45,X/46,XY mosaicism: contrast of prenatal and postnatal diagnosis.
The process of prenatal diagnosis is unique in that the diagnosis and prognosis are made without seeing the patient. 45,X/46,XY mosaicism presents a special problem in this regard. The phenotype of 45,X/46,XY postnatally diagnosed children (pediatric group) was compared to that of 6 fetuses who were diagnosed from 7,000 amniocenteses (prenatal group). These amniocenteses were performed primarily because of an increased risk of chromosome abnormality. The pediatric group (age birth-18 yr) were all phenotypically abnormal, although none were mentally retarded. Seven patients presented with ambiguous genitalia, while 2 had primary amenorrhea. Sexual assignment was changed in 2. Abnormalities included rudimentary phallus, urogenital sinus, hypospadias, undescended testes, and short stature. All 9 patients required at least one surgical procedure. In contrast, the prenatally diagnosed fetuses (ages 3 months to 3 1/2 yr) were all phenotypically normal males. Four were noted to have male genitalia on ultrasonography. Thus, the phenotype of 45,X/46,XY mosaicism in prenatally diagnosed fetuses can be markedly different from that of individuals diagnosed postnatally. This must be considered when counseling patients.
Wheeler
M
M
University of Colorado Health Sciences Center, Denver.
Peakman
D
D
Robinson
A
A
Henry
G
G
D000568:Amenorrhea / Q000235:genetics; D000649:Amniocentesis; D002648:Child; D005260:Female; D005836:Genitalia, Female / Q000002:abnormalities; D005837:Genitalia, Male / Q000002:abnormalities; D006801:Humans; D008297:Male; D009030:Mosaicism; D010641:Phenotype; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012729:Sex Chromosome Aberrations