Número cromossômico em espécies brasileiras de Adesmia DC. (Leguminosae-Faboideae)

Chromosome numbers of 11 South-Brazilian species of Adesmia were determined. The cytological preparations were obtained by squashing cells of root tips, using the acetic-orcein method. The chromosome number for all the species studied was 2n=20, excepting A. incana var. incana with 2n=ca.40. The counts are new for nine species, and the other two agree with the literature. It is suggested x=10 as the basic number for the genus. Up to the present only four species were cited as polyploid.

Malpighiaceae: correlations between habit, fruit type and basic chromosome number

The family Malpighiaceae presents species with different habits, fruit types and cytological characters. Climbers are considered the most derived habit, followed, respectively, by the shrubby and arboreal ones. The present study examines the relationship between basic chromosome numbers and the derivation of climbing habit and fruit types in Malpighiaceae. A comparison of all the chromosome number reports for Malpighiaceae showed a predominance of chromosome numbers based on x=5 or 10 in the genera of sub-family Malpighioideae, mainly represented by climbers with winged fruits, whereas non-climbing species with non-winged fruits, which predominate in sub-family Byrsonimoideae, had counts based on x=6, which is considered the less derived basic number for the family. Based on such data, confirmed by statistic assays, and on the monophyletic origin of this family, we admit the hypothesis that morphological derivation of habit and fruit is correlated with chromosome basic number variation in the family Malpighiaceae.

The use of fluorescence in situ hybridization in the diagnosis of hidden mosaicism: apropos of three cases of sex chromosome anomalies

FISH has been used as a complement to classical cytogenetics in the detection of mosaicism in sex chromosome anomalies. The aim of this study is to describe three cases in which the final diagnosis could only be achieved by FISH. Case 1 was an 8-year-old 46,XY girl with normal female genitalia referred to our service because of short stature. FISH analysis of lymphocytes with probes for the X and Y centromeres identified a 45,X/46,X,idic(Y) constitution, and established the diagnosis of Turner syndrome. Case 2 was a 21-month-old 46,XY boy with genital ambiguity (penile hypospadias, right testis, and left streak gonad). FISH analysis of lymphocytes and buccal smear identified a 45,X/46,XY karyotype, leading to diagnosis of mixed gonadal dysgenesis. Case 3 was a 47,XYY 19-year-old boy with delayed neuromotor development, learning disabilities, psychological problems, tall stature, small testes, elevated gonadotropins, and azoospermia. FISH analysis of lymphocytes and buccal smear identified a 47,XYY/48,XXYY constitution. Cases 1 and 2 illustrate the phenotypic variability of the 45,X/46,XY mosaicism, and the importance of detection of the 45,X cell line for proper management and follow-up. In case 3, abnormal gonadal function could be explained by the 48,XXYY cell line. The use of FISH in clinical practice is particularly relevant when classical cytogenetic analysis yields normal or uncertain results in patients with features of sex chromosome aneuploidy. Arq Bras Endocrinol Metab. 2012;56(8):545-51

Familial glioblastoma

The authors describe a family with three members affected by glioblastoma. The proband patient, a 7 year-old girl, developed a rare complication, a pulmonary metastasis. Chromosomal analysis of her peripheral blood lymphocytes showed a normal karyotype (46, XX), without structural abnormalities. Cytogenetic study of the tumor cells disclosed several abnormalities: 46, XX, 7q - / 46, XX, -2, 4p-, 7p-, +15/ 46, XX. Some aspects about genetics of glial neoplasms are discussed.