J. A. Abrisqueta

Infertility associated with two accessory bisatellited chromosomes

SummaryTwo extra bisatellited chromosome identified as inv dup (15) (pter→q11.2::q11.2→pter) were found in an oligoasthenospermic male. Analysis of Ag-staining in the proband and in one fertile brother with a normal karyotype revealed that nucleolar organizer region (NOR) activity was significantly increased in the patient. The frequency of satellite associations was also significantly higher in the index case, but no correlation was found between NOR activity and acrocentric associations. These results suggest that extra NOR activity and the elevated frequency of satellite associations could predispose to gametogenic impairment.

Ring chromosome 4 and Wolf syndrome.

SummaryA 5-day-old male child presenting some features of Wolf syndrome is studied. The analysis of his karyotype by usual techniques showed a ring chromosome of B group. This chromosome was present in most of the cells examined. By GTG banding it was identified as a No.4 chromosome, the karyotype being: 46,XY,r(4),(p15→q35). The analysis was completed by familial cytogenetic and dermatoglyphic studies.

A new contribution to the study of 22 trisomy

SummaryThe case of a 21/2-month-old male child with intrauterine distrophy features and multiple congenital malformations is presented. Cytogenetic studies of the child and his parents, completed with Q- and G-banding techniques led us to conclude that it is a case of 22 trisomy inherited from his mother.

Familial transmission of a duplication-deficiency X chromosome associated with partial Turner syndrome

A rearranged X chromosome Xqter→q13::Xp11.4→qter was found in a mother and her two daughters, who were affected with short stature, cubitus valgus and hypothyroidism. The mothers menstrual cycles were normal until the age of premenopause. Similar previously reported cases are considered in an attempt to explain the possible origin of this X recombinant, fertility and clinical traits.

New insights into the effects of extra nucleolus organizer regions

SummaryChromosome studies were carried out in four members of a sibship with a 15p+chromosome. Two carriers had normal offspring, one was unmarried, and the index case had three abortions and no live children. By means of different banding techniques, up to four satellites and four stalks could be observed on the abnormal chromosome. The Ag-I method showed from zero to four silver precipitates on the 15p+marker. Mean Ag-staining for 15p+and the ten acrocentric chromosomes were obtained in the carriers. Statistically significant differences between sibs were found. These results suggest the existence of: (a) An interindividual and intercellular variation of nucleolus organizer region (NOR) activity in man. (b) An optimal threshold of NOR activity, so that disturbances at the meiotic level could occur when it is exceeded. Our conclusions lead us to advise analysis of NOR activity in individuals with extra nucleolus organizer regions.

A case of trisomy 8 mosaicism 47, XX, + 8/46, XX

The cytogenetic study is reported of a female infant affected with several malformations and presenting a mosaicism of the type 47,XX, + 8/46,XX in her karyotype. G‐band analysis and the distribution curves of these bands were studied in order to obtain a more objective identification of trisomy 8. Results of Q‐banding, X‐chromatin and der‐matoglyphic studies are given and compared with previous reports.

C-band length variability and reproductive wastage

SummaryThe possible influence of total Y chromosome length and the C-band size variability of chromosomes 1, 9, 16, and Y, on reproductive wastage was investigated. One hundred couples with recurrent reproductive wastage and 106 control couples with at least two healthy children and no miscarriages were cytogenetically studied. Total Y chromosome length was evaluated as the Y/F index and the C-band size was analyzed quantitatively according to the linear measurement method of Baliček et al. (1977). The different degrees of mitotic contraction were corrected on the basis of the linear correlation found between heterochromatin and euchromatin length. Statistical comparison between results of Y chromosome from both samples demonstrated, in the test group, an increase in the mean value of the Y/F index, but the increase of Y C-band length did not reach significance. In addition mean values of C-band length on chromosomes 1, 9, and 16 in couples from the test group and especially those who had had two or more abortions, were lower than those in the controls. Among the latter the frequency of chromosomes included in the category of very large heterochromatin size is higher. However these length differences have been demonstrated only in specific subgroups, and in each one for a different chromosome. Our results indicated that Y chromosome length as well as C-band size variabilities are not directly related to reproductive wastage.

Patau's syndrome and 13q21q translocation.

SummaryThis paper reports the case of a one-day-old male child presenting the typical features of Pataus syndrome. The cytogenetic study by means of conventional techniques and GTG and QFQ banding techniques showed that the chromosomal pattern of the propositus was 46,XYq+,-21,+t(13q21q) 15ps+,22ps+, and that the nondisjunction that originated the translocation and trisomy had occurred in the mother.

Study of human male meiosis. II-Q-banding in pachytene bivalents.

SummaryIn continuation of the research on male human meiosis within the study of pachytene bivalents, results from the analysis of 125 cells are presented. The aim of this work is to establish Q-banding patterns and make a detailed study of chromosomere counting and distribution. To obtain Q-bands Quinacrine and Pseudoisocyanine staining techniques have been used.

Unusual chromosome 20 anomaly arising "de novo" to give dic(20)qs

SummaryAn unusual anomaly is reported involving the long arm of chromosome 20. The appropriate cytogenetic techniques showed it to be a de novo dic(20)qs.