Molecular characterization of 39 de novo sSMC: contribution to prognosis and genetic counselling, a prospective study

Small supernumerary marker chromosomes (sSMCs) are structurally abnormal chromosomes that cannot be characterized by karyotype. In many prenatal cases of de novo sSMC, the outcome of pregnancy is difficult to predict because the euchromatin content is unclear. This study aimed to determine the presence or absence of euchromatin material of 39 de novo prenatally ascertained sSMC by array-comparative genomic hybridization (array-CGH) or single nucleotide polymorphism (SNP) array. Cases were prospectively ascertained from the study of 65,000 prenatal samples [0.060%; 95% confidence interval (CI), 0.042-0.082]. Array-CGH showed that 22 markers were derived from non-acrocentric markers (56.4%) and 7 from acrocentic markers (18%). The 10 additional cases remained unidentified (25.6%), but 7 of 10 could be further identified using fluorescence in situ hybridization; 69% of de novo sSMC contained euchromatin material, 95.4% of which for non-acrocentric markers. Some sSMC containing euchromatin had a normal phenotype (31% for non-acrocentric and 75% for acrocentric markers). Statistical differences between normal and abnormal phenotypes were shown for the size of the euchromatin material (more or less than 1 Mb, p = 0.0006) and number of genes (more or less than 10, p = 0.0009). This study is the largest to date and shows the utility of array-CGH or SNP array in the detection and characterization of de novo sSMC in a prenatal context.

A case of trisomy 12 mosaicism with pituitary malformation and polycystic ovary syndrome

We report the case of a patient (followed from birth to 15 years) presenting with trisomy 12 mosaicism, and focus on the endocrine phenotype associating a pituitary malformation and ovarian abnormalities. We describe the dysmorphic features and their evolution, the growth retardation and ovarian symptoms. Complete growth hormone deficiency was confirmed on auxological data, stimulation test and was related to pituitary stalk interruption, diagnosed by magnetic resonance imaging. Effect of growth hormone treatment was satisfactory resulting in a normal adult height. She also presented premature thelarche associated with right ovarian hypertrophy (4 to 5 fold the volume of the left ovary) which remained constant until 15 years of age. Diagnosis of trisomy 12 mosaicism was made on skin and ovarian karyotypes. The possible relation between these endocine findings and some genes located on chromosome 12 involved in pituitary and ovarian development is discussed.

Molecular characterization of a cryptic 2q37 deletion in a patient with Albright hereditary osteodystrophy-like phenotype

The Albright hereditary osteodystrophy-like (AHO-like) syndrome was recently defined as a rare dysmorphic syndrome including brachymetaphalangism and mental retardation. This phenotype occurs in Albright hereditary osteodystrophy (AHO) but unlike it, the level of the Gs alpha protein activity is not reduced. To date 59 patients with these clinical and biochemical features have been reported, and for the majority of them (57/59) a cytogenetically visible 2q37 deletion has been observed. We report a new case of typical AHO-like syndrome with normal karyotype. Using the polymorphic marker D2S125 we found a loss of heterozygosity suggestive of a de novo 2q37 deletion of maternal origin. This hypothesis was confirmed by FISH analysis with a subtelomeric 2q probe containing the D2S90 marker. Genotypic analysis allowed us to map the proximal breakpoint of the subtelomeric deletion within an interval delimited by D2S2338 (present) and D2S2253 (deleted). This 2q subtelomeric deletion as small as 4 Mb is to date the smallest one observed in association with a typical AHO-like phenotype, and allows us to move the centromeric boundary of the AHO-like critical region by 750 kb towards the 2q telomere.

Increased aneuploidy in spermatozoa from testicular tumour patients after chemotherapy with cisplatin, etoposide and bleomycin

Testicular cancer is the most common neoplasia occurring in the young male population. The PEB (cisplatin, etoposide and bleomycin) adjuvant chemotherapy usually proposed after orchidectomy in non seminomatous tumours, and in metastatic seminomas, has improved the long-term survival of these patients. Following an azoospermic period, sperm cell recovery is generally observed after treatment delivery, but little is known about the genetic consequences on these new spermatozoa. To estimate the chromosomal consequences of this chemotherapy on sperm cells during the period of recovery of spermatogenesis, sperm cell aneuploidy was studied in testicular cancer patients, at 6-18 months after PEB adjuvant chemotherapy delivery, using fluorescence in-situ hybridization (FISH) of chromosomes 7, 16, 18, X and Y with specific DNA probes. A significant increase in the frequency of diploidy and disomy for chromosomes 16, 18 and XY was observed in treated patients compared with a healthy control group. Spermatozoa aneuploidy occurring during the spermatogenesis recovery period might be a possible side effect of the PEB regimen. Thus, practitioners should be advised to provide counselling about the need for an appropriate duration of contraception. Moreover, genetic counselling should be offered in cases of pregnancy occurring soon after the end of chemotherapy.

