FISH and PCR analyses in three patients with 45,X/46,X,idic(Y) karyotype: clinical and pathologic spectrum

Objective. – To delineate the phenotypic spectrum (clinical and gonadal features) from patients with a 45,X/46,X,mar(Y) karyotype based upon of their clinical, histological, cytogenetic and molecular evaluation.

Subjects. – Three patients with a 45,X/46,X,mar(Y) karyotype.

Methods. – Clinical assessment, karyotyping, endocrine evaluation, FISH and PCR analyses of several Y-chromosome loci and direct sequencing of the SRY gene.

Results. – The patients, two males and one female had varying degrees of impairment of sexual differentiation, with or without testis formation. One patient (reared as female and aged 17 years) had Turner syndrome with bilateral streak gonads. The second patient (2.4 years old) had ambiguous genitalia and presented a dysgenetic testis with a contralateral streak gonad. A third patient (26 years old) had bilateral dysgenetic testes (dysgenetic male pseudohermaphroditism). The ratio of 45,X vs. 46,X,+mar(Y) cells differed between patients and between different tissues. In each case the marker sexual chromosome was identified as a rearranged Y-chromosome (idic(Y)) using FISH and PCR analyses. In all cases the SRY gene was present in all tissues studied. No mutations were identified in this gene in any of the patients.

Conclusions. – The extent of male or female differentiation in these patients depends in part on the prevalence, time occurrence, and distribution of the 45,X cell line.