Borjeson-Forssman-Lehmannsyndrome (BFLS) is an X-linked intellectual disability syndrome. Characteristics ofthis syndrome include severe mental defect, epilepsy, hypogonadism,hypometabolism, marked obesity, swelling of subcutaneous tissue of face, narrowpalpebral fissure, and large but not deformed ears. Affected individuals mayhave a characteristic facial appearance consisting of prominent superciliaryridges, deep-set eyes, ptosis, and large ears.
Thephenotype of BFLS seems to evolve with age. Generally, babies with BFLS arefloppy, with failure to thrive, big ears, and small external genitalia. Inchildhood, boys may display learning problems and moderate short stature, withemerging truncal obesity and gynecomastia. Head circumference is usuallynormal, and macrocephaly may be seen. Big ears and small genitalia remain. Thetoes are short and fingers tapered and malleable. In late adolescence and adultlife, the classically described heavy facial appearance emerges.
Someheterozygous females display milder clinical features such as tapering fingersand shortened toes. Significant learning problems have been reported inapproximately 20% of female carriers, and skewed X inactivation inapproximately 95%. Carrier females have also been reported with epilepsy,characteristic facial feratures, obesity, amenorrhea, and hypothyroidism.
Mutationsin the PHF6 gene (Xq26.3) have beenassociated with BFLS.
For patients with suspected BFLS, 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.
Click here for the OMIM summary on this condition.
This test is indicated for:
- Confirmation of a clinical/biochemical diagnosis of Borjeson-Forssman-Lehmann syndrome.
- Carrier testing in adult females with a family history of Borjeson-Forssman-Lehmann syndrome.
Clinical Sensitivity: Unknown. Mutations in the promoter region, some mutations in the introns and other regulatory element mutations cannot be detected by this analysis. Large deletions will not be detected by this analysis. Results of molecular analysis should be interpreted in the context of the patient's biochemical phenotype.
Analytical Sensitivity: ~99%
Infants and Young Children (<2 years of age): 2-3 ml
Children > 2 years of age to 10 years old: 3-5 ml
Older Children & Adults: 5-10 ml
Autopsy: 2-3 ml unclotted cord or cardiac blood
Isolation using the Perkin Elmer™Chemagen™ Chemagen™ Automated Extraction method or Qiagen™ Puregene kit for DNA extraction is recommended.
Orangene™ Saliva Collection Kit used according to manufacturer instructions. Please contact EGL for a Saliva Collection Kit for patients that cannot provide a blood sample.
Submit copies of diagnostic biochemical test results with the sample, if appropriate. Contact the laboratory if further information is needed.
Sequence analysis is required before deletion/duplication analysis by targeted CGH array. If sequencing is performed outside of EGL Genetics, please submit a copy of the sequencing report with the test requisition.
- Deletion/duplication analysis of the PHF6 gene by CGH array is available for those individuals in whom sequence analysis is negative (YI).
- A CGH array-based test for deletion/duplication analysis of 64 different X-linked intellectual disability genes is available (OL).
- 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 to adult females who are confirmed carriers of mutations. Please contact the laboratory genetic counselor to discuss appropriate testing prior to collecting a prenatal specimen.