Sex chromosome mosaicism in males carrying Y chromosome long arm deletions

Microdeletions of the long arm of the Y chromosome (Yq) are a common cause of male infertility. Since large structural rearrangements of the Y chromosome are commonly associated with a 45,XO/46,XY chromosomal mosaicism, we studied whether submicroscopic Yq deletions could also be associated with the development of 45,XO cell lines. We studied blood samples from 14 infertile men carrying a Yq microdeletion as revealed by polymerase chain reaction (PCR). Patients were divided into two groups: group 1 (n = 6), in which karyotype analysis demonstrated a 45,X/46,XY mosaicism, and group 2 (n = 8) with apparently a normal 46,XY karyotype. 45,XO cells were identified by fluorescence in-situ hybridization (FISH) using X and Y centromeric probes. Lymphocytes from 11 fertile men were studied as controls. In addition, sperm cells were studied in three oligozoospermic patients in group 2. Our results showed that large and submicroscopic Yq deletions were associated with significantly increased percentages of 45,XO cells in lymphocytes and of sperm cells nullisomic for gonosomes, especially for the Y chromosome. Moreover, two isodicentric Y chromosomes, classified as normal by cytogenetic methods, were detected. Therefore, Yq microdeletions may be associated with Y chromosomal instability leading to the formation of 45,XO cell lines.

Lower alkaline phosphatase activity and occurrence of an abnormal hybrid intestinal/tissue non-specific isoform in Down's syndrome amniotic fluids

Quantitative and qualitative analysis of alkaline phosphatases (AP) was performed on amniotic fluid in 59 normal pregnancies and 14 Down's syndrome (DS) pregnancies at 16, 18 and 19 weeks of gestation. In DS cases, intestinal and placental isoenzyme levels were significantly reduced (P<0.001) and the AP electrophoretic pattern was seen to be modified on polyacrylamide gel electrophoresis. A unique component was detected. After extraction and purification of the abnormal isoenzyme, peptide fragments obtained after cyanogen bromide cleavage indicated a hybrid heterodimeric AP composed of intestinal and tissue non-specific subunits, as evaluated by SDS polyacrylamide gel electrophoresis.

22q11 deletion in DGS/VCFS monozygotic twins with discordant phenotypes

22q11.2 deletion is a common genetic disorder characterised by a wide spectrum of clinical manifestations. To date no simple genotype-phenotype correlation has been established. Moreover, several reports have mentioned phenotypic discordance between monozygotic twins. No definite mechanism has been demonstrated and mosaicism, a postzygotic second hit, environmental effects and chance events have been proposed. The twinning process itself has been suspected in two cases (11, 23). We report the case of monozygous twins with a 22q11.2 deletion who are discordant for a heart defect. We found no arguments for mosaicism or twin-to-twin transfusion syndrome. The frequent discordance for heart defects in DiGeorge/Velo-cardio-facial syndromes (DGS/VCFS) does not favour the hypothesis of somatic mutations contributing to the phenotypic variation, but rather a complex interaction between genetic and environmental systems.

Evaluation of two markers of cell maturation and proliferation in cultured amniotic cells of trisomic 18 fetuses at the 15th week of gestation

Intensive studies have been conducted so far on biochemical markers available for screening of chromosome defects in obstetrical monitoring. In this paper we report further data on two protein phosphatases: alkaline phosphatase (a marker of cell maturation) and phosphotyrosine phosphatase (a marker of cell proliferation) assayed in cultured amniotic cells from fetuses with trisomy 18 at 15 weeks of gestation. Comparison with normal fetal cells showed a different behaviour for each enzyme: alkaline phosphatase was very significantly lowered while phosphotyrosine phosphatase remained a normal levels. These results provide a further enlargement of the field of biochemical markers used in the screening tests of trisomy 18.

