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Free β-hCG as first-trimester marker for fetal trisomy
1480
required for a marriage licence in Beijing, China, an area not known for sexual promiscuity. Swabs from the inner aspects of the labia minora were taken with a swab moistened with sterile saline. HPV DNA (types 6, 11, 16, and 18) was determined by PCR,7,8 HPV DNA was found in vulvar swab cell specimens from 9 (15%) of young women without experience of sexual intercourse. In those with such experience (monogamously) 7 (12%) specimens were positive for HPV DNA. This difference in prevalence is not significantly different (95% CI -0-165 to +0-215). It is unlikely that the HPV-positive virgins had had other forms of sexual or genital contact that could lead to transmission of HPV, because HPV was not recovered from their husbands-to-be. However, it is possible what we are seeing here represents a very low level of HPV present in subclinically infected individuals. Either way we have found genital HPV independently of the sexual experience of these young adult women. Whether these HPV infections reflect childhood infection through vertical transmission6 or transmission by family or working environmental contacts remains to be determined. It seems that HPV is not always transmitted sexually, and that routes other than sexual intercourse exist for HPV transmission in adults. Understanding them may help to prevent HPV infections.
Supported by medical research grants CMRP-235 and CMRP-286 from Chang Gung College and Memorial Hospital, both to C. C. P. Departments of Biochemistry and Obstetrics and Gynaecology, Chang Gung Medical College and Memorial Hospital, Taipei, Taiwan, Republic of China
CHIA C. PAO PEI LING TSAI YA-LI CHANG T’SANG-T’ANG HSIEH
Free
(3-hCG levels (MoM) in 5 cases of trisomy 18 and 13 cases of
trisomy 21
at 7-13 weeks’
gestation.
Medians for each week were derived by weighted log regression. Data from the cases of trisomy expressed as multiples of the median (MoM) are shown in the figure. The median value in 13 cases of trisomy 21 was 1-85, being significantly greater (p=0’0017, Mann-Whitney U-test) than in unaffected cases. The median value in trisomy 18 was 0-17, being significantly lower (p 0-0021) than in unaffected cases. This study indicates that measurement of maternal serum free (3-hCG may provide a method for screening for trisomies 18 and 21 =
Department of Obstetrics and Gynaecology, Beijing Friendship Hospital, Beijing, People’s Republic of China
JIA YU JIN
Howley PM. Role of the human papillomaviruses in human cancer. Cancer Res 1991; 51 (suppl): 5019-22s. 2. Ley C, Bauer HM, Reingold A, et al. Determinants of genital human papillomavirus infection in young women. J Natl Cancer Inst 1991; 83: 997-1003. 3. Chang YL, Lin CY, Tseng CJ, Cheng HS, Lin HC, Pao CC. Prevalence of genital human papillomavirus infections in sexually transmitted disease clinic. Eur J Clin Microbiol Infect Dis (in press). 4. Jenison SA, Yu XP, Valentine JM, et al. Evidence of prevalent genital-type human papillomavirus infections in adults and children. Infect Dis 1990; 162: 60-69. 5. Sedlacek TV, Lindheim S, Eder C, et al. Mechanism for human papillomavirus transmission at birth. Am J Obstet Gynecol 1989; 161: 55-59. 6. Tseng CJ, Lin CY, Wang RL, et al. Possible transplacental transmission of human papillomavirus. Am J Obstet Gynecol 1992; 166: 35-40. 7. Pao CC, Lin CY, Maa JS, Lai CH, Wu Sy, Soong YK. Detection of human papillomavirus in cervicovaginal cells using polymerase chain reaction. J Infect Dis 1990; 161: 113-15. 8. Pao CC, Lin SS, Lin CY, Maa JS, Lai CH, Hsieh TT. Identification of human papillomavirus DNA sequences in peripheral blood mononuclear cells. Am J Clin Pathol 1991; 95: 540-46. 1.
