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FG Syndrome Type 1

It is possible that the main title of the report FG Syndrome Type 1 is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • FGS1
  • Opitz-Kaveggia syndrome

Disorder Subdivisions

  • None

General Discussion

FG syndrome type 1 (FGS1) is an X-linked genetic disorder that is characterized by poor muscle tone (hypotonia), intellectual disability, constipation and or anal anomalies and complete or partial absence of the part of the brain that connects the two hemispheres of the brain (corpus callosum). Other features of the disorder are small and simple ears, tall and prominent forehead, wide and flat thumbs and great toes and downslanting eyes.

FGS1 is an X-linked genetic disorder caused by a recurrent abnormality (mutation) in the MED12 gene. The spectrum of disorders caused by mutations in this gene is still being defined. Some individuals previously diagnosed with FG syndrome do not have a MED12 gene mutation and, therefore, probably have a different reason for intellectual disability.


FG Syndrome Family Alliance
922 NW Circle Blvd
Suite 160 PMB 290
Corvallis, OR 97330
Tel: (617)577-9050

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223

Madisons Foundation
PO Box 241956
Los Angeles, CA 90024
Tel: (310)264-0826
Fax: (310)264-4766

For a Complete Report:

This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site or email

Last Updated: 1/5/2012
Copyright 1991, 1999, 2007, 2008, 2012 National Organization for Rare Disorders, Inc.

WebMD Medical Reference from the National Organization for Rare Disorders

Last Updated: May 28, 2015
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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