Changes in immunological properties of neutrophil alkaline phosphatase in trisomy 21 pregnancies

Immunoreactivity, cytochemical, immunocytochemical characteristics and subcellular distribution of neutrophil alkaline phosphatase (NAP) were investigated in blood and/or smear samples from 18 women aged 23-46 years (mean 32.5 years) with trisomy 21 fetuses (17-21 weeks) and 28 women aged 20-42 years (mean 31 years) with normal fetuses (17-22 weeks). Immunochemical NAP investigations were carried out in 8 pathological and 8 normal pregnancies; cytochemical and immunocytochemical procedures were carried out in 18 pregnant women with trisomy 21 fetuses and 28 controls. NAP from women with trisomy 21 fetuses is characterized by: (1) a significant decrease in reactivity with anti-liver-type alkaline phosphatase (AP) and anti-NAP antisera; (2) low or very slight reactivity with antiplacental or anti-intestinal antibodies; (3) marked dispersion of NAP lead citrate reaction products or anti-NAP antibody colloidal gold-labelling in neutrophil cytoplasms, as detected by electron microscopy. This subcellular AP distribution (extramembranous) is different from that of normal NAP sites associated with plasma membrane, nuclear membrane and secretory vesicles. The NAP immunochemical and cytochemical characteristics suggest that neutrophils of a woman with a trisomy 21 fetus contain two AP isoenzymes: the liver/bone type and an atypical AP.

Fabry's disease: heterozygous form of different expression in two monozygous twin sisters

A 26-year-old woman presented widespread angiokeratomas predominantly in a swimsuit distribution pattern associated with acroparesthesia in all four limbs. The tentative diagnosis of Fabry's disease (FD) was confirmed by optical and electron-microscopic findings and by appropriate biochemical testing. The work-up showed ocular and renal manifestations of the disease. The monozygous twin sister of the patient was asymptomatic although she was shown to be heterozygous for the enzymatic defect. These 2 cases illustrate the concept of extreme lyonization which can explain observed phenotypic differences in heterozygous females with X-linked hereditary diseases. The father and mother of the patient were shown to be noncarriers of the trait, suggesting de novo mutation in the twin pregnancy. However, biochemical testing for the detection of FD heterozygous females cannot rule out the possibility of the mother being heterozygous with normal enzyme activity.

Prognostic significance of karyotype in a twelve-year follow-up in childhood acute lymphoblastic leukemia

We report a follow-up of 49 children with acute lymphoblastic leukemia (ALL) diagnosed between 1972 and 1978 (follow-up 12-18 years). This series allowed us to analyze the predictive value of karyotype in a long-term follow-up. Karyotypes were abnormal in 33 cases (67.3%): pseudodiploidy in 11 (22.4%), hyperdiploidy > 50 chromosomes in 8 (16.3%), hyperdiploidy 47-50 chromosomes in 11 (22.4%), and hypodiploidy in 3 cases (6.1%). Event-free survival (EFS) and survival studies showed that the outcome of patients was determined only by treatment and karyotype. Eleven patients have survived, nine in first remission (6 years 5 months to 15 years 2 months), and two are in second remission (3 years 8 months and 8 years 2 months). All ploidy groups are represented in these patients. Late relapses can occur in the hyperdiploid > 50 group, thus accounting for shorter EFS than expected, but because of the unusually long second remission of one patient, the rate of surviving patients was higher for this ploidy group than for all other ploidy groups together. Conversely, patients with only numerical abnormalities (no matter which ploidy group they belonged to), had a better outcome than did patients with structural changes or normal karyotypes and no discrepancy between EFS and survival curves was observed in this chromosomal group. Thus, our results suggest that numerical changes only should be considered an indicator of low risk factor, but our results, based on partially banded karyotypes, need to be verified by a current method and therapy.

t(9;11)(p22;q23) translocation in blastic phase of chronic myeloid leukemia

A patient with chronic myeloid leukemia showed clonal karyotypic evolution, with the appearance of an i(17q) and t(9;11)(p22;q23). This case sheds light upon leukemogenic events related to t(9;11)(p22;q23). The presence of t(9;22) and t(9;11) in the same clone showed that t(9;11) may affect a pluripotent stem cell, thus accounting for t(9;11) in both lymphoid and monocytic leukemias. In this patient, t(9;11) could not be related to a prior cytotoxic exposure and was instead the result of natural evolution of chronic myeloid leukemia. Furthermore, this led us to assume that the phenotype of blast cells may be determined by a chromosome abnormality. A phenotypic conversion from myeloblastic to undifferentiated morphologic aspect was observed when t(9;11) was detected, suggesting that t(9;11) may have induced a loss in differentiation of blast cells affected by this change. This assumption is in agreement with the putative presence of genes activated in pluripotent progenitors by 11q23 rearrangements.

