P-039 Parthenogenetic chimeras may be the cause of the development of a case of 46, XX/46, XY chimeras complicated by severe oligozoospermia
Authors: Ikeda S , Koyama N , Kinoshita K , Miyoshi J , Masuda H , Kurahashi H 
Published: July 2024

Study question

How did the 46,XX/46,XY chimeric case of severe oligozoospermia arise?

Summary answer

DNA analysis suggested the possibility of monogenetic chimerism as a mechanism for the development of this case.

What is known already

Sex-chromosome discordant chimerism in humans(XX/XY chimerism)is a rare chromosomal abnormality. Although the first case was described in 1962, its incidence is still unknown. The XX/XY chimera manifests variable genital phenotypes. The XX/XY chimera is classified into subtypes; tetragametic chimeras, parthenogenetic chimeras, androgenetic chimeras and sesquizygotic twinning chimeras. Genotyping of XX/XY chimeras is important no only to clarify its developmental mechanism

but also for diagnosis and treatment. As a result, patients occasionally present with infertility. We present a case of a parthenogenetic chimera with a karyotype of XX/XY in relation to infertility.

Study design, size, duration

case research. We researched from July 2023 to December 2023.

Participants/materials, setting, methods

A 38-year-old man diagnosed with azoospermia by his previous physician presented to our clinic with primary infertility for 1 year and 6 months. At 28 years old, he presented with left testicular inflammation and subsequent atrophy. He has no sexual problems. He has an older sister and a younger sister, both married with children.

Main results and the role of chance

Physical findings: BH 163 cm, BW 53 kg, BMI 19.95, external genitalia: male. Semen analysis: severe oligozoospermia: mostly immobile sperm with some sperm moving slightly in situ. Morphology (Kurger strict criteria): no abnormal sperm morphology. Left testicular hypoplasia: USG: 12 ml right testis, 1 ml left, no other problems. Abdominal MRI: no abnormalities in the kidney to the bladder. No uterus or ovaries. Prostate and seminal vesicles normal; AMH 3.34ng/ml (0.77-14.5) Testosterone 6.55ng/ml (1.95-7.63), DHEA-S 199 μg/dl(106-464),LH 6.2, FSH 7.5, E2 32.5, PRL 12.43, blood type A, Rh+, RH-Hr:CcDee, HLA-A, B, C, DR: all undetermined, Y chromosome SRY (FISH): SRY signal numbers 0 and 1 were observed. Chromosome analysis (G band): 46, XX[22]/46, XY[8].

SNP microarray chromosome examination: presumptive parthenogenic chimerism

Treatment: His wife underwent oocyte pick up and intracytoplasmic sperm injection(ICSI) was performed using his frozen sperm. One blastocyst was frozen, but one frozen-thawed blastocyst transfer during an HRT cycle failed to result in pregnancy. The use of assisted reproductive technology(ART) is currently ongoing.

Limitations, reasons for caution

DNA analysis of both parents was necessary to determine the cause of the problem, but the patient refused to have her parents tested.

Wider implications of the findings

By accumulating and studying a large number of cases like this one, it may be possible to correctly treat patients with 46, XX/46, XY chimeric infertility.

Trial registration number

not applicable