DNA analysis of two patients with a non-fluorescent y chromosome

A 12 1/2‐month‐old girl was referred because of short stature, short neck, large internipple distance and simian crease on her right hand. By routine cytogenetic techniques the presence of an unidentifiable marker chromosome and loss of one X chromosome was noted (i.e. 45, X/46, X, mar/47, X, mar, +mar). By fluorescence in situ hybridization (FISH) technique, the marker chromosome was identified as an isodicentric non‐fluorescent Y chromosome ((45, X/46, X, idic (Ynf)/47, X, idic (Ynf), +idic (Ynf)). Although the clinical significance of this finding cannot be assessed at present, possible development of gonadoblastoma in such cases is a major concern and warrants follow‐up evaluations.

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“…Recently, a number of approaches have been taken to characterize marker chromosomes (Speleman et al 1990, Sekine et al 1992.…”

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confidence: 99%

Identification of a non‐fluorescent isodicentric Y chromosome by molecular cytogenetic techniques

Macera¹,

Sherman²,

Shah³

et al. 1994

Clinical Genetics

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Detection of Y chromosome sequences in a 45,X/46,XXq– patient by Southern blot analysis of PCR‐amplified DNA and fluorescent in situ hybridization (FISH)

et al. 1995

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In some cases of gonadal dysgenesis, cytogenetic analysis seems to be discordant with the phenotype of the patients. We have applied techniques such as Southern blot analysis and fluorescent in situ hybridization (FISH) to resolve the phenotype/genotype discrepancy in a patient with ambiguous genitalia in whom the peripheral blood karyotype was 45,X. Gonadectomy at age 7 months showed the gonadal tissue to be prepubertal testis on the left side and a streak gonad on the right. The karyotype obtained from the left gonad was 45,X/46,XXq- and that from the right gonad was 45,X. Three different techniques, PCR amplification, FISH, and chromosome painting for X and Y chromosomes, confirmed the presence of Y chromosome sequences. Five different tissues were evaluated. The highest percentage of Y chromosome positive cells were detected in the left gonad, followed by the peripheral blood lymphocytes, skin fibroblasts, and buccal mucosa. No Y chromosomal material could be identified in the right gonad. Since the Xq- chromosome is present in the left gonad (testis), it is likely that the Xq- contains Y chromosomal material. Sophisticated analysis in this patient showed that she has at least 2 cell lines, one of which contains Y chromosomal material. These techniques elucidated the molecular basis of the genital ambiguity for this patient. When Y chromosome sequences are present in patients with Ullrich-Turner syndrome or gonadal dysgenesis, the risk for gonadal malignancy is significantly increased. Hence, molecular diagnostic methods to ascertain for the presence of Y chromosome sequences may expedite the evaluation of patients with ambiguous genitalia.

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Human Y Chromosome Function in Male Germ Cell Development

Vogt¹

1996

Advances in Developmental Biology (1992)

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DNA analysis of two patients with a non-fluorescent y chromosome

Cited by 3 publications

References 14 publications

Identification of a non‐fluorescent isodicentric Y chromosome by molecular cytogenetic techniques

Identification of a non‐fluorescent isodicentric Y chromosome by molecular cytogenetic techniques

Detection of Y chromosome sequences in a 45,X/46,XXq– patient by Southern blot analysis of PCR‐amplified DNA and fluorescent in situ hybridization (FISH)

Human Y Chromosome Function in Male Germ Cell Development

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