Neuronal Ceroid Lipofuscinoses NGS Panel

Turnaround Time

5 weeks

CPT Code(s)

81479

Cost

$2,500

Genes

• Neuronal Ceroid Lipofuscinosis
• Neuronal Ceroid Lipofuscinosis Type 1 (CLN1)
• Neuronal Ceroid Lipofuscinosis Type 2 (CLN2)
• Neuronal Ceroid Lipofuscinosis Type 3 Batten Disease

The neuronal ceroid-lipofuscinoses (NCLs) are a genetically heterogenous group of neurodegenerative lysosomal storage disorders. While most are autosomal recessive, there is at least one autosomal dominant NCL. The severity and phenotype varies within this group of disorders, but almost all are characterized by progressive cognitive and motor deterioration as well as seizures. Vision loss, developmental delay, ataxia, intellectual disability, and early death are also common within the group of NCLs. Age of onset can range from infantile to childhood to adult onset. Gene List and Phenotypes CLN3 - Neuronal Ceroid Lipofuscinosis 3; Batten Disease CLN4 - Neuronal Ceroid Lipofuscinosis 4B, AD CLN5 - Neuronal Ceroid Lipofuscinosis 5 CLN6 - Neuronal Ceroid Lipofuscinosis 6 CLN8 - Neuronal Ceroid Lipofuscinosis 8 CTSD - Neuronal Ceroid Lipofuscinosis 10 PPT1 - Neuronal Ceroid Lipofuscinosis 1 TPP1- Neuronal Ceroid Lipofuscinosis 2 MFSD8 - Neuronal Ceroid Lipofuscinosis 7

For patients with a specific suspected disorder, individual gene sequencing should be considered first. Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutations within a family to allow for carrier testing and prenatal diagnosis.

Next Generation Sequencing

The current design of this panel covers all genes and the flanking intronic sequences. This method allows for analysis of greater than 98% of the targeted sequence for the detection of nucleotide substitutions and small deletions and duplications. Large deletions and duplications will not be detected by this panel. Mutations and variants identified on the panel are confirmed with Sanger sequencing. All novel and apparently pathogenic changes are reported when found within the coding region as well as within 10 basepairs of each intron/exon boundary for each gene. Promoter and 3' untranslated sequences are not included in the current analysis. It should be noted that the current protocol is not specifically designed to detect copy number alterations and single exon deletions may require additional follow-up to determine whether or not they represent technical artifacts. We recommend further array-based testing to more accurately address the concerns of dosage alterations. The Cytogenetic Laboratory at GGC offers a high resolution whole genome SNP microarray. The GGC Diagnostic Laboratory Directors are available for further consultation regarding the limitations of the NGS and array testing procedures.

The preferred sample type is 3-5 ml of peripheral blood collected in an EDTA (purple top) tube. Extracted DNA and saliva are also accepted for this test. Saliva samples must be submitted in an approved saliva kit. Contact the lab to receive a saliva kit or to have one sent to your patient.

The specimen should be kept at room temperature and delivered via overnight shipping. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.

If the pathogenic mutation(s) are identified in an affected individual using this panel, prenatal diagnosis is available for future pregnancies. Sanger sequencing will be used for prenatal diagnosis when there is a known familial mutation. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.