338 THE FG SYNDROME: FROM 1974-2004

• Published in: Journal of investigative medicine Vol. 53; no. 1; p. S137
• Main Authors: Smith, J. F., Wayment, R. O., Opitz, J. M.
• Format: Journal Article
• Language: English
• Published: London Sage Publications Ltd 01.01.2005
• ISSN: 1081-5589; 1708-8267
• DOI: 10.2310/6650.2005.00005.337

FG syndrome is an X-linked disorder comprising developmental delay, congenital hypotonia, characteristic facial appearance, large head relative to length or height, and other anomalies affecting the genitourinary, gastrointestinal, and musculoskeletal systems. Previous work has demonstrated the range of anomalies seen in FG syndrome, but no single study has presented all of the anomalies in a large series of patients. We retrospectively reviewed 177 FG syndrome patients in our Opitz Clinical Genetics Research charts to identify the relative frequencies of characteristic historical and physical findings. The purpose of this study was to accomplish the following: 1. Attempt to summarize the spectrum of anomalies seen in FG syndrome in patients from the earliest cases in the 1970's to those seen in a clinical genetics practice in 2004. 2. Identify aspects of this presentation that may help elucidate the pathogenetic mechanisms responsible for the disorder. 3. Determine which specific clinical traits are associated with severe forms of the disorder. We identified abnormalities of the head in 81%, of the face in 86%, the musculoskeletal or skin systems in 81% and 49%, respectively, constipation in 50%, neurological abnormalities in 81%, cardiac defects in 41%, genitourinary anomalies in 40%, and developmental delay in 84%. Radiographic findings were seen in 42% of our patients. Corpus callosum thinning or hypoplasia was identified in 18% and absence of corpus callosum was seen in 10%. A tethered cord was clearly diagnosed in 2%. No placental abnormalities were detected in any mother. From our most recent work, it appears that there may be an increased incidence of autoimmune disorders in carrier women including lupus, scleroderma, autoimmune pericarditis, multiple sclerosis, Crohn disease, and “fibromyalgia.” Furthermore, there may be a predisposition to bipolar disorder and anxiety/panic disorders. Based on these findings, we conclude that FG syndrome is seen in a wide range of clinical settings. Severely affected individuals will often benefit from genetic insights into other aspects of their care not commonly seen by primary care physicians. Future work will attempt to determine the relationship between genotype and phenotype in a more rigorous fashion, particularly after the cloning of the four FGS genes mapped so far. Since FGS overlaps extensively with the GBBB syndrome, it is postulated that FGS will also be related to a microtubular-associated protein (MAP) abnormality.