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Clemens Bergwitz, MD

Associate Professor of Medicine (Endocrinology)
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Associate Professor of Medicine (Endocrinology)

Biography

Clemens W.H. Bergwitz, MD, is an endocrinologist and Associate Professor of Medicine. In 2006, he identified the genetic defect underlying the childhood disorder Hereditary Hypophosphatemic Rickets with Hypercalciuria (HHRH), and since then, he has developed a research focus on inborn errors of bone and mineral metabolism. He leads several clinical trials and his lab uses murine models of hypophosphatemia to understand better the responses of the musculoskeletal and renal systems to oral phosphate therapy. Using genome-wide RNAi screens, a more recent research interest is in trying to understand how human and other metazoan cells sense inorganic phosphate and to identify mammalian systems suitable to study identified hits. He also attends the Endocrine Consult Service at Yale New Haven Hospital and, as a member of the Yale Medical Group, sees outpatients with hypophosphatemic disorders, osteoporosis, primary hyperparathyroidism, hyperthyroidism, thyroid nodules, hypogonadism, adrenal, and general endocrine disorders.

Appointments

Education & Training

Fellowship
Massachusetts General Hospital (2006)
Residency
Massachusetts General Hospital (2003)
Fellowship
NICHD, NIH (2001)
Residency
Hannover Medical School (1999)
Research Fellowship
Massachusetts General Hospital and Harvard Medical School (1996)
MD
Hannover Medical School (1993)
BA
Wilhelm Gymnasium, Chemistry and Ancient Greek (1986)

Research

Overview

Genetic causes of hypophosphatemia

In 2006 we identified the genetic defect underlying the childhood disorder Hereditary Hypophosphatemic Rickets with Hypercalciuria (HHRH). HHRH is caused by mutations in NaPi-IIc, a renal sodium-phosphate co-transporter, which is important to conserve phosphate in the kidney and when lost leads to hypophosphatemia and rickets. Our research goal is now to study the role of NaPi-IIc in human phosphate homeostasis and to understand the phenotypic variability of patients suffering from HHRH. For this purpose we are currently using mammalian and Xenopus oocyte expression systems to study the functional properties of the identified human NaPi-IIc mutations in vitro. Plan for the near future is to establish mouse models to study the role of NaPi-IIc in the development of renal stones in vivo. We also established international collaborations to look for NaPi-IIc mutations in new patients suffering from HHRH both to establish their molecular diagnosis and to carefully study their symptoms to see whether only some or all patients are at risk for developing kidney stones. In addition to HHRH I serve as the principal investigator on clinical trials for serveral other genetic skeletal disorders, including X-linked hypophosphatemia, osteogenesis imperfecta and hypophosphatasia.

Metabolic and homeostatic effects of phosphate

A more recent research interest is in trying to understand how human and other metazoan cells sense inorganic phosphate to explain the effects of phosphate on cell metabolism (“metabolic” sensing), how phosphate feeds back to regulate the above hormonal systems (“homeostatic” sensing) and whether the “metabolic” and the “homeostatic” sensor use the same or different signal transduction cascades.

For this purpose we have performed a genome-wide Drosophila RNAi knockdown in collaboration with Stephanie Mohr, Liz Perkins and Norbert Perrimon, Harvard Medical School using phosphate-induced activation of MAPK (in vitro). The identified 103 genes, including 84 phosphate-specific genes are currently evaluated in life flies with assays for dietary phosphate toxicity, hemolymph phosphate and life span. Our goal in the next few years will be to identify mammalian systems suitable to study phosphate sensing, while further exploring Drosophila melanogaster as model organism. Relevant readouts for humans will be the homeostatic regulation of synthesis and secretion of PTH, 1,25-D, FGF23 by phosphate and it’s metabolic effects on life-span in genetic disorders such as familial hyperphosphatemic tumoral calcinosis (FHTC) and in chronic kidney disease.

Medical Subject Headings (MeSH)

Genetic Diseases, Inborn; Nephrocalcinosis; Phosphate Transport Proteins; Phosphorus Metabolism Disorders; Rickets; Signal Transduction

Research at a Glance

Yale Co-Authors

Frequent collaborators of Clemens Bergwitz's published research.

Publications

2024

2023

2022

  • X-Linked Hypophosphatemic Rickets, Treatment
    Bergwitz, C Clinical Keys X-Linked Hypophosphatemic Rickets, Treatment, Elsevier, 2022, https://www.elsevier.com/products/clinicalkey
    Peer-Reviewed Reviews, Practice Guidelines, Standards, and Consensus Statements

2021

Clinical Trials

Current Trials

Academic Achievements & Community Involvement

  • activity

    Association of Osteobiology

  • activity

    Advances in Mineral Metabolism (AIMM)

  • activity

    American Society of Bone and Mineral Research (ASBMR)

  • activity

    ASBMR Annual Meeting, Washington, DC

  • activity

    Skeletal Biology Development and Disease (SBDD), NIH

Clinical Care

Overview

Clemens W.H. Bergwitz, MD, is an endocrinologist at Yale Medicine who sees patients with hypophosphatemic disorders, osteoporosis, primary hyperparathyroidism, hyperthyroidism, thyroid nodules, and hypogonadism, as well as adrenal and general endocrine disorders.

Dr. Bergwitz’s characterizes the endocrine system as the human body’s own data messaging system. “It sends information to regulate some of our body’s most critical functions,” he says. In addition to treating patients, Dr. Bergwitz conducts research on many of these conditions, and his lab has worked on projects that test various therapies for hereditary endocrine disorders. “I am really a physician-scientist. My patients inspire my research, which eventually leads back to the bedside,” he says.

Dr. Bergwitz believes that patients should be the expert of their own illness. He strives to explain conditions and treatments in plain language so that patients not only understand their disorder, but also the biological mechanisms behind it. “I’m interested in providing my patients with the information they need to not only understand their condition, but to empower them to take good care of themselves,” he says.

Clinical Specialties

Endocrinology

Fact Sheets

Board Certifications

  • Certified Clinical Densitometrist

    Certification Organization
    The International Society for Clinical Densitometry
    Original Certification Date
    2015
  • Endocrinology Diabetes & Metabolism

    Certification Organization
    AB of Internal Medicine
    Latest Certification Date
    2016
    Original Certification Date
    2005
  • Internal Medicine

    Certification Organization
    AB of Internal Medicine
    Latest Certification Date
    2016
    Original Certification Date
    2004

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Contacts

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