcinoma of the breast had 9.39 +/- 0.17 SCE/cell and the remaining 79 women with non-malignant fibroadenomatosis had 9.88 +/- 0.18 SCE/cell. By multiple regression analysis it appeared that the character of the tumor, the patient's age, hormone treatment and preoperative examination by mammography all were without significant influence on the SCE rate. A statistically significant correlation was found between SCE and cigarette smoking. THe 45 cigarette-smoking patients had 10.49 +/- 0.23 SCE/cell compared with 9.26 +/- 0.13 SCE/cell in the 86 non-smokers. It was concluded that spontaneous SCE in lymphocytes is not an indicator of carcinoma of the breast.

A 5;7, 5;12 double reciprocal translocation in a normal mother and a 5;7 translocation with a recombinant chromosome 5 in her normal child

A phenotypically normal mother had two apparently balanced translocations involving chromosomes 5, 7, and 12. Her karyotype was 46,XX,t(5;7) (5;12) (p14q34;p14;q21), while her daughter, who was also phenotypically normal, had inherited only one of the translocations. Her karyotype was 46,XX,-5,-7,+rec(5)t(5;7) (q34;p14)mat,+der(7)t(5;7) (q34;p14)mat. The other was lost during a meiotic crossing over, giving the daughter an apparently balanced chromosome complement.

Sister chromatid exchanges in lymphocytes after anaesthesia with halothane or enflurane

The potential mutagenicity of inhalation anaesthetics was investigated by the sister chromatid exchange (SCE) test system applied to lymphocytes in peripheral blood drawn from patients before and after anaesthesia. Twenty-one women, aged 39-82 years (median 57.7 years) received halothane for 75-180 min (median 125 min). Fourteen other patients, aged 45-90 years (median 67.5 years) received enflurane for 90-180 min (median 130 min). In both groups the numbers of SCEs were unchanged immediately following anaesthesia and 5 days after. It was concluded that, by this method, comprising human cells exposed in vivo, there was no indication of mutagenic effect of short-term exposure to halothane or enflurane in anaesthetic concentrations.

A complex four-break rearrangement between chromosomes 4 and 13 resulting in a recombinant chromosome 4

A complex four-break rearrangement between chromosomes 4 and 13 was ascertained in a 10-year-old mentally retarded girl. The rearrangement was inherited from the phenotypically normal mother, who had an inverted insertion of part of the long arm of chromosome 4 into the long arm of 13 and, in addition, a pericentric inversion of the deleted 4. Meiotic crossing-over between the normal and the inverted 4 resulted in a recombinant chromosome 4, which was inherited by the proband, together with the 13/4 insertion. In this way the proband became monosomic for 4q35 leads to qter and trisomic for 4pter leads to 4p15, but she showed only minor physical malformations, as compared with other reports on the trisomy 4p syndrome. The cytogenetic findings are difficult to describe using the ISCN nomenclature.

Anthropometry in the Cri du Chat syndrome

Anthropometric and cranial X-ray measurements of 35 individuals with a 5p- karyotype showed a general growth retardation. Height, weight, circumference of the thorax, pelvic breadth, and the size of the skull, face, hands and feet were all subnormal. Only the inner canthal distance was moderately increased, especially in young individuals, but there was no true hypertelorism. The palate was not high-arched. Large and small terminal deletions produced much the same anthropometric features; and the proband's sex did not have a major influence. Age variations within parameters examined followed the developmental pattern of normal individuals. A certain phenotypical variation in the Cri du Chat syndrome may therefore be attributed to normal changes or to intrapersonal conditions.

The Cri du Chat syndrome: epidemiology, cytogenetics, and clinical features

Data for 331 cri du chat cases, including 34 Danish probands, are reviewed. The incidence nad the prevalence among the mentally retarded population amounted to 1/45,000 and 1.5/1000, respectively. No striking association with prenatal events, parental ages, or birth order could be demonstrated. There was a significant excess of females. Parental translocations were present in slightly more than 10% of the families, while more rare cytogenetic aberrations (mosaicism, rings, and de novo translocations) accounted for less than 10% of all cases. The phenotypically relevant segment has been narrowed down to the midportion of the 5p15 band. Clinical, radiologic, and dermatoglyphic features are summarized and discussed, with special attention to the abnormal cry, which persists in many older probands, and to developmental abnormalities. No obvious correlation could be detected between clinical features and the localization of the deletion. No marker locus has yet been assigned to the short arm of chromosome 5. Treatment and prevention are briefly discussed.

