Test Code: 1135

Leber Congenital Amaurosis: Deletion/Duplication Panel
Test Code: 1135
Turnaround time: 3 weeks

CONDITION DESCRIPTION

Leber congenital amaurosis (LCA) is characterized by poor vision beginning between birth or early childhood, nystagmus, an initially normal fundus exam and a nonrecordable electroretinogram (ERG). In addition, other typical findings include defective pupillary responses, photophobia, and the characteristic Franceschetti’s oculo-digital sign. Over time, macular coloboma and pigmentary retinopathy may develop. Due to the early manifestation of LCA, other syndromic or nonsyndromic conditions may be incorrectly diagnosed as LCA. LCA is most commonly inherited in an autosomal recessive manner.

Please note, the NMNAT1 gene is not included in the NGS panel at this time due to presence of at least four pseudogenes. For clinicians that would like NMNAT1 analysis in the event that all other genes test negative, we request that you contact CEN4GEN.

References:

  • Daiger et al. (1998) Invest Ophthalmol Vis Sci 39:S295.
  • OMIM
  • GeneReviews

GENES
AIPL1, CABP4, CEP290, CNGA3, CNGB3, CRB1, CRX, GNAT2, GUCY2D, IMPDH1, IQCB1, KCNJ13, LCA5, LRAT, OTX2, PDE6C, PDE6H, RD3, RDH12, RPE65, RPGRIP1, SPATA7, TULP1

INDICATIONS
This test is indicated for:

  • Confirmation of a clinical diagnosis of Leber congenital amaurosis.
  • Carrier testing in adults with a family history of Leber congenital amaurosis.

METHODOLOGY

Deletion/Duplication Analysis: DNA isolated from peripheral blood is hybridized to a gene-targeted CGH array to detect deletions and duplications. The targeted CGH array has overlapping probes that cover the entire genomic region.

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.

DETECTION

Deletion/Duplication: Detection is limited to duplications and deletions. The CGH array will not detect point or intronic pathogenic variants. Results of molecular analysis must be interpreted in the context of the patient’s clinical and/or biochemical phenotype.

SPECIMEN REQUIREMENTS

Submit only 1 of the following specimen types

Type: Whole Blood
Specimen Requirements: In EDTA (purple top) tube: Infants (2 years): 3-5 ml
Older Children & Adults: 5-10 ml.

Specimen Collection and Shipping: Ship sample at room temperature with overnight delivery.

Type: Isolated DNA
Specimen Requirements: In microtainer: 10 μg
Isolation using the QiagenTM Puregene kit for DNA extraction is recommended.

Specimen Collection and Shipping: Refrigerate until time of shipment in 100 ng/ul of TE buffer. Ship sample at room temperature with overnight delivery.

SPECIAL INSTRUCTIONS
Please include fundus photographs, electroretinogram (ERG) findings, visual field findings, and visual acuity, if available, for expert review and clinical correlation with test results.

RELATED TESTS

  • Eye Disorders: Comprehensive Sequencing and Deletion/Duplication Panels.
  • Leber Congenital Amaurosis: Sequencing Panel.