A familial reciprocal translocation t(1;15) in three generations identified in a regular trisomy 21 patient.

The concurrence of a reciprocal translocation and an aneuploidy represent a rare coincidence and an interchromosome effect between these two events has been suggested. We report the case of a family with a t(1;15) in three generations which was identified through the evaluation ofa patient with classical trisomy 21 or Down syndrome. The cytogenetic analysis with GTG banding showed that the proband had a regular trisomy 21 and a balanced translocation t(1;15). FISH and microsatellite analysis were carried out in the family in order to discard an interchromosomal effect. The implications for genetic assessment are discussed.

Clinical delineation of a patient with trisomy 1q32.qter and monosomy 5p resulting from a familial translocation 1;5.

We describe a patient who had multiple malformations including ventriculomegaly, colpocephaly, corpus callosum, cerebellum and vermix hypoplasia, optic nerve hypoplasia, corneal opacity and congenital heart disease in whom a trisomy 1q32-qter and monosomy 5p derived from a t(1;5)mat was diagnosed by karyotype and FISH analysis. This trisomy/monosomy association has not been previously reported. The familial analysis of the translocation was carried out in four generations and its implications on the phenotype of the patient and genetic counseling are discussed.

Cytogenetic findings in 303 Mexican patients with de novo acute myeloblastic leukemia.

In this report we show the chromosomal changes seen in a group of 303 Mexican patients with de novo Acute Myeloblastic Leukemia (AML). Two hundred forty-two patients were diagnosed and treated at two hospitals affiliated with the Instituto Mexicano del Seguro Social (IMSS). These are the Centro Medico Nacional Siglo XXI and Centro Medico La Raza Hospitals; the remaining 61 patients were diagnosed and treated at the Hospital General de Mexico (HGM). Clonal abnormalities were detected in 75.6% of the patients; this result agrees with what has been reported in other large series of AML studies. The incidence of changes per hospital was similar in patients from the IMSS hospitals (72-75%), while an increase was seen in patients from the HGM (85.2%). The chromosomal changes seen in this study in order of frequency were: t(15;17)[18.8%], t(9;22)[9.2%], miscellaneous chromosomal changes (mainly rearrangements of chromosomes 1,2,3,12y17)[8.2%], abnormalities of 16q22 [7.3%], t(8;21)[6.3%], -7/del(7q)[5.6%], t(6;9)[5.3%], and abnormalities of 11q23 [4.6%]. We reported an increase in the incidence of certain types of chromosomal changes seen in cases of AML, in comparison with reports from other countries. These differences could be due to methodological variations, although ethnic, socioeconomic and nutritional differences must not be disregarded. We support this finding when comparing distribution of changes in the population of patients seen in the IMSS hospitals with those from the HGM; the main difference lies in the socioeconomic level.

[Interferon in the eradication of the Philadelphia chromosome in chronic myeloid leukemia]. / El interferón en la erradicación del cromosoma Filadelfia de la leucemia mieloide crónica.

OBJECTIVE: To evaluate if human recombinant interferon alpha (IFN) combined with chemotherapy is able to suppress the Philadelphia chromosome clone in patients with chronic myeloid leukemia (CML). MATERIAL AND METHODS: The cytogenetic evolution in 53 patients with CML in chronic phase de novo was studied. They received one of three treatment schemes: a) induction of remission with daunorubicin, vincristine, cytosine arabinose and prednisone (DOAP) and maintenance with IFN (n = 12); b) induction with busulfan (BUS) or hydroxyurea (HYDX) and maintenance with IFN (n = 26); c) induction with DOAP and maintenance with BUS (n = 15). RESULTS: The remission was seen two to six months after the start of treatment: 10 had complete remission, six a partial one, 14 a minor remission and 23 none. The 16 with complete or partial response received treatment with IFN. None of the 15 cases maintained with BUS had complete or partial response. The proportion of cases with complete response (3/12) was slightly lower in patients treated with intensive chemotherapy (BUS/HIDX/IFN) than in those receiving conventional treatment (7/26). CONCLUSIONS: Our results showed that: a) IFN in combination with chemotherapy induced partial or complete response in 30% of our cases; and b) intensive chemotherapy combined with IFN was not superior in terms of a cytogenetic response to treatment with monodrugs (BUS/HIDX) and IFN.

