Chromosome 15 aneuploidy in the sperm and conceptus of a sibling with variable familial expression of round-headed sperm syndrome

Chromosome 15 aneuploidy in the sperm and conceptus of a sibling with variable familial expression of round-headed sperm syndrome

FERTILITY AND STERILITY威 VOL. 76, NO. 6, DECEMBER 2001 Copyright ©2001 American Society for Reproductive Medicine Published by Elsevier Science Inc. P...

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FERTILITY AND STERILITY威 VOL. 76, NO. 6, DECEMBER 2001 Copyright ©2001 American Society for Reproductive Medicine Published by Elsevier Science Inc. Printed on acid-free paper in U.S.A.

Chromosome 15 aneuploidy in the sperm and conceptus of a sibling with variable familial expression of roundheaded sperm syndrome Douglas T. Carrell, Ph.D.,a,b,c Aaron L. Wilcox, B.S.,a Laurence C. Udoff, M.D.,b Cindy Thorp, M.S.,c and Bruce Campbell, M.D.c University of Utah School of Medicine, Salt Lake City, Utah, and Abbott Northwestern Hospital, Minneapolis, Minnesota

Received April 19, 2001; revised and accepted June 13, 2001. Reprint requests: Douglas T. Carrell, Ph.D., Division of Urology, Room 3B208, University of Utah School of Medicine, 50 North Medical Dr., Salt Lake City, Utah 84132 (FAX: 801-5816127). a Division of Urology, University of Utah School of Medicine. b Department of Obstetrics and Gynecology, University of Utah School of Medicine. c Center for Reproductive Medicine, Abbott Northwestern Hospital. 0015-0282/01/$20.00 PII S0015-0282(01)02904-1

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Objective: To characterize rates of chromosome aneuploidy in sperm from three siblings, one of whom had an IVF/ICSI conceptus with trisomy 15. Design: Blind evaluation of the sperm chromosome aneuploidy rates, semen quality, and sperm ultrastructure. Setting: IVF clinic and university-based andrology research laboratory. Patient(s): Three brothers, two of whom underwent infertility evaluation and therapy. Main Outcome Measure(s): Semen from three siblings was coded and blindly evaluated for standard World Health Organization semen quality variables and sperm ultrastructure. Sperm were decondensed and hybridized with fluorescent probes specific for chromosomes X, Y, 13, 15, 18, and 21, then evaluated microscopically to determine the aneuploidy rate for those chromosomes. Result(s): Two siblings had increased round-headed morphology on standard morphology evaluation, which was confirmed using electron microscopy. The sperm aneuploidy rate was significantly increased for chromosome 15 in sibling 1, the father of a conceptus with trisomy 15. Aneuploidy rates were also slightly increased for chromosomes X, Y, and 18 in sibling 1. Conclusion(s): This is the second report of increased sperm chromosome aneuploidy in infertile patients with round-headed sperm. Although ICSI is successful in treating this syndrome, the risk for aneuploidy of the conceptus may be increased. Other studies have reported an increased incidence of sperm chromosome aneuploidy in some infertile patients, but this is the first report of aneuploidy in both the sperm and conceptus of a patient undergoing IVF/ICSI. (Fertil Steril威 2001;76:1258 – 60. ©2001 by American Society for Reproductive Medicine.) Key Words: Sperm aneuploidy, round-headed sperm, morphology, chromosome, spontaneous abortion

Round-headed sperm syndrome is a variably expressed disorder responsible for a small percentage (⬍1%) of male infertility (1). Type 1 round-headed sperm syndrome is characterized by universally round-headed sperm without acrosomes. Type 2 round-headed sperm syndrome is characterized by the presence of some sperm with other types of morphology and some sperm with acrosomes. Both type 1 and type 2 syndromes are often associated with other defects of sperm function. Because of the lack of the acrosome, round-headed sperm typically have severely diminished fertilization ability; however, pregnancies have been ob-

tained by IVF/ICSI (2). Increased sperm chromosome aneuploidy has been shown to occur in various types of male infertility. We previously reported on the variable expression of sperm defects, including sperm chromosome aneuploidy, in two siblings with round-headed sperm syndrome (3). We now report an elevated rate of aneuploidy for chromosome 15 in the sperm of a patient who underwent IVF/ ICSI resulting in spontaneous abortion of a conceptus with trisomy 15. Two brothers, one of whom was undergoing infertility therapy at another clinic, were also evaluated for semen quality and sperm chromosome aneuploidy.

TABLE 1 Semen quality and sperm chromosome aneuploidy rates in three siblings. Assay Sperm concentration (million/mL) Progressive motility (%) WHO normal morphology (%) Round-headed morphology (%) Viability (% viable) HOS (% reactive) Chromosome X aneuploidy (%) Chromosome Y aneuploidy (%) Chromosome 13 aneuploidy (%) Chromosome 15 aneuploidy (%) Chromosome 18 aneuploidy (%) Chromosome 21 aneuploidy (%)

Sibling 1

Sibling 2

Sibling 3

Normal range

81 28 7 76 46 58 0.46 0.52 0.40 4.03 0.74 0.40

103 54 0 70 62 68 0.58 0.60 0.32 0.58 0.74 0.14

94 76 72 2 72 68 0.28 0.28 0.32 1.18 0.56 0.22

⬎30 ⬎50 ⬎55 ⬍5 ⬎50 ⬎55 ⬍0.40 ⬍0.40 ⬍0.40 ⬍0.40 ⬍0.40 ⬍0.40

Note: WHO ⫽ World Health Organization. Carrell. Chromosome 15 aneuploidy in sperm and conceptus. Fertil Steril 2001.

