X-LINKED ANGELMAN-LIKE SYNDROME
SLC9A6 Sequencing
DNA ANALYSIS

X-linked Angelman-Like Syndrome (SLC9A6-Related Syndromic Mental Retardation) is characterized by micorcephaly, epilepsy, ataxia, and absent speech. The original three patients described had a phenotype that included profound developmental delay, seizures, ataxia, flexed arms, hyperkinetic behavior, and a happy demeanor with frequent smiling and spontaneous laughter. All three patients were originally suspected to have Angelman syndrome but tested negative. The pedigrees in these families suggested X-linked inheritance, and linkage analysis suggested linkage to Xq24-q27.3. Several genes in this region were sequenced for mutations, and mutations were identified in all three families in the SLC9A6 gene, which is localized to Xq26.3 and encodes the NHE6 Na +/H + exchanger protein. Sequence analysis of the entire SLC9A6 gene is available on a clinical basis at the Medical Genetics Laboratories at Baylor College of Medicine.

Reasons for Referral:

Confirmation of diagnosis in affected individuals
Testing of known familial mutations
Prenatal Diagnosis (known familial mutations)

Testing Methodology:

PCR amplification of the exons contained in the SLC9A6 gene coding region will be performed on patient genomic DNA. Direct sequencing of amplification products is performed in both the forward and reverse directions using automated fluorescence dideoxy sequencing methods.

Specimen Requirements:

Blood: EDTA (purple-top) tubes: Adults: 14 cc; Child: 6 cc; Infant: 2-3 cc
Requisition form must accompany specimen. Prior to any genetic testing, we recommend genetic counseling and request that the subject, or their legal guardian, sign our consent form and submit it with the sample. To receive our forms and information about prenatal testing, please contact our laboratory.

Turnaround Time:

4 weeks

CPT Codes and Prices:

Index: 83891, 83898x19, 83894, 83904x38, 83909x38, 83912
Known Familial Mutation: 83891, 83898, 83894, 83904x2, 83909x2, 83912

Shipping Information

Forms:

>> Gene Sequencing Requisition
>> Prenatal Requisition

Reference:

1. Gilfillan GD, Selmer KK, Roxrud I, Smith R, Kyllerman M, Eiklid K, Kroken M, Mattingsdal M, Egeland T, Stenmark H, Sjøholm H, Server A, Samuelsson L, Christianson A, Tarpey P, Whibley A, Stratton MR, Futreal PA, Teague J, Edkins S, Gecz J, Turner G, Raymond FL, Schwartz C, Stevenson RE, Undlien DE, Strømme P. SLC9A6 mutations cause X-linked mental retardation, microcephaly, epilepsy, and ataxia, a phenotype mimicking Angelman syndrome. Am. J. Hum. Genet. 2008; 82(4): 1003-1010.

Test Code:

Index: 6540
Known Familial Mutation: 6541
Prenatal (Known Familial Mutation only): 6542