FG Syndrome Type 1
FG syndrome type 1 (FGS1) is clinically diagnosed when six of the following eight features are present: intellectual disability, hypotonia, constipation and/or anal anomalies, small and simple ears, tall and prominent forehead, downslanting palpebral fissures, broad thumbs and halluces, and abnormalities of the corpus callosum. Additional features that can be seen in individuals with FGS1 are friendly, hyperactive, attention-seeking behavior; macrocephaly; and hypertelorism. FGS1 is caused by a recurrent p.ARG961Trp mutation in the MED12 gene (Xq13).
Lujan syndrome is clinically diagnosed when six of the following eight features are present: intellectual disability, hypotonia, macrocephaly, tall, thin body habitus, long, thin face, high nasal root, high narrow palate, and short philtrum. Additional features that can be seen in individuals with Lujan syndrome are hypernasal speech, micrognathia, hyperextensible digits, and abnormalities of the corpus callosum. Lujan syndrome is caused by a recurrent p.Asn1007Ser mutation in the MED12 gene (Xq13).
Female carriers could develop clinical findings related to the disorders.
For patients with a suspected MED12-Related Disorder, sequence analysis is recommended as the first step in mutation identification. For patients in whom mutations are not identified by full gene sequencing, deletion/duplication analysis is appropriate.
- Confirmation of a clinical diagnosis of MED12-Related Disorders in an individual in whom sequence analysis was negative.
- Carrier testing in adults with a family history of MED12-Related Disorders in whom sequence analysis was negative.
Please note that a "backbone" of probes across the entire genome are included on the array for analytical and quality control purposes. Rarely, off-target copy number variants causative of disease may be identified that may or may not be related to the patient's phenotype. Only known pathogenic off-target copy number variants will be reported. Off-target copy number variants of unknown clinical significance will not be reported.
Analytical Sensitivity: ~99%
Submit only 1 of the following specimen types
Preferred specimen type: Whole Blood
Type: Whole Blood
Specimen Requirements:In EDTA (purple top) or ACD (yellow top) tube:
Infants (<2 years): 2-3 ml
Children (>2 years): 3-5 ml
Older Children & Adults: 5-10 ml
Specimen Collection and Shipping: Refrigerate until time of shipment. Ship sample within 5 days of collection at room temperature with overnight delivery.
Specimen Requirements:OrageneTM Saliva Collection kit (available through EGL) used according to manufacturer instructions.
Specimen Collection and Shipping: Store sample at room temperature. Ship sample within 5 days of collection at room temperature with overnight delivery.
- Sequence analysis of the MED12 gene by CGH array is available and is required before deletion/duplication analysis.
- Custom diagnostic mutation analysis (KM) is available to family members if mutations are identified by targeted mutation testing or sequencing analysis.
- Prenatal testing is available only for known familial mutations to individuals who are confirmed carriers of mutations. Please contact the laboratory genetic counselor to discuss appropriate testing prior to collecting a prenatal specimen.
- X-Linked Intellectual Disability panels are available for 30, 60, and 90 genes.