Abstract
In 20-30% cases of infertility, a primary defect is found in the male partner and contribute to 50% of patients overall. Studies have shown that the prevalence of both numerical and structural chromosomal abnormalities is increased in such men. A few genes have been implicated in sex development during gonadal and functional differentiation, where the maintenance of the somatic sex as either male or female is achieved by the suppression of the alternate route. One such entity in the vast group of male infertility etiologies is the de la Chapelle syndrome or 46, XX testicular disorder of sex differentiation (DSD), which is a rare disorder characterized by discordance between the male phenotype and the female karyotype. This syndrome's exact molecular and genetic basis is yet to be described in full potential. Due to the rare diagnosis of such cases, we report this case of infertile male diagnosed as SRY-positive 46, XX testicular DSD, aiming to add to the previously reported cases in the literature.
Keywords: Disorder of sex differentiation; Primary male infertility; de la Chapelle syndrome; 46, XX male
Introduction
46, XX testicular disorder of sex differentiation (DSD), or de la Chapelle syndrome, is a DSD in which the gonadal sex (i.e. male phenotype) does not match the chromosomal sex (i.e. 46,XX). Literature records of the first such case return to 1964 when Albert de la Chapelle first described it, and until now, few cases have been reported.1 The incidence is 1:20,000 to 25,000 male infants and is further categorized into SRY-positive or SRY-negative individuals, depending on the presence or absence of the sex-determining region Y gene (SRY).2,3 The clinical presentations of these patients are variable. Patients may present in early life with undescended testes, micropenis, hypospadias, and the presence of residual embryonic remnants of the Müllerian duct structures. Later, patients may present with failed puberty or infertility with preserved male internal and external genitalia.4 The diagnosis of DSD involves a multi-disciplinary approach and the use of different upcoming molecular techniques.
Case report
A 29-year-old healthy male patient presented to our center with the inability to father a child after 3 years of marriage and 1 year of unprotected sexual intercourse. The patient, being the youngest, was born into a family of six children, two males, and four females. He had a normal childhood with no developmental milestone delay, no history of testicular injury, or delayed puberty. He shows a normal male phenotype with no structural defects in the penis and testis. On anthropometry, the patient's height is 169 cm and weighs 94 kg. His BMI, as calculated, comes out as 32.9. His axillary and pubic hair show normal development. He had no gynecomastia. Other system examinations revealed no abnormality clinically.
His seminal fluid analysis showed azoospermia. His hormonal study showed:
Luteinizing hormone (LH) – 13.43 mIU/ml (normal range 1.1–7 mIU/ml), follicular stimulating hormone (FSH) – 11.53 mIU/ml (normal range 1.7–12 mIU/ml), prolactin 5.76 ng/ml (3–25 ng/ml), and testosterone −3.17 ng/ml (normal range 3–16 ng/ml). The thyroid profile was within normal limits. An ultrasound scan of the abdomen and pelvis showed no gross abnormalities. An ultrasound scan of the testis showed the presence of grade II varicocele on both sides with normal testis and epididymis.
Karyotyping performed on peripheral blood mononuclear cells showed 46,XX chromosomal complement and fluorescence in situ hybridization (FISH) test performed on interphase cells with centromeric XY probe report showed two hybridization signals (SG) for the X chromosome and no signal (SO) for the Y chromosome, consistent with karyotype analysis (Fig. 1). Metaphase FISH performed with SRY FISH probe showed SRY gene is positive on chromosome X and therefore suggesting the presence of cryptic t(X; Y).
Fig. 1.
A) Karyogram showing 46, XX chromosomal complement. (B) FISH analysis with centromeric XY probe on interphase cells showing two hybridization signals (SG) for the X chromosome and no signal (SO) for the Y chromosome. (C) Chromosomal microarray analysis showed a loss (896 Kb) involving chromosome X at cytoregion Xp22.33, indicating monosomy for this region. There is also the presence of bands (3.7 Mb) and (2.6 Mb), which co-localizes with cytoregion Yp11.31p11.2 and Yp11.2, respectively. (D) Metaphase FISH performed with SRY FISH probe showed SRY gene is positive on chromosome X suggesting cryptic t(X; Y).
The chromosomal microarray analysis showed a loss (896 Kb) involving chromosome X at cytoregion Xp22.33, indicating monosomy for this region. This segment also includes the ARSL gene. There is also the presence of bands (3.7 Mb) and (2.6 Mb), which co-localizes with cytoregion Yp11.31p11.2 and Yp11.2, respectively. This segment also includes the SRY gene. Translocation of a segment of the Y chromosome containing the SRY gene (480,000; Yp11.3) to the X chromosome causes 46, XX sex reversal and 46, XX true hermaphroditism. Homozygosity for contiguous SNP alleles was also detected on chromosome 3. Based on the patient's complete hormonal and cytogenomic workup, he was finally diagnosed with a case of de la Chapelle Syndrome.
The couple was counseled adequately in explicit terms to make them aware of the condition and the options to achieve parenthood. After much deliberation, the couple opted for donor sperm. The couple underwent ovulation induction and intrauterine insemination (IUI) with donor sperms at our center and was conceived in the first cycle. Pregnancy was uneventful and delivered at term healthy baby. Patients informed consent was obtained for inclusion in the study.