CASE REPORT Because all studies were performed during routine clinical evaluation, institutional review board approval was not requested. A 28-year-old woman and her spouse underwent IVF/ICSI after initial evaluation for primary infertility, which included hysterosalpingography, day 3 endocrine evaluation, cervical culture, and physical examination of the woman. All results were within normal ranges. Her 31-yearold husband underwent standard semen analysis using World Health Organization criteria. Analysis revealed a decreased proportion of morphologically normal sperm (22%) and an increased proportion of round-headed sperm. Therefore, IVF/ICSI therapy was recommended. Ovarian stimulation was performed using standard GnRH agonist down-regulation, followed by gonadotropin stimulation (Fertinex; Serono, Norwell, MA). A peak estradiol level of 2,556 pg/mL was reached on day 10 of gonadotropin stimulation, and 12 follicles had a mean diameter of at least 15 mm. Transvaginal ultrasonography– guided follicle aspiration was performed 36 hours after hCG injection and yielded 11 oocytes. The oocytes were denuded 4 hours after retrieval, and 9 mature (metaphase 2) oocytes were inseminated by using standard ICSI techniques. Only 1 of the 9 oocytes underwent normal fertilization and resulted in an 8-cell embryo of good quality, which was transferred 72 hours after retrieval. The hCG level at 14 days after embryo transfer was 209 mIU/mL. The patient received standard progesterone supplementation after embryo transfer. The pregnancy spontaneously aborted at 9 weeks. Conceptus tissue was identified by the pathologist and sent for cytogenetic analysis. Twenty cells were analyzed, and a diagnosis of female karyotype with trisomy 15 (47,XX, ⫹15) was established. Karyotyping of both parents was normal. FERTILITY & STERILITY威

Because we previously observed aneuploidy in a patient with round-headed sperm, semen was collected from the patient for sperm chromosome analysis. Two siblings of the patient, one of whom had previously undergone infertility evaluation at another laboratory, requested evaluation of their sperm. Sperm from all three brothers was coded and blindly evaluated for standard semen quality variables and ultrastructure. Sperm were decondensed and hybridized with fluorescent probes specific for chromosomes X, Y, 13, 15, 18, and 21 (Vysis, Downers Grove, IL). At least 5,000 sperm were evaluated for each probe. Semen quality data and sperm aneuploidy rates for the three siblings are shown in Table 1. Sibling 1, the father of the conceptus with trisomy 15, had 7% normal morphology on light microscopy according to World Health Organization criteria, but all sperm observed under the electron microscope lacked a normal acrosome. Sibling 1 had a significant increase of aneuploidy for chromosome 15 (4.0%) and slight increases in chromosomes X, Y, and 18 (normal control values, ⬍0.40%). Sibling 2, the second sibling with a history of infertility, also had sperm with severely diminished morphology but had no marked increase in sperm chromosome aneuploidy. Sibling 3, who had a history of normal fertility, had normal semen quality and sperm ultrastructure. Of note, sibling 3 had an increase of aneuploidy for chromosome 15, although not as severe as sibling 1.

DISCUSSION Due to the low rate of sperm chromosome aneuploidy in normal men, determination of abnormal aneuploidy requires that large numbers of sperm be analyzed and strict quality control measures be used. Previous reports have documented increased sperm chromosome aneuploidy associated with severe male factor infertility (4). However, alterations in the 1259

aneuploidy rate are usually small and seldom exceed 5%. Therefore, the clinical significance of the increased aneuploidy rate has been questionable. This case report is the first documentation of an increased aneuploidy rate for a specific chromosome and aneuploidy of the same chromosome in a resulting conceptus. The case demonstrates the possible relationship between increased gamete aneuploidy and aneuploidy of the conceptus.

chromosomes have been analyzed. It may be possible that aneuploidy for other chromosomes is increased.

This is the second report of increased chromosome aneuploidy in a patient with round-headed sperm syndrome. Of note, in both reports, a sibling also had round-headed sperm syndrome but no associated increase in aneuploidy rate. Increased sperm chromosome aneuploidy appears to be a common feature of round-headed sperm syndrome, but further evaluation of other patients with this syndrome is needed to determine the frequency and severity of the problem. Studies have been limited by the fact that only selected

1. Singh G. Ultrastructural features of round-headed human spermatozoa. Int J Fertil 1992;37:99 –102. 2. Liu J, Nagy Z, Joris H, Tournaye H, Devroey P, Van Steirteghem A. Successful fertilization and establishment of pregnancies after intracytoplasmic sperm injection in patients with globozoospermia. Hum Reprod 1995;10:626 –9. 3. Carrell DT, Emery BR, Liu L. Characterization of aneuploidy rates, protamine levels, ultrastructure, and functional ability of round-headed sperm from two siblings and implications for intracytoplasmic sperm injection. Fertil Steril 1999;3:511–16. 4. Pfeffer J, Pang MG, Hoegerman SF, Osgood CJ, Stacey MW, Mayer J, et al. Aneuploidy frequencies in semen fractions from ten oligoasthenoteratozoospermic patients donating sperm for intracytoplasmic sperm injection. Fertil Steril 1999;72:472– 8.

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Our data indicate that although round-headed sperm syndrome can be successfully treated with IVF/ICSI, the chromosomal status of the sperm may warrant caution. Aneuploidy of some chromosomes may have more severe clinical consequence than others, but all may result in lower pregnancy rates. References

Chromosome 15 aneuploidy in the sperm and conceptus

Vol. 76, No. 6, December 2001