The UC Davis NF/Ras Pathway Clinic provides comprehensive health care support and management for children and adults throughout their life span who have or are at risk for having a Ras pathway disorder. We have an expansive NF/Ras Pathway Referral Network at the University of California. Our comprehensive network consists of more than 100 specialists at UC Davis who have expertise in Ras pathway disorders. These specialists include dermatologists, developmental pediatricians, gastroenterologists, gynecologists, hematologists, nephrologists, neurologists, neurosurgeons, obstetricians, oncologists and others. We provide comprehensive support to our patients and ongoing consultative assistance for primary care providers caring for individuals with a Ras pathway disorder. Our clinic is uniquely located at the UC Davis MIND Institute, a leader in treatment of neurodevelopmental disorders. Our goal is to provide the up-to-date best medical practices for patients and families with RASopathies and to bring innovation and discovery to the clinic.

The RASopathies are a clinically defined group of medical genetic syndromes caused by germline alterations in genes that encode components or regulators of the Ras/mitogen-activated protein kinase (MAPK) pathway. Recently the NF/Ras Pathway Genomic Medicine Clinic has expanded to include disorders caused by germline or somatic mutations encoding more downstream components of the Ras pathway. Together, the RASopathies represent one of the largest groups of genetic syndromes affecting greater than 1 in 1000 individuals.

The Ras pathway is a critical signaling mechanisms that controls growth and development of cells in our body and has been well studied in cancer research. This pathway works by moving information from outside of the cell towards the inside of the cell as it makes its way to the final target. The Ras pathway is one of many signaling pathways the body utilizes. If any of the signal transmitters in the Ras pathway is not functioning properly, the final target does not get the proper message. There are numerous signals transmitted in the Ras pathway. Changes (mutations) in the genes that provide information along this pathway can alter an individual's growth and development. Such changes can result in a Ras pathway disorder, also known as a RASopathy.

Ras Pathway Disorders (RASopathies) and Clinical Features

Neurofibromatosis type 1 (NF1)

  • Café au lait macules (dark skin spots)
  • Freckling in armpits and groin
  • Neurofibromas (nerve tumors)
  • Developmental delay and learning disabilities
  • Short stature
  • Macrocephaly (large head circumference)

Neurofibromatosis type 2 (NF2)

  • Schwannomas, especially bilateral vestibular schwannomas (tumors of the cells covering neurons)
  • Meningiomas (tumors of membrane surrounding central nervous system)


  • Schwannomas (tumors of the cells covering neurons)
  • Meningiomas

Legius syndrome (also known as NF-1 like)

  • Café au lait macules (dark skin spots)
  • Freckling in armpits and groin

Capillary malformation-arteriovenous malformation Syndrome

  • Capillary malformations, of the skin or inside the body

Noonan syndrome

  • Characteristic facial features
  • Lentigenes and café noir spots (types of dark freckles)
  • Short stature
  • Pulmonary valve stenosis or other heart defect

Noonan syndrome with multiple lentigines (NSML; formally known as LEOPARD syndrome)

  • Lentigines (a type of dark freckle)
  • Hearing loss
  • Pulmonary valve stenosis or other heart defect/abnormality
  • Short stature

Costello syndrome

  • Coarse facial features
  • Heart defect (e.g., pulmonary valve stenosis, hypertrophic cardiomyopathy and others)
  • Failure to thrive
  • Developmental delay
  • Deep palmar and plantar creases

Cardio-facio-cutaneous syndrome (CFC)

  • Characteristic facial features
  • Heart defect (e.g., pulmonary valve stenosis, hypertrophic cardiomyopathy and others)
  • Skin rashes and sparse hair
  • Developmental delay
  • Severe gastrointestinal problems
  • Failure to thrive

PTEN hamartoma tumor syndrome

  • Macrocephaly (large head circumference)
  • Multiple hamartomas (a type of tumor), especially of the thyroid, breast, endometrium

Megancephaly-capillary malformation-polymicrogyria (MCAP) syndrome

  • Increased birth length and weight
  • Overgrowth
  • Capillary malformations of the skin
  • Seizures
  • Developmental delay

Proteus syndrome

  • Overgrowth of tissues

Tuberous sclerosis complex (TSC 1/2)

  • Hypomelanotic (lighter than skin color) macules
  • Facial angiofibromas or plaques
  • Developmental delay
  • Cardiac rhabdomyosacromas (tumors of heart muscle)
  • Kidney tumors

A Pathway-Based Clinic

Due to the common cell signaling of the Ras pathway, the medical and psycho-social issues faced by individuals and families with Ras pathway disorders have a great deal of overlap. A pathway-based clinic offers more effective medical management and treatment, as well as leading-edge translational research opportunities. Multidisciplinary care and management of individuals with genetic disorders, including those of the Ras pathway, can be challenging for the family, the primary care physician, and the specialists involved in a patient's care. Our clinic was designed to address these challenges and connect families and clinicians with all of the available resources.

The clinic's pathway-based approach has unique attributes that include comprehensive case management and multidisciplinary referrals; the NF/Ras Pathway Referral Network of more than 100 specialists in Northern California and facilitated transition from pediatric to adult care in all specialties.

Katherine A. Rauen, M.D., Ph.D. - Genomics, Genetics

Katherine A. Rauen, M.D., Ph.D.

The NF/Ras Pathway Clinic was originally founded by Dr. Katherine Rauen in 2007 at UCSF. In 2014 the clinic expanded to UC Davis. Dr. Rauen is the world's leading expert in the RASopathies and has extensive expertise in the clinical, medical, and psychosocial care of individuals with disorders of the Ras pathway. Her Ras pathway research is internationally recognized and she has published extensively in this field.

Suma Shankar

Suma P. Shankar, M.D., Ph.D., FACMG
Associate Professor

Dr. Suma Shankar has been involved in caring for individuals with RASopathies since 2007 and has actively served as a Medical expert on the boards for CFC and Costello family support groups. She specializes in studying the ocular manifestations of RASopathies and has several abstracts and presentations on RASopathies.

Colette DeFilippo

Colette DeFilippo, M.S., L.C.G.C.
Genetic Counselor

Contact Information

Appointment Scheduling
Phone: 916-703-0317
Fax: 916-703-0350


If you are already a UC Davis patient, please ask your primary care physician to refer you to the UC Davis NF/Ras Pathway Genetics Clinic in the Department of Pediatrics, Division of Genomic Medicine at the MIND Institute in Sacramento, CA.

If you are not yet a UC Davis patient, you will most often need your primary care physician to refer you. Outside providers can refer a patient to the UC Davis NF/Ras Pathway Genetics Clinic by calling the UC Davis Physician Referral Line at (800) 4-UCDAVIS (916-482-3284), or by visiting the Outpatient Referrals Website to start the referral process. Please ask your physician to include in the referral recent test results related to your condition and a list of the medications that you take and their doses.


The UC Davis/Ras Pathway Genetics Clinic is located at the MIND Institute on the UC Davis Medical Center Main Campus in Sacramento, CA.

UC Davis MIND Institute
2825 50th Street
Sacramento, CA 95817
Directions to MIND Institute

What to Bring to Clinic

  • If you are a new patient, a completed New Patient Questionnaire  (PDF)
  • Health insurance card
  • Copies of any medical records you have
  • Names and phone numbers of other providers you see
  • Photographs of when you were younger
  • Copies of developmental assessments (performed by the Regional Center, School District, or elsewhere)
  • Copies of affected family member's medical records and photographs
  • A list of your questions
  • Pen and paper to take notes
  • Please be prepared to answer medical history questions about your family members on both your mother's and father's side

Resources for Family Support and Advocacy