This test analyzes the OFD1 gene, which is the only known gene that is associated with oral-facial-digital syndrome type I (OFD1). OFD1 is an X-linked dominant disorder with lethality in males; it is associated with dysfunction of the primary cilia.
Genetic testing can provide an accurate diagnosis, which can impact an individual’s medical management, help predict disease progression and outcome, and indicate the recurrence risk.
OFD1 is a member of a class of disorders called ciliopathies. Ciliopathies share many overlapping symptoms, often making it difficult to distinguish between them based on clinical presentation alone. Depending on the individual’s clinical and family history, the broader Invitae Ciliopathies Panel may be appropriate. It can be ordered at no additional cost.
Oral-facial-digital syndrome type I (OFD1) is an X-linked dominant developmental disorder that primarily affects the mouth, facial features, and fingers and toes. Symptoms associated with the brain and kidneys may also occur. Oral symptoms include lobed tongue, benign tumors (hamartomas and lipidomas) of the tongue, cleft palate, and oligodontia. Facial features include telecanthus, cleft lip, micrognathia, and hypoplasia of the alae nasi. Digital symptoms include brachydactyly, syndactyly, clinodactyly, and polydactyly. Additional symptoms associated with OFD1 are brain malformations (agenesis of the corpus callosum, cerebellar agenesis, and Dandy-Walker malformation) and the development of cysts in the brain and kidneys. Mild intellectual disability is not uncommon.
Approximately 85% of individuals with oral-facial-digital syndrome type 1 have an identifiable pathogenic variant in the OFD1 gene.
OFD1 is inherited in an X-linked dominant pattern with lethality in males.
OFD1 is a highly penetrant condition with variable expression. OFD1 is lethal in males; nearly all affected individuals are female. The majority of individuals are diagnosed at birth with classic abnormalities noted in the mouth, face and digits; however, some adult females have been reported with absent clinical features until the clinical diagnosis of polycystic kidney disease in adulthood.
Approximately 75% of OFD1 cases are reported with no family history of the disorder.
The prevalence estimates of OFD1 range from 1:250,000 to 1:50,000.
Oral-facial-digital syndrome testing is indicated for any individual who has clinical features that are consistent with OFD1 or a first-degree relative with OFD1.
Invitae is a College of American Pathologists (CAP)-accredited and Clinical Laboratory Improvement Amendments (CLIA)-certified clinical diagnostic laboratory performing full-gene sequencing and deletion/duplication analysis using next-generation sequencing technology (NGS).
Our sequence analysis covers clinically important regions of each gene, including coding exons, +/- 10 base pairs of adjacent intronic sequence in the transcript listed below. In addition, analysis covers the select non-coding variants specifically defined in the table below. Any variants that fall outside these regions are not analyzed. Any specific limitations in the analysis of these genes are also listed in the table below.
Based on validation study results, this assay achieves >99% analytical sensitivity and specificity for single nucleotide variants, insertions and deletions <15bp in length, and exon-level deletions and duplications. Invitae's methods also detect insertions and deletions larger than 15bp but smaller than a full exon but sensitivity for these may be marginally reduced. Invitae’s deletion/duplication analysis determines copy number at a single exon resolution at virtually all targeted exons. However, in rare situations, single-exon copy number events may not be analyzed due to inherent sequence properties or isolated reduction in data quality. Certain types of variants, such as structural rearrangements (e.g. inversions, gene conversion events, translocations, etc.) or variants embedded in sequence with complex architecture (e.g. short tandem repeats or segmental duplications), may not be detected. Additionally, it may not be possible to fully resolve certain details about variants, such as mosaicism, phasing, or mapping ambiguity. Unless explicitly guaranteed, sequence changes in the promoter, non-coding exons, and other non-coding regions are not covered by this assay. Please consult the test definition on our website for details regarding regions or types of variants that are covered or excluded for this test. This report reflects the analysis of an extracted genomic DNA sample. In very rare cases, (circulating hematolymphoid neoplasm, bone marrow transplant, recent blood transfusion) the analyzed DNA may not represent the patient's constitutional genome.
|Gene||Transcript reference||Sequencing analysis||Deletion/Duplication analysis|