Our Team

Our Team Our Mission Request an Appointment Definition of Hypotonia Conditions Associated with Hypotonia Research View or Print Brochure

Our team believes that without effective collaborations, one cannot reach truth.  We therefore work closely together with expert physicians and health care professionals in a variety of disciplines including: genetics, neurology, developmental pediatrics, gastroenterology, ophthalmology, orthopedic surgery, pulmonology, cardiology, rehabilitation medicine and physical and occupational therapy.  In collaboration with the neuromuscular laboratory, extensive histological and immunohistochemical evaluation of skeletal muscle will be guaranteed.  This way we ensure the most sophisticated approach to diagnosis and treatment of patients with various conditions associated with hypotonia.

The center is able to offer a broad range of diagnostic evaluations including: chromosomal studies, neurometabolic studies, molecular diagnostic testing, radiologic, neurophysiological and neuroradiological studies as well as muscle biopsies if indicated.

An appointment in our clinic typically involves a visit with Dr. Cohn and the genetics team and is approximately 2-3 hours, depending on studies ordered following our visit. However, we may also recommend ancillary appointments on the same day as our appointment (i.e. echocardiogram, appointment with developmental pediatrics, etc.). This will be evaluated when we are taking initial intake information prior to scheduling an appointment.

The Johns Hopkins Center for Hypotonia Team:

Ronald D. Cohn, M.D.
Director Johns Hopkins Center for Hypotonia
McKusick-Nathans Institute of Genetic Medicine
Assistant Professor of Pediatrics, Neurology and Genetic Medicine

Maria Ronningen Johnson, MS CGC
Genetic Counselor
McKusick-Nathans Institute of Genetic Medicine

Dawn Weems
Clinic Coordinator
McKusick-Nathans Institute of Genetic Medicine
Ph: 410-955-3122

Other physicians to whom we often refer patients and/or collaborate with:

Neurology: Thomas O. Crawford, M.D. and Kathryn R. Wagner, M.D. Ph.D

Polymyositis Center: Lisa Christopher, M.D. and Andrew Mammen, M.D.

Neuromuscular Laboratory:  Andrea Corse, M.D.

Developmental Pediatrics:  Mary Leppert, M.D. (Kennedy Krieger Institute)

Gastroenterology: Maria Oliva-Hemker, M.D.

Swallow dysfunction: Maureen Lefton-Grief, M.D.

Cardiology:  Reid Thompson, M.D.

Pulmonary:  Laura Sterni, M.D.

Orthopedic surgery:  Paul Sponseller, M.D.

Rehabilitation Medicine: Kennedy Krieger Institute OT/PT