Alexandra Dumitrescu
Section of Endocrinology, Diabetes and Metabolism
Assistant Professor of Medicine
Referring Physician Access Line: 1-877-DOM-2730

Training

DegreeYearInstitutionArea
BS1992High School Alexandru Lahovari, Rimnicu Vilcea, Romania 
MD1998University of Medicine and Pharmacy Carol DavilaMedicine and Pharmacy
PhD2005University of ChicagoHuman Genetics
Residency2009University of ChicagoInternal Medicine
Fellowship2012University of ChicagoEndocrinology

Academic Interests

Dr. Dumitrescu’s research is focused on the study of the pathophysiology of inherited defects affecting the thyroid function, in particular those involving transmembrane thyroid hormone transport and intracellular thyroid hormone metabolism. One of the defects she studies is that of the X-linked gene MCT8, a transmembrane transporter of thyroid hormone. Its deficiency results in severe psychomotor and development delay in males, also known as Allan Herndon Dudley syndrome. Among known inherited disorders of the thyroid axis in humans, this is the first involving thyroid hormone transport into cells. Dr. Dumitrescu has generated an Mct8 knockout mouse model. Extensive in vivo and in vitro work on this mouse model continues to uncover the underlying mechanisms for this complex defect.Another novel thyroid defect she studies is that caused by mutations in selenocysteine incorporation sequence binding protein 2 (SBP2) and represents the first defect in a component of the selenoprotein synthesis machinery. This deficiency has consequence on growth and thyroid function at young age, causes decreased fertility in males and is expected to result in increased cancer susceptibility in both genders with age. Severe SBP2 gene mutations present additional features, such as congenital myopathy, developmental delay, sensorineural hearing loss and complex immune deficits, thus reflecting multiple selenoprotein deficiencies. Dr. Dumitrescu's current studies address the need for an in vivo model to further understand the pathophysiology of this new genetic defect, by generating mouse models with Sbp2 deficiency. Initial investigations will uncover the underlying mechanisms for the characteristic thyroid phenotype, infertility, growth delay and myopathy. The study of the aging animals will allow close monitoring for manifestations later in life, and other presumed phenotypes, including cancer, neurodegenerative disorders and immune dysfunction.


Clinical Interests

Endocrinology,thyroidology,inherited thyroid diseases,genetic syndromes


Representative Publications

  1. Dumitrescu AM, Liao XH, Best TB, Brockmann K, Refetoff S. A novel syndrome combining thyroid and neurological abnormalities is associated with mutations in a monocarboxylate transporter gene. Am J Hum Genet. 2004 Jan;74(1):168-75. PMID: 14661163
  2. Dumitrescu AM, Liao XH, Abdullah MS, Lado-Abeal J, Majed FA, Moeller LC, Boran G, Schomburg L, Weiss RE, Refetoff S. Mutations in SECISBP2 result in abnormal thyroid hormone metabolism. Nature Genetics. 2005 Nov;37(11):1247-52. PMID: 16228000
  3. Dumitrescu AM, Liao XH, Weiss RE, Millen K, Refetoff S. Tissue-specific thyroid hormone deprivation and excess in monocarboxylate transporter (Mct) 8-deficient mice. Endocrinology. 2006 Sep;147(9):4036-43. PMID: 16709608
  4. Di Cosmo C, Liao XH, Dumitrescu AM, Philp NJ, Weiss RE, Refetoff S. Mice deficient in MCT8 reveal a mechanism regulating thyroid hormone secretion. J Clin Invest. 2010 Sep 1;120(9):3377-88. PMID: 20679730
  5. Liao XH, Di Cosmo C, Dumitrescu AM, Hernandez A, Van Sande J, St Germain DL, Weiss RE, Galton VA, Refetoff S. Distinct roles of deiodinases on the phenotype of Mct8 defect: a comparison of eight different mouse genotypes. Endocrinology. 2011 Mar;152(3):1180-91. PMID: 21285310



More Information

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