Free
&bgr;-hCG as first-trimester marker for
fetal trisomy SiR,—The concentration of free p-subunit of human chorionic gonadotropin ((3-hCG) in maternal serum is a valuable marker in second-trimester Down syndrome screening, achieving detection rates of 80% with a false-positive rate of 5-5%, when combined multivariately with maternal serum a-fetoprotein and maternal age.1-s In side-by-side comparison studies2,3 with total hCG, the free 0-subunit has emerged as the better marker. However, in the first
trimester maternal
serum
total hCG is
not
increased in Down
syndrome pregnancies.6,7 We have had the opportunity to measure free p-hCG in unselected samples collected prospectively from women in the first trimester. Blood was collected from a consecutive group of 12 700 women attending antenatal clinics between the 7th and 13th weeks of gestation. The serum was separated and stored at -20°C until the pregnancy outcome was known. Among these 12 700 pregnancies, 13 cases of trisomy 21 and 5 of trisomy 18 were cytogenetically confirmed after second-trimester maternal serum screening* or as a result of term delivery of an affected infant. From the unaffected cases, 40 samples at each gestational week from 7 to 13 were selected at random and analysed for free (3-hCG.9
during the first trimester of pregnancy. Endocrine Unit, Clinical Biochemistry Oldchurch Hospital, Romford, Essex
Department,
K. SPENCER
Research Division, NTD Laboratories, New York, NY, USA
J. N. MACRI
Duncan Guthrie Institute of Medical Genetics,
D. A. AITKEN J. M. CONNOR
Yorkhill,
Glasgow
G3 8SJ, UK
1. Macri JN, Kasturi RV, Krantz DA, et al. Maternal serum Down syndrome screening: free beta protein is a more effective marker than human chorionic gonadotropin. Am J Obstet Gynecol 1990; 163: 1248-53. 2. Spencer K. Evaluation of an assay of the free beta subunit of choriogonadotropin and its potential value in screening for Down’s syndrome. Clin Chem 1991; 37: 809-14. 3. Spencer K, Macri JN. Early detection of Down’s syndrome using free beta human choriogonadotropin. Ann Clin Biochem (in press). 4. Spencer K, Coombes EJ, Mallard AS, Milford Ward A. Free beta human choriogonadotropin in Down’s syndrome screening: a multicentre study ofits role compared with other biochemical markers. Ann Clin Biochem (in press). 5. Spencer K, Carpenter P. Risk of Down’s syndrome and amniocentesis rate. Br Med J 1992; 304: 640-41. 6. Cuckle HS, Wald JN, Barkai G, et al. First trimester biochemical screening for Down syndrome. Lancet 1988; ii: 851-52. 7. Brock DJH, Barron L, Holloway S, Liston WA, Hillier SG, Seppala M. First trimester maternal serum biochemical indicators in Down syndrome. Prenat Diagn
1990; 10: 245-51. 8. Crossley JA, Aitken DA, Connor JM. Prenatal screening for chromosome abnormalities using maternal serum chorionic gonadotrophin, alpha-fetoprotein, and age. Prenat Diagn 1991; 11: 83-101. 9. Macri JN, Spencer K, Anderson R, Cook EJ. Free beta chorionic gonadotropin: a cross reactivity study of two immunometric assays used in prenatal maternal serum screening for Down syndrome. Clin Chem (in press).
Non-echogenic nuchal oedema as a marker in trisomy 21
screening
SiR.—Dr Schulte-Vallentin and Dr Schindler (April 25, p 1053) report the detection of trisomy 21 early in pregnancy through ultrasonographic demonstration of a prominent non-echogenic nuchal oedema, measuring about 4-7 mm in diameter. In a prospective study, started in 1990, 1430 patients were referred to
required for a marriage licence in Beijing, China, an area not known for sexual promiscuity. Swabs from the inner aspects of the labia minora were taken with a swab moistened with sterile saline. HPV DNA (types 6, 11, 16, and 18) was determined by PCR,7,8 HPV DNA was found in vulvar swab cell specimens from 9 (15%) of young women without experience of sexual intercourse. In those with such experience (monogamously) 7 (12%) specimens were positive for HPV DNA. This difference in prevalence is not significantly different (95% CI -0-165 to +0-215). It is unlikely that the HPV-positive virgins had had other forms of sexual or genital contact that could lead to transmission of HPV, because HPV was not recovered from their husbands-to-be. However, it is possible what we are seeing here represents a very low level of HPV present in subclinically infected individuals. Either way we have found genital HPV independently of the sexual experience of these young adult women. Whether these HPV infections reflect childhood infection through vertical transmission6 or transmission by family or working environmental contacts remains to be determined. It seems that HPV is not always transmitted sexually, and that routes other than sexual intercourse exist for HPV transmission in adults. Understanding them may help to prevent HPV infections.
Supported by medical research grants CMRP-235 and CMRP-286 from Chang Gung College and Memorial Hospital, both to C. C. P. Departments of Biochemistry and Obstetrics and Gynaecology, Chang Gung Medical College and Memorial Hospital, Taipei, Taiwan, Republic of China
CHIA C. PAO PEI LING TSAI YA-LI CHANG T’SANG-T’ANG HSIEH
Free
(3-hCG levels (MoM) in 5 cases of trisomy 18 and 13 cases of
trisomy 21
at 7-13 weeks’
gestation.