[Role and contribution of karyotyping in male infertility]

In the context of the aetiological investigation of male infertility, the authors stress the place and the contribution of blood karyotype testing in the light of their personal experience based on 1,612 subjects. This examination has an important place, as about 15% of azoospermic subjects and 6 to 7% of subjects with oligospermia less than 10 million spermatozoa per ml, either alone or in combination with other abnormalities of the semen examination, present a congenital chromosomal abnormality. A remarkable constancy of the results was observed according to identical recruitment criteria. The contribution of this examination is also important: the medical and psychological value of detecting the cause of azoospermia, genetic counselling and antenatal chromosomal diagnosis for non-azoospermic subjects with an equilibrated structural abnormality, in whom treatment allows a chance of procreation, genetic counselling for the family of these subjects in order to prevent the appearance of a chromosomally abnormal infant. In conclusion, the authors argue in favour of the routine use of this test in all infertile subjects with at least isolated oligospermia less than 10 million spermatozoa per ml.

Alkaline phosphatase and phosphotyrosine phosphatase activities of cultured amniotic cells with trisomy 18

In cultured amniotic cells from fetuses with Edward's syndrome (trisomy 18), the activities of two protein phosphatases, alkaline phosphatase and phosphotyrosine phosphatase, were measured. Comparison with normal fetal cells showed a different behavior for each enzyme. Alkaline phosphatase was significantly lowered while phosphotyrosine phosphatase remained at normal levels. The interest of these enzyme assays in the screening procedure of this severe chromosome defect is discussed.

Difference in activity properties and subcellular distribution of neutrophil alkaline phosphatase between normal individuals and patients with trisomy 21

Biochemical, cytochemical characteristics and electron microscopy subcellular distribution of neutrophil alkaline phosphatase (NAP) were analysed in blood and/or smear samples from 39 trisomy 21 patients (Down's syndrome) aged 11.5-18 years (mean 15.5 years) and 55 normal subjects aged 12-20.5 years (mean 17 years). All patients were karyotyped. NAP cytochemical procedures were carried out on all subjects; biochemical NAP determinations were made in 10 patients and 20 controls; ultrastructural electron microscopy of AP was performed in three patients and four normal subjects. Neutrophil alkaline phosphatase from patients with trisomy 21 displayed the following changes: (1) a significant increase of enzyme activity, (2) a high thermal lability of enzyme. Electron microscope morphology exhibited large deposits of NAP reaction product associated with the plasma membrane and intracellular main organelles, like phosphasomes. The NAP biochemical and cytochemical characteristics suggest that trisomy 21 neutrophils contain a non-specific AP isoenzyme, closely related to the early placental form.

Heat resistance, immunological and quantitative changes of neutrophil alkaline phosphatase in trisomy 21 pregnancies

Neutrophil alkaline phosphatase (NAP) was analysed in 25 pregnant women with trisomy 21 foetuses whose chromosomal aberration was recognized by cytogenetic study after amniocentesis. Enzyme investigation was performed at 20-22 weeks of gestation using cytochemical and biochemical techniques. Twenty-nine women at the same stage of normal pregnancies were selected as controls. In parallel, each mother was karyotyped. Ten subjects from each series underwent biochemical and immunological investigation: measurement of enzyme levels, thermostability study and immunological tests with alkaline phosphatase isoenzyme antibodies. NAP from pregnant women with trisomy 21 foetuses was characterized by: (1) a lower rate of enzyme activity, (2) a large amount of heat-stable enzyme (T = 56 degrees C for biochemical assays, T = 85 degrees C for cytochemical tests), and (3) a marked loss of liver antigenicity. These findings suggest the presence in trisomy 21 pregnancies of a non-specific alkaline phosphatase isoenzyme which appears as an "enzyme marker" in maternal circulating neutrophils.

Association of the Philadelphia chromosome and 5q- in secondary blood disorder

A patient developed a secondary blood disorder 7 years after radiotherapy for a gastric lymphoma. The initial myelodysplastic syndrome evolved to a myeloproliferative phase with transient polycythemia, progressive thrombocythemia, and hyperleukocytosis. Chromosome analysis performed in the terminal phase showed del(5)(q13q31),t(9;22)(q34;q11), and a complex rearrangement involving chromosomes #2 and #3. A correlation between chromosomal abnormalities and hematologic findings could be established. In this case, we have assumed that the Philadelphia translocation is a late event, due to prior mutagen exposure, and its association with a common secondary abnormality (5q-), followed by a progressively developing myeloproliferative phase. Furthermore, the association of Ph and 5q- in a single clone seems to indicate that the same stem cell is affected by these two abnormalities.

