Diagnosis and Treatment > Signs and Symptoms
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Summary
A 40-year-old man with achondroplasia presented with symptoms of hypogonadism, low libido and gynaecomastia. He was found to have hypergonadotropic hypogonadism, and karyotype and fluorescent in situ hybridisation analysis showed SRY-positive 46, XX disorder of sex development (DSD). He was tested to have the common activating mutation of the FGFR3 gene implicated in achondroplasia, indicating that he had the two rare conditions independently, with an extremely low incidence of 1 in 400 million. This, to the best of our knowledge, is the first report of an individual having these two rare conditions concurrently. This case highlights that individuals with achondroplasia should have normal sexual development, and in those presenting with incomplete sexual maturation or symptoms of hypogonadism should prompt further evaluation. We also propose a plausible link between achondroplasia and 46, XX DSD through the intricate interactions between the SRY, SOX9 and FGFR9 gene pathways.
Learning points:
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The SOX9 and FGF9 genes, which are upregulated by the SRY gene, are important in both sex determination in the embryo, as well as endochondral bone growth.
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Patients with achondroplasia should have normal sexual development and function in the absence of other confounding factors.
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Patients with achondroplasia who present with symptoms and signs of abnormal sexual development and/or hypogonadism should be appropriately investigated for other causes.
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Search for other papers by Takashi Akamizu in
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Summary
Myotonic dystrophy type 1 (DM1) is an autosomal dominant multisystem disease affecting muscles, the eyes and the endocrine organs. Diabetes mellitus and primary hypogonadism are endocrine manifestations typically seen in patients with DM1. Abnormalities of hypothalamic–pituitary–adrenal (HPA) axis have also been reported in some DM1 patients. We present a case of DM1 with a rare combination of multiple endocrinopathies; diabetes mellitus, a combined form of primary and secondary hypogonadism, and dysfunction of the HPA axis. In the present case, diabetes mellitus was characterized by severe insulin resistance with hyperinsulinemia. Glycemic control improved after modification of insulin sensitizers, such as metformin and pioglitazone. Hypogonadism was treated with testosterone replacement therapy. Notably, body composition analysis revealed increase in muscle mass and decrease in fat mass in our patient. This implies that manifestations of hypogonadism could be hidden by symptoms of myotonic dystrophy. Our patient had no symptoms associated with adrenal deficiency, so adrenal dysfunction was carefully followed up without hydrocortisone replacement therapy. In this report, we highlight the necessity for evaluation and treatment of multiple endocrinopathies in patients with DM1.
Learning points:
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DM1 patients could be affected by a variety of multiple endocrinopathies.
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Our patients with DM1 presented rare combinations of multiple endocrinopathies; diabetes mellitus, combined form of primary and secondary hypogonadism and dysfunction of HPA axis.
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Testosterone treatment of hypogonadism in patients with DM1 could improve body composition.
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The patients with DM1 should be assessed endocrine functions and treated depending on the degree of each endocrine dysfunction.
