[Mitotic and meiotic analysis of an Y-autosome translocation(author's transl)]

Y-derived sequences detected in a 45,X male by in situ hybridization

A two-month-old boy with normal genitalia and descended testes was referred for a suspected hematological disorder. Cytogenetic analysis showed a 45,X chromosome constitution. In situ hybridization with the Y-derived probe 50f (provided by Professor Marc Fellous) was performed utilizing metaphase chromosomes to determine whether Y material could be detected. A significant amount of label (17 of 150 cells) was found on chromosome 5p suggesting a 5;Y translocation. This translocation was verified by high-resolution G-banded and G-11-stained chromosomes.

Minute chromosomes replacing the Y chromosome carry Y-specific sequences by restriction fragment analysis and in situ hybridization

Two unrelated males, a 43-year-old man with azoospermia and a 4-year-old boy with stature at the 10th centile, had similar karyotypes: 46,X,min. The minutes, present in all cells analyzed, stained weakly with G-, C-, and Q-banding methods. To elucidate their origin we used molecular techniques: In HaeIII digests of total genomic DNA from both individuals, no Y-specific reiterated sequences were detected. However, restriction fragment analysis with probe pDP31 demonstrated that the patients' DNA contained the Y-specific fragment. In situ hybridization with the same probe showed that these sequences were present on the minute chromosomes and have not been translocated elsewhere.

Cytogenetic and histological studies of testicular biopsies from subfertile men with chromosome anomaly

Testicular biopsies from eight men with abnormal karyotypes have been examined for histological and cytogenetic evidence of disturbances of meiosis. Quantitative analysis of this material showed one, with a 13;14 Robertsonian translocation, to have apparently normal spermatogenesis. Three patients, one with a 47,XYY and two with 45,XY, inv 9 karyotypes, had an overall depression of spermatogenesis. Four others, all with major chromosomal abnormalities, had apparently normal spermatogenesis until the primary spermatocyte stage. Two of these had sex autosomal translocations. One, 45,Y,t(X;21), had a complete block at MI, the other, 46,X,t(Y;16), had a partial block at spermatid formation. One man with a reciprocal 2;10 translocation showed delay at all stages beyond spermatocyte formation and one man with an inversion of chromosome 3 showed impaired spermatid maturation.

Localisation of male determining factors in man: a thorough review of structural anomalies of the Y chromosome

It is widely accepted that male determination in man depends on the presence of a factor or factors on the Y chromosome. These factors may be localised within the Y chromosome through the study of structural anomalies of the Y. A thorough review of seven different structural anomalies of the Y is presented: dicentric Y chromosomes, Y isochromosomes, ring Y chromosomes, Y; autosome, Y;X, and Y;Y translocations, and Y deletions. The evidence from these studies indicates that a gene or genes on the short arm or the Y near the centromere play a crucial role in the development of the testes. A few studies indicate that one or more factors on the long arm of the Y may also influence testicular development. If such a factor is present on the long arm, then it too must be very near the centromere. The theory that separate genes independently control the initial development and maturation of the tests (on the long and short arms of the Y, respectively) may be premature. Recently proposed arguments in its favour are examined. Some evidence also indicates the presence of a fertility factor on the non-fluorescent segment of the long arm. Relevant information on the H-Y antigen is discussed.

The identification of Y chromosome translocations following Distamycin A treatment

Pretreatment of PHA-stimulated lymphocyte cultures from normal males with 100 micrograms/ml Distamycin A for the final 24 h of incubation led to a striking decondensation of the heterochromatic portion of the long arm of the Y chromosome. The despiralized region of Yq maintained its fluorescent properties in this altered morphologic state. Two cases of Y chromosome translocation (Y/22 and Y/X) were identified with this technique. A review of the literature revealed 62 similar cases in which the phenotypic-karyotypic correlations were instrumental in the prenatal counseling of the family with the Y/22 translocation.

An azoospermic male with a Y/autosome translocation

This report describes an azoospermic male carrying a Y/autosome translocation. The patient had a 46,X,t(Y;10)(q12;p13) chromosome complement in a lymphocyte culture. The cytogenetic study of this patient is described, together with testicular histology, spermiogram, hormone levels, and clinical history.

Aspermia, associated with a presumably balanced X/autosomal translocation karyotype 46, Y, t (X;5) (q28;q11)

A new case of X/autosome translocation in a male patient is described. Azoospermia and Klinefelter like stigmata can be explained as a consequence of the balanced translocation, or by disturbed X-chromosomal inactivation during spermiogenesis.