An enzymatic marker in mothers of trisomy 21 children: neutrophil alkaline phosphatase

Neutrophil alkaline phosphatase (NAP) from 12 mothers of normal children was investigated and the results compared to those of 7 mothers with trisomy 21 offsprings, in an attempt to determine a parental molecular change in this chromosomal abnormality. The biochemical properties of the enzyme were analyzed by the procedures of isoenzyme characterization, i.e. enzyme assays, thermostability, inhibition patterns and slab gel electrophoresis. Immunological properties were determined on 5 samples from normal mothers and on the same sample number of mothers with affected children. In these latter NAP showed characteristics that were to some extent different from the ones of normal controls. The following changes were observed: highly significant loading of membrane and nucleus pellets in NAP activity, poor effect of inhibitors on thermostable component and immunodepletion measured by a significant decrease of the normal affinity for antiliver and antiplacental alkaline phosphatase antisera. These findings are discussed in the light of our knowledge of alkaline phosphatase isoenzymes.

[Chromosome anomalies and male infertility. A study of 1,444 subjects]

Chromosomal anomaly was detected in 7.6% of a cytogenetic survey of 1,444 infertile male azoospermia or oligozoospermia with a sperm count below 20 million/ml. Anomalies are especially of the sex-chromosome and of autosomal robertsonian translocation type. Distribution of these subjects on account of the sperm count has pointed out an increase of chromosomal anomalies in inverse ratio to the sperm count.

[Value of chromosome tests in genetic counseling of infertile couples]

A cytogenetic analysis of more than 7000 subjects has been performed in the aetiological screening of infertile couples. This study revealed that infertile couples can be divided into three groups: those with one or more spontaneous abortions before 13 weeks of gestations, those with primary sterility (no gestation for at least 24 months) or those with secondary sterility (after one or more children, no further gestation for at least 24 months). The frequency of chromosomal abnormalities observed in this population is 2,9%, i.e. 1/17 couple. The results, according to sex of subjects bearing the chromosomal abnormality, were then analysed in each of the three groups. From this study, the authors insist on the advantage of systematically performing a chromosome analysis in the case of infertile couples for two main reasons: frequency of chromosomal abnormalities is relatively high in this population, detection of such abnormalities enables some couple to be rapidly directed to other solutions (Artificial Insemination), and others, due to prenatal chromosomal diagnosis, to have offspring in safety.

Chromosome studies in 2136 couples with spontaneous abortions

Two thousand one hundred and thirty six couples with one or more spontaneous abortions (SAB) before 13 weeks of gestation and with or without one normal liveborn child (NLC) were karyotyped. In 4.31% of the couples one partner was a carrier of a major chromosomal abnormality. Couples with SAB only have 2-fold more chromosomal aberrations than couples with SAB and NLC. A correlation between the frequency of chromosomal abnormalities and the number of SAB was observed. Finally, the various types of chromosome aberrations were analysed.

t(14;14)(q11;q32) in biphenotypic blastic phase of chronic myeloid leukemia

A blastic crisis of chronic myeloid leukemia without a detectable chronic phase is reported. At diagnosis, blast cells present t(9;22)(q34;q11),t(14;14)(q11;q32) translocations and early B cell phenotype (DR +, TdT +, B4 +, BA1 +, J5 +). At relapse, the malignant clone evolves to a biphenotypic expression, the initial markers remain unchanged, and two myeloid antigens (My 7, My 9) appear. The wide overlap in percentages of blast cells displaying lymphoid and myeloid markers shows that a single clone bears antigens of both lineages. Simultaneous occurrence of a t(14;14)(q11;q32) translocation, usually found in T cell malignancies, and of a B cell phenotype raises the question of the relationship between chromosomal changes and surface marker expression. The malignant cell is assumed to be a progenitor cell, already committed to lymphoid lineage and retaining the potential to switch to myeloid lineage.

Chromosome studies in 952 infertile males with a sperm count below 10 million/ml

A major chromosomal abnormality was observed in 10.3% of subfertile men in this study. This result is similar to a previous survey using the same criteria for selection of probands. The high frequency of chromosomal abnormalities emphasizes the importance of cytogenetic examination in subfertile men. The detection of such an abnormality should be followed by chromosome analysis in the patient's family. Prenatal diagnosis is indicated if a subfertile man with an abnormal karyotype fathers a child.

