Occurrence of Klinefelter Syndrome Mosaic 45,X/46,XY/47,XXY/48,XXYY/48,XXXY and Primary Hyperparathyroidism

• Published in: AACE clinical case reports Vol. 7; no. 5; pp. 293 - 298
• Main Authors: Lam-Chung, César Ernesto, Rodríguez, Larissa López, Kato, Yayoi Segura, Jiménez González, Iván Josué, Mena-Hernández, Lourdes, Rivera-Juárez, Renata, Almeda-Valdes, Paloma, Vázquez, Jazmín Arteaga
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-09-2021; American Association of Clinical Endocrinology; Elsevier
• Subjects: Case Report; hyperparathyroidism; Klinefelter syndrome; mosaicism; nephrolithiasis; Klinefelter syndrome; PTH; mosaicism; nephrolithiasis; KS; PHPT; hyperparathyroidism; LH; LH, luteinizing hormone; KS, Klinefelter syndrome; PHPT, primary hyperparathyroidism; PTH, parathyroid hormone
• ISSN: 2376-0605; 2376-0605
• DOI: 10.1016/j.aace.2021.03.001

The presence of primary hyperparathyroidism (PHPT) and Klinefelter syndrome (KS) is rare, and its association with KS mosaicism is even rarer. We report an unusual combination of these entities with a mild phenotype of KS.
The patient was a 44-year-old male with a history of PHPT who had recurrent urolithiasis despite being treated with a successful parathyroidectomy. On examination, he had axillary hair growth, bilateral gynecomastia, a large port-wine stain at the right hemithorax and upper right limb, and genitalia and pubic hair corresponding to Tanner IV classification with small, normal consistency testicles.
Laboratory findings were unremarkable except for a slightly elevated luteinizing hormone, which was normal on repeat testing. Because of the picture of unexplained gynecomastia, laboratory findings, and low-volume testis, a diagnosis of KS was considered. Chromosomal analysis revealed a rare 45,X/46,XY/47,XXY/48,XXYY/48,XXXY KS mosaic.
KS phenotypes are largely variable, and their association with PHPT remains to be elucidated.