Faculty Bibliography

OBJECTIVE: To report the case of a man who presented with profoundly elevated parathyroid hormone levels in the setting of hypercalcemia, a palpable neck mass, renal disease, and metabolic bone disease. METHODS: We describe the clinical, imaging, and laboratory findings of the patient, including results from genetic testing of the CDC73 gene (HRPT2), and review the relevant literature. RESULTS: A 28-year-old man with a history of childhood abdominal neuroblastoma treated with chemotherapy and field radiation therapy presented with a 2-week history of persistent left scapular pain and swelling. He had a freely mobile, 1-cm, homogeneous, nontender, firm nodule in the right anterior neck. Parathyroid hormone concentration at hospital admission was 1127 pg/mL. Single-photon emission computed tomography after intravenous administration of technetium Tc 99m-labeled sestamibi revealed an intense focus of abnormal radiotracer uptake on early and delayed images in the right anterior inferior neck. Computed tomography imaging of the chest and neck revealed a 1.9-cm, smooth, calcified nodule posterior to the right lobe of the thyroid gland and diffusely osteopenic bones with trabecular resorption and numerous scattered lucent regions consistent with brown tumors. On bilateral neck exploration, a right inferior parathyroid mass and the left superior parathyroid gland were excised. The remaining 2 parathyroid glands were identified intraoperatively and appeared normal. Genetic testing of the CDC73 gene did not detect germline mutations. CONCLUSIONS: This case highlights the overlap between the clinical findings seen in primary hyperparathyroidism and parathyroid carcinoma. Enhanced understanding of the genetic and molecular bases of primary hyperparathyroidism and parathyroid carcinoma should aid in the diagnosis of these diseases and the care of affected patients.

OBJECTIVE: Anorexia nervosa is associated with a high prevalence of psychiatric comorbidities, including anxiety and depression, and with endocrine dysfunction, including relative androgen deficiency compared with healthy young women. Because androgens are known to affect mood and behavior, we hypothesized that low endogenous androgen production in anorexia nervosa would predict anxiety and depression severity. METHOD: Serum androgen levels and severity of depression (Hamilton Rating Scale for Depression) and anxiety (Hamilton Rating Scale for Anxiety) were measured in 43 community-dwelling women with DSM-IV-defined anorexia nervosa from May 2004 to July 2006. RESULTS: Strong inverse associations were observed between both total and free testosterone and anxiety and depression severity, independent of weight. Free testosterone was also inversely associated with 4 eating-disordered thinking and behavior subscales of the Eating Disorder Inventory 2 (EDI-2). Mean free testosterone blood levels were lower in women with clinically significant anxiety and in women with clinically significant depression, compared with those without. In stepwise regression models, free testosterone was an important predictor of anxiety and depression severity. EDI-2 ineffectiveness, perfectionism, interpersonal distress, and social insecurity scores were also inversely associated with androgen levels, independent of weight. CONCLUSIONS: Our data suggest that low androgen levels may contribute to anxiety, depression, and eating-disordered thinking and behavior in women with anorexia nervosa and form the basis for future studies to investigate the effectiveness of androgen replacement therapy. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov identifier NCT00089843.

CONTEXT: Anorexia nervosa and normal-weight hypothalamic amenorrhea are characterized by hypogonadism and hypercortisolemia. However, it is not known whether these endocrine abnormalities result in reductions in adrenal and/ or ovarian androgens or androgen precursors in such women, nor is it known whether relative androgen deficiency contributes to abnormalities in bone density and body composition in this population. OBJECTIVE: Our objective was to determine whether endogenous androgen and dehydroepiandrosterone sulfate (DHEAS) levels: 1) are reduced in women with anorexia nervosa and normal-weight hypothalamic amenorrhea, 2) are reduced further by oral contraceptives in women with anorexia nervosa, and 3) are predictors of weight, body composition, or bone density in such women. DESIGN AND SETTING: We conducted a cross-sectional study at a general clinical research center. STUDY PARTICIPANTS: A total of 217 women were studied: 137 women with anorexia nervosa not receiving oral contraceptives, 32 women with anorexia nervosa receiving oral contraceptives, 21 normal-weight women with hypothalamic amenorrhea, and 27 healthy eumenorrheic controls. MAIN OUTCOME MEASURES: Testosterone, free testosterone, DHEAS, bone density, fat-free mass, and fat mass were assessed. RESULTS: Endogenous total and free testosterone, but not DHEAS, were lower in women with anorexia nervosa than in controls. More marked reductions in both free testosterone and DHEAS were observed in women with anorexia nervosa receiving oral contraceptives. In contrast, normal-weight women with hypothalamic amenorrhea had normal androgen and DHEAS levels. Lower free testosterone, total testosterone, and DHEAS levels predicted lower bone density at most skeletal sites measured, and free testosterone was positively associated with fat-free mass. CONCLUSIONS: Androgen levels are low, appear to be even further reduced by oral contraceptive use, and are predictors of bone density and fat-free mass in women with anorexia nervosa. Interventional studies are needed to confirm these findings and determine whether oral contraceptive use, mediated by reductions in endogenous androgen levels, is deleterious to skeletal health in such women.

Sensory axons extend from the chick olfactory epithelium to the telencephalon well before the maturation of their target, the olfactory bulb. During a waiting period of several days, olfactory axons arrive and accumulate outside the CNS while the bulb differentiates beneath them. Semephorin-3A is expressed in the tel-encephalon during this period and has been proposed to prevent their entry into the CNS. We show that the misexpression of a dominant-negative neuropilin-1 that blocks SEMA-3A-mediated signaling in olfactory sensory axons induces many of them to enter the tel-encephalon prematurely and to overshoot the olfactory bulb. These results suggest that chemorepellents can prevent the premature innervation of immature targets.

We examined the cellular localization of nine different connexin32 (Cx32) mutants associated with X-linked Charcot-Marie-Tooth disease (CMTX) in communication-incompetent mammalian cells. Cx32 mRNA was made, but little or no protein was detected in one class of mutants. In another class of mutants, Cx32 protein was detectable in the cytoplasm and at the cell surface, where it appeared as plaques and punctate staining. Cx32 immunoreactivity in a third class of mutants was restricted to the cytoplasm, where it often colocalized with the Golgi apparatus. Our studies suggest that CMTX mutations have a predominant effect on the trafficking of Cx32 protein, resulting in a potentially toxic cytoplasmic accumulation of Cx32 in these cells. These results and evidence of cytoplasmic accumulation of other mutated myelin proteins suggest that diseases affecting myelinating cells may share a common pathophysiology.