Discussion
Disorder of sex differentiation (DSD) encompasses a comprehensive group of disorders presenting inborn dissonance between sex chromosomal complement and phenotypic display.5 DSDs are categorized based on the variations in the levels of gender description by various terminologies according to genetic makeup, chromosomal configuration, type of gonad present, hormonal level, appearance of external genitalia, and the presence of secondary characters, as well as legal validation and psychological characteristics. However, in the field of clinical genetics, the management of patients is performed as per the classification proposed by the Paediatric Endocrinology Society Lawson Wilkins and the European Society of Paediatric Endocrinology. Based on karyotype, the classification incorporates the following categories: (1) sex chromosome DSD, (2) 46,XX DSD and (3) 46,XY DSD.6,7 The testicular DSD or de la Chapelle syndrome is a rare genetically heterogenous group of gender dysplasia under the subgroup of 46, XX DSD. Differential diagnosis of 46,XX testicular DSD is ovotesticular DSD.8 Out of four proposed mechanisms for an etiological explanation, the translocation of Y sequences incorporating SRY gene to an X chromosome or any autosome is demonstrated most frequently (90%). In this case, metaphase FISH confirmed SRY gene got translocated on the X chromosome. SRY gene is assumed to be responsible for the suppression of an inhibitor of male gonadal development. Nevertheless, on further deliberation, it was found that syndromic individuals may or may not possess an SRY gene. However, 46, XX testicular DSD is usually a sporadic disorder, but few familial cases have also been recognized, suggesting autosomal recessive inheritance in those cases. Patients in the SRY-positive cases, which is the predominant group, usually present in adolescence or early adulthood with complaints of shorter height, gynecomastia, small testis, and azoospermia. During the embryonal development in most of the mammalian species, transient SRY gene expression is postulated to trigger a downstream of cascade leading to the generation of testis from the gonadal ridge. In the present case, the patient presented with male phenotype due to the presence of functional SRY gene. On the other hand, azoospermia leading to infertility is ascribed to the absence of azoospermia factor region (AZF), which is located on the long arm of the Y chromosome.9 Hormonal evaluation of the patient showed low normal testosterone level, normal prolactin level, and normal thyroid function test with high normal FSH and elevated LH level suggesting features of hypergonadotropic hypogonadism consistent with primary testicular failure. To understand the genetic biology of the disease and for comprehensive management, a complete cytogenomic workup is recommended in all 46, XX testicular DSD cases. These investigations also help to infer that phenotype heterogeneity seen in these cases is due to the case-wise variation in the quantity of retained Y chromosome-specific material.
In SRY-negative cases (representing around 10% of cases), it is postulated that the male phenotypic expression results due to either overexpression of downstream pro-testis genes (i.e. SOX-3, SOX-9, and SOX-10) or diminished expression of anti-testis genes, such as DAX-1, WNT4, and RSPO1.10
Conclusion
de la Chapelle syndrome can significantly influence individuals' personal, social, and married lives. Though early diagnosis would still not allow the cure of this condition, the couple can be counseled for opting for donor sperm to mitigate the distress. Our study emphasized the recommendation of performing cytogenetic evaluation in all phenotypically normal males with azoospermia so that we should not miss out on the diagnosis of this rare but important cause of primary male infertility.
Patients/ Guardians/ Participants consent
Patients informed consent was obtained.
Ethical clearance
Not applicable.
Source of support
Nil.
Disclosure of competing interest
The authors have none to declare.
Acknowledgement
The authors acknowledge the contribution of Aradhana Dwivedi, Medical Geneticist, Army Hospital (R&R), Delhi Cantt, India.
References
- 1.Chapelle A., Hortling H., Niemi M., Wennström J. XX sex chromosomes in a human male. Acta Med Scand. 2009 Apr 24;175:25–38. doi: 10.1111/j.0954-6820.1964.tb04630.x. [DOI] [PubMed] [Google Scholar]
- 2.Abbas N., Toublanc J., Boucekkine C., et al. A possible common origin of ?Y-negative? human XX males and XX true hermaphrodites. Hum Genet. 1990 Mar;84(4) doi: 10.1007/BF00196234. [DOI] [PubMed] [Google Scholar]
- 3.Ahmad A., Siddiqui M.A., Goyal A., Wangnoo S.K. Is 46XX karyotype always a female? Case Reports. 2012 Jul 18;2012 doi: 10.1136/bcr-2012-006223. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Alkhzouz C., Bucerzan S., Miclaus M., Mirea A.M., Miclea D. 46, XX DSD: developmental, clinical and genetic aspects. Diagnostics. 2021 Jul 30;11(8):1379. doi: 10.3390/diagnostics11081379. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Ashfaq S., Siddiqui A., Shafiq W., Azmat U. A rare presentation of disorder of sex development. Cureus. 2021 Jan;13(1) doi: 10.7759/cureus.12782. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Hughes I.A., Houk C., Ahmed S.F., Lee P.A. LWPES Consensus Group, ESPE Consensus Group. Consensus statement on management of intersex disorders. Arch Dis Child. 2006 Jul;91(7):554–563. doi: 10.1136/adc.2006.098319. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Cools M., Nordenström A., Robeva R., et al. Caring for individuals with a difference of sex development (DSD): a Consensus Statement. Nat Rev Endocrinol. 2018 Jul 16;14(7):415–429. doi: 10.1038/s41574-018-0010-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Özdemir M., Kavak R.P., Yalcinkaya I., Guresci K. Ovotesticular disorder of sex development: an unusual presentation. J Clin Imaging Sci. 2019 Jul 12;9:34. doi: 10.25259/JCIS_45_2019. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Koh E., Sin H.S., Fukushima M., Namiki M. Azoospermia factor and male infertility. Reprod Med Biol. 2010 Sep;9(3):129–137. doi: 10.1007/s12522-010-0055-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Grinspon R.P., Rey R.A. Disorders of sex development with testicular differentiation in & SRY-negative 46,XX individuals: clinical and genetic aspects. Sex Dev. 2016;10(1):1–11. doi: 10.1159/000445088. [DOI] [PubMed] [Google Scholar]