[Progress in the knowledge on the genetic process of sexual differentiation in humans]. / Avances en el conocimiento del proceso genético en la diferenciación sexual del humano.

In humans, the first stage of sex differentiation is determined by the sex chromosomal constitution and the genes required in the pathway leading gonadal organogenesis. The interaction of SRY, ZFY and several autosomic and X-linked genes in this process is analyzed. It has been suggested that sex-differences are present immediately after fertilization. Sex differentiation depends on a cascade of complex molecular and morphological events that occur at the appropriate time and in the correct sequence during ontogeny.

[Molecular detection of chromosome Y DNA sequences in patients with Turner's syndrome]. / Detección molecular de secuencias de ADN derivadas del cromosoma Y en pacientes con síndrome de Turner.

The presence of Y-chromosome material in the genome of phenotypic females has been associated with an increased risk of developing gonadal tumors. To assess whether DNA sequences of the Y-chromosome are present in the genome of individuals with gonadal dysgenesis and clinical features of Turner's syndrome, we have studied three patients with 45, X/46, X, + mar chromosome complement, and two Turner patients with 45, X/46, XY and 45, X karyotypes who served as positive and negative controls, respectively. Molecular detection of Y-DNA sequences was done by DNA-DNA hybridization using the specific probes pY97 and pDP1007 as well as by polimerase chain reaction. The results revealed that the marker chromosome of one of the patients contained DNA sequences from the centromeric region of the Y-chromosome in a manner similar to that found in the 45, X/46, XY patient and in the male control; the gene ZFY was negative in this patient, and was probably lost when the ring chromosome was formed. In contrast, the ring chromosomes of the other two patients did not exhibit the presence of Y-chromosome material. The results were interpreted as demonstrating the Y-chromosome origin of the ring marker in one patient with gonadal dysgenesis, and suggest an X-chromosome origin of the ring markers in the other two patients. These data further underline the relevance of practicing molecular studies in these disorders which may help to determine appropriate therapeutic strategies.

[Cytogenetic study of 22 adults and 3 children with acute lymphoblastic leukemia]. / Estudio citogenético en 22 adultos y tres niños con leucemia linfoblástica aguda.

Between 1987 and 1990 cytogenetic studies of bone marrow and lymphocytes from peripheral blood from 25 patients with de novo ALL were performed. All cases had chromosomal aberrations; however in 23 patients a normal cell line was also present. The most important structural aberrations found were: t(17;19)(q11;p13), t(2;9;22)(q34;q34;11), t(1;7)(p13;q33), t(6;11)(q26;p16), t(3;4)(q24-25;q26), t(1;12)(q23;q34), t(2;18)(q15;p12), t(2;4)(q23;q35) and t(4;11)(q21;q23). These chromosome abnormalities correlate with the response to treatment and survival and improve the identification of high-risk patients. Our study shows the presence of some chromosomal abnormalities different to those reported in the literature; however the breakpoints involved seem to be the same which suggests that these critical regions may be directly involved in the pathogenesis of these disorders.

[Familial Yqs chromosome in 4 generations]. / Yqs familiar en cuatro generaciones.

A structural aberration of the Y chromosome (Yqs) was identified in a 4-year-old child who visited a physician for right unilateral cryptorchidism. The structure of this chromosome was determined through bands C, G and NOR. The family cytogenetic study allowed for the detection of the Yqs in up to four generations. A comparison is made of the different phenotypes associated with this marker in the medical literature, concluding that this is probably due to another polymorphism of the Y chromosome.