Characterization of an isodicentric Y-chromosome for the long arm in a newborn with mixed gonadal dysgenesis.
A newborn infant was referred for evaluation because of ambiguous genitalia. Examination of the genitalia revealed a hypospadiac phallus measuring 1.5 cm in length with chordee. Subtle phenotypic features consistent with Turner syndrome were present including hypertelorism, anti-mongoloid slant to the eyes, mild widening of the neck, but no definitive webbing, shield like chest and positive cubitus valgus. A pelvic and renal sonogram confirmed the presence of a uterus and normal-appearing kidneys. There was incomplete fusion of the scrotum. No gonads were palpable within the scrotal sac. The patient was assigned a female gender on the basis of the presence of a uterus, the phenotypic appearance of the genitalia and the malignant potential of the gonads. The cytogenetic findings with QFQ-banding revealed an abnormal karyotype, i.e., mos 46,X,idic(Y) (p11.2)[77]/45,X[29]/46,X,idic(Y) (p11?) [2]/ 47,XY,idic(Y)(p11.2)[2]/47,X,idic(Y)(p11.2), + idic(Y)(p11.2)[1]/46,XY[1]. The presence of an abnormal isodicentric Y-chromosome was evaluated by FISH-technique to ensure a finer characterization than routine methods. The genotype-phenotype correlation could not be established since mosaicisms of highly variable nature can exhibit an unpredictable outcome.
Kohn
B
B
Divisions of Genetics, Long Island College Hospital-SUNY Health Science Center at Brooklyn 11201, USA.
Kleyman
S M
SM
Conte
R A
RA
Macera
M J
MJ
Glassberg
K
K
Verma
R S
RS
D005260:Female; D006060:Gonadal Dysgenesis, Mixed / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D018404:Isochromosomes; D007621:Karyotyping; D012729:Sex Chromosome Aberrations / Q000235:genetics*; D014998:Y Chromosome