[Trisomy 12(pter----q12) and monosomy 21(pter----q21). A propos of a case]

The authors report an observation of a child with both trisomy 12(pter----q12) and monosomy 21(pter----q21). It is thus possible to detect the clinical signs which can be attributed to trisomy 12p and to monosomy 21ql respectively. The authors point out the originality of the maternal translocation which differs from the translocations affecting these two chromosomes previously described in the literature. Finally, the rarity of the type of adjacent-2 segregation is shown, and discussed according to the literature already published.

Cytochemical and biochemical studies on neutrophil alkaline phosphatase in parents of trisomy 21 children

A study of karyotypes and neutrophil alkaline phosphatase (NAP) was carried out for 66 parents (33 couples) of trisomy 21 children and for 60 control parents (30 couples). Enzyme activity was determined simultaneously by biochemical and cytochemical techniques. In the mothers of trisomy 21 children we found: (a) by biochemical techniques, a significant increase of NAP activity in polymorphonuclear leukocyte (PMN) homogenates (P less than 0.01) and a lower supernatant/pellet ratio (P less than 0.01); (b) by cytochemical techniques (with or without thermal and urea treatments) NAP activity was significantly higher (P less than 0.001) than in control mothers; in the fathers, the two techniques gave normal NAP activity results.

[Secondary 18q2 due to a paternal double translocation]

Trisomy 18q2 in a boy associated with a reciprocal translocation due to a paternal balanced complex rearrangement interesting chromosome 9, 10 and 18 is reported. Using this observation phenotypical data of the "typical" clinical description are discussed and some particular signs are pointed out. About the occurrence of the complex chromosomal rearrangement different hypothesis are considered.

Neutrophil alkaline phosphatase in children with trisomy 21 and their parents

A comparative study of karyotypes and neutrophil alkaline phosphatase (NAP) was carried out for 70 parents (35 couples) of trisomy 21 children and their 35 trisomy 21 children and for 110 control parents (55 couples) and their normal children. In the trisomy 21 families we found a significant increase in NAP: mother P less than 10-4; father P less than 10-4; children P less than 10-9; the NAP level in affected child is approximately equal to the sum of the NAP levels of the two parents (P = 0.80; sigma2 = 5%). In one parent of a trisomy 21 child, a karyotype anomaly was present.

[Association of male XX with Pierre Robin syndrome in a child whose father has a balanced 46XY, t (16; 17) (p13;q21) translocation]

The authors relate the association XX male and syndrome of Pierre Robin in a child whose father presents a reciprocal equilibrated translocation 46,XY t (16;17) (p13;q21). They discuss the possible relation between these different anomalies and notably the possibility of a genic effect.

Increase of neutrophil alkaline phosphatase in the parents of trisomy 21 children. Hematological and cytogenetic studies

A comparative study of karyotypes, hematological variables and neutrophil alkaline phosphatase (NAP) was performed in 106 parents (53 couples) of children with free, homogeneous trisomy 21 and of 220 parents (110 couples) of normal children. In the parents of trisomy 21 children we found a significant increase of the NAP (p <0.05) and a nonsignificant difference in the number of white blood cells. In 4 cases, we also found an anomaly in the karyotype. A modification of the metabolism of the neutrophils seems possible.

[Partial trisomy 10p of paternal origin. 2 new cases in 2 different families]

Two unrelated patients with partial trisomy 10p due to a paternal balanced translocation are reported. Though the sizes of the trisomic segment are not identical, both patients show: severe growth retardation, important psychomotor retardation and a dysmorphic mouth recalling a "tortois mouth". These observations are compared to twelve others from the literature.

[Cytogenetics of Paget's disease of bone]

The authors studied the karyotype in blood and marrow of 34 patients with Paget's disease and compared the results with those of a control group of the same age. Structural abnormalities are more frequent in the blood than in the marrow, but there is no significant difference in comparison with the abnormalities in the control group. Ionizing radiations and drugs do not seem to be responsible for the abnormalities encountered. The numerical abnormalities are characterized by an increase in the number of hypodiploidies, particularly involving the chromosome groups A, B and D, whereas chromosomal damage affecting the C and G groups is less than normal. These abnormalities were encountered in a limited number of patients. The authors discuss the significance of these chromosomal abnormalities in the more general context of the genetics of Paget's disease.