Measurements on hand radiographs from 32 cri-du-chat probands

Various measurements were performed on the hand radiographs of 32 Danish cri-du-chat probands. Mean pattern profiles were made for males, females, children, and adults. Metacarpal index and relative slenderness for metacarpals and proximal phalanges were calculated. The hands were smaller than in normal persons of the same sex and age. In most of the probands, the 3rd, 4th, and 5th metacarpals were disproportionately short, and the 2nd, 3rd, 4th, and 5th proximal phalanges were disproportionately long. Only 1 case had a positive metacarpal sign.

Cytologic observations in 35 individuals with a 5p- karyotype

Chromosome investigation of 35 individuals with a 5p- karyotype and their families revealed the presence of 27 apparently terminal deletions, four interstitial deletions, and four translocations, including two familial cases. Four of the probands with simple deletions and one of the mother were mosaics. Unusual chromosomal heteromorphism, as rendered visible after acridine orange staining, was observed on the short arm of chromosome 14 in two cases and, after heterochromatin staining, on chromosome 19 in one family. Measurement studies, carried out in probands with simple deletions and in two control groups, showed a short-arm loss clustering between 32% and 62% of the normal short-arm length. Using at least two complementary staining methods per proband, we found that the midportion of the 5p15 segment probably must be deleted to develop the typical clinical features of the cri du chat syndrome.

Serologic markers and chromosome variants in a pair of chimeric twins

A pair of chimeric twins, T.S. (male) and M.R. (female) first examined in 1970 are reinvestigated in order to determine if the proportions of admixture of red cells in their blood are unchanged, and if erythrocytes and leukocytes show the same percentage of admixture. T.S., M.R. and their family are investigated for HLA, serum types, and erythrocyte antigens and enzymes. A quantitative determination of 'foreign' cell populations in the blood of each twin is attempted for the systems ABO, and HLA, and for sex chromosomes in PHA stimulated lymphocytes. The results for the ABO system obtained by agglutination technique and by a double-layer immunofluorescence technique indicate that the population of M.R. erythrocytes in T.S. has decreased during the 7-year period, and is now below half the size found in 1970. Erythrocytes and leukocytes show the same percentage of admixture in both twins.

Deletion - translocation del (12) (p11) leads to (t10;12) (p13;pII)

Renewed examinatinon with improved banding techniques of a boy previously reported to have the karyotype 46, XY,del(12)(p11) revealed a translocation 46, XY,t(10;12)(p13;p11), and reexamination of a boy previously reported to have the karyotype 46,XY/46,XY,del(5)(p13) showed the same mosaicism, but with a significantly lower frequency of cells with del(5)(p13), 8% compared with 23% at the time of birth. The decrease of the frequency of cells with chromosome abnormality in mixoploids during the first years of life as found in the present case as well as in prevously reported cases is discussed.

Partial trisomy 10q occurring in a family with a reciprocal translocation t(10;18)(q25;q23)

Partial trisomy 10q was observed in an eighteen year old girl with severe mental and physical retardation, microcephaly, a high forehead, microphthalmia, antimongoloid slants, low set ears and severely malformed extremities. A balanced translocation t(10q-;18q+), present in several family members, was identified by fluorescence and thermic denaturation techniques; the break points were 10q25 and 18q23. A comparison made with seven similar cases suggests a common, phenotypical appearance which may be of diagnostic value.

A 45,XX,5-,13-,dic+ karyotype in a case of cri-du-chat syndrome

A 45,XX,5–,13–, dic+ karyotype, verified by autoradiography and fluorescence studies, was found in a nine-year-old patient with typical clinical features of the cri-du-chat syndrome. A dicentric translocation chromosome was present in 34% of about 250 lymphocyte or fibroblast metaphases examined. Twisting in the intercentromeric region, leading to criss-cross separations, might explain the presence in 4% of the cells of a 46, XX,5p– karyotype. Other metaphases showed only one centromere on the translocation chromosome, which resembled a No. 1 in 49% of the cells and a No. 2 in 10%. Fluorescence studies indicated the presence of a centromere from a No. 5 and from a No. 13, respectively, on these monocentric chromosomes, and possible mechanisms leading to these structural alterations are discussed. Translocation chromosomes differing from these main types were seen in 3% of the metaphases. A fragile site on the long arm of one chromosome No. 16 was found in the father, a paternal aunt, and her son.