Medians for each week were derived by weighted log regression. Data from the cases of trisomy expressed as multiples of the median (MoM) are shown in the figure. The median value in 13 cases of trisomy 21 was 1-85, being significantly greater (p=0’0017, Mann-Whitney U-test) than in unaffected cases. The median value in trisomy 18 was 0-17, being significantly lower (p 0-0021) than in unaffected cases. This study indicates that measurement of maternal serum free (3-hCG may provide a method for screening for trisomies 18 and 21 =
Department of Obstetrics and Gynaecology, Beijing Friendship Hospital, Beijing, People’s Republic of China
JIA YU JIN
Howley PM. Role of the human papillomaviruses in human cancer. Cancer Res 1991; 51 (suppl): 5019-22s. 2. Ley C, Bauer HM, Reingold A, et al. Determinants of genital human papillomavirus infection in young women. J Natl Cancer Inst 1991; 83: 997-1003. 3. Chang YL, Lin CY, Tseng CJ, Cheng HS, Lin HC, Pao CC. Prevalence of genital human papillomavirus infections in sexually transmitted disease clinic. Eur J Clin Microbiol Infect Dis (in press). 4. Jenison SA, Yu XP, Valentine JM, et al. Evidence of prevalent genital-type human papillomavirus infections in adults and children. Infect Dis 1990; 162: 60-69. 5. Sedlacek TV, Lindheim S, Eder C, et al. Mechanism for human papillomavirus transmission at birth. Am J Obstet Gynecol 1989; 161: 55-59. 6. Tseng CJ, Lin CY, Wang RL, et al. Possible transplacental transmission of human papillomavirus. Am J Obstet Gynecol 1992; 166: 35-40. 7. Pao CC, Lin CY, Maa JS, Lai CH, Wu Sy, Soong YK. Detection of human papillomavirus in cervicovaginal cells using polymerase chain reaction. J Infect Dis 1990; 161: 113-15. 8. Pao CC, Lin SS, Lin CY, Maa JS, Lai CH, Hsieh TT. Identification of human papillomavirus DNA sequences in peripheral blood mononuclear cells. Am J Clin Pathol 1991; 95: 540-46. 1.
Free
&bgr;-hCG as first-trimester marker for
fetal trisomy SiR,—The concentration of free p-subunit of human chorionic gonadotropin ((3-hCG) in maternal serum is a valuable marker in second-trimester Down syndrome screening, achieving detection rates of 80% with a false-positive rate of 5-5%, when combined multivariately with maternal serum a-fetoprotein and maternal age.1-s In side-by-side comparison studies2,3 with total hCG, the free 0-subunit has emerged as the better marker. However, in the first
trimester maternal
serum
total hCG is
not
increased in Down
syndrome pregnancies.6,7 We have had the opportunity to measure free p-hCG in unselected samples collected prospectively from women in the first trimester. Blood was collected from a consecutive group of 12 700 women attending antenatal clinics between the 7th and 13th weeks of gestation. The serum was separated and stored at -20°C until the pregnancy outcome was known. Among these 12 700 pregnancies, 13 cases of trisomy 21 and 5 of trisomy 18 were cytogenetically confirmed after second-trimester maternal serum screening* or as a result of term delivery of an affected infant. From the unaffected cases, 40 samples at each gestational week from 7 to 13 were selected at random and analysed for free (3-hCG.9
during the first trimester of pregnancy. Endocrine Unit, Clinical Biochemistry Oldchurch Hospital, Romford, Essex
Department,
K. SPENCER
Research Division, NTD Laboratories, New York, NY, USA
J. N. MACRI
Duncan Guthrie Institute of Medical Genetics,
D. A. AITKEN J. M. CONNOR
Yorkhill,
Glasgow
G3 8SJ, UK
1. Macri JN, Kasturi RV, Krantz DA, et al. Maternal serum Down syndrome screening: free beta protein is a more effective marker than human chorionic gonadotropin. Am J Obstet Gynecol 1990; 163: 1248-53. 2. Spencer K. Evaluation of an assay of the free beta subunit of choriogonadotropin and its potential value in screening for Down’s syndrome. Clin Chem 1991; 37: 809-14. 3. Spencer K, Macri JN. Early detection of Down’s syndrome using free beta human choriogonadotropin. Ann Clin Biochem (in press). 4. Spencer K, Coombes EJ, Mallard AS, Milford Ward A. Free beta human choriogonadotropin in Down’s syndrome screening: a multicentre study ofits role compared with other biochemical markers. Ann Clin Biochem (in press). 5. Spencer K, Carpenter P. Risk of Down’s syndrome and amniocentesis rate. Br Med J 1992; 304: 640-41. 6. Cuckle HS, Wald JN, Barkai G, et al. First trimester biochemical screening for Down syndrome. Lancet 1988; ii: 851-52. 7. Brock DJH, Barron L, Holloway S, Liston WA, Hillier SG, Seppala M. First trimester maternal serum biochemical indicators in Down syndrome. Prenat Diagn
1990; 10: 245-51. 8. Crossley JA, Aitken DA, Connor JM. Prenatal screening for chromosome abnormalities using maternal serum chorionic gonadotrophin, alpha-fetoprotein, and age. Prenat Diagn 1991; 11: 83-101. 9. Macri JN, Spencer K, Anderson R, Cook EJ. Free beta chorionic gonadotropin: a cross reactivity study of two immunometric assays used in prenatal maternal serum screening for Down syndrome. Clin Chem (in press).
Non-echogenic nuchal oedema as a marker in trisomy 21
screening
SiR.—Dr Schulte-Vallentin and Dr Schindler (April 25, p 1053) report the detection of trisomy 21 early in pregnancy through ultrasonographic demonstration of a prominent non-echogenic nuchal oedema, measuring about 4-7 mm in diameter. In a prospective study, started in 1990, 1430 patients were referred to