(27) A Case Study of a Female Infant with Paternally Acquired Triploidy (68, XX)

Background: Triploidy is a rare chromosomal disorder characterized by the presence of an additional haploid set of chromosomes, typically resulting in a total of 69 chromosomes. This condition may arise from dispermy or meiotic errors, with either maternal or paternal origin of the extra haploid set.

Objectives: We present the case of a prematurely born female infant whose clinical course was notable for meningomyelocele, syndactyly, feeding intolerance, and intrauterine growth restriction and was ultimately diagnosed with paternally derived hypotriploidy (68, XX). We provide a comprehensive overview of her clinical trajectory for her 40 days of life and compare her clinical outcomes to prior cases of 68, XX and cases of true triploidy.

Design/Methods: The patient’s presentation was summarized through a chart review of her clinical course at Cincinnati Children’s Hospital Medical Center. Additionally, a literature review was conducted using PubMed with the following search terms: ‘Hypotriploidy’, ‘Triploidy’, and ‘X-inactivation’.

Results: We explored several hypotheses to account for the distinct phenotypic features observed in this case, which diverge from the typical presentation of previously reported cases of triploidy. These include the paternal origin of the extra chromosome set, mechanisms of X-inactivation, the minimal pathogenic impact of an additional X chromosome, and the possibility that reduced global gene expression and protein load contributed to a comparatively milder phenotype.

Conclusions: We report the case of a prematurely born female infant diagnosed with paternally derived hypotriploidy (68,XX), who presented with multiple congenital anomalies and survived for 40 days—longer than typically seen in triploidy. To explain her atypical phenotype, we considered several contributing factors. This case underscores the importance of timely and accurate genetic diagnosis, as the absence of a confirmed diagnosis early in her course may have led to more aggressive interventions and prolonged care. By contributing to the limited body of literature on 68,XX triploidy, particularly with paternal origin, this report may help inform clinical expectations and support future families in making more informed decisions following a similar diagnosis.