NAIL-PATELLA SYNDROME
LMX1B Sequencing
DNA ANALYSIS

Nail-Patella syndrome (NPS, MIM # 161200) is a pleiotropic autosomal dominant disorder characterized by a classic tetrad of features involving nails, knees, elbows and iliac horns. The nail changes are the most frequent feature and range from absent, to hypoplastic to dysmorphic. The patella may be small, irregularly-shaped or absent. The elbows may show limited extension, pronation and supination. The iliac horns are bilateral, conical, bony processes projecting posteriorly and laterally from the central part of the iliac bones of the pelvis. Approximately 30%-50% show renal involvement, which is first manifest as proteinuria with or without hematuria and can progress to renal failure in about 5% of patients. There are reports of patients with Nail-Patella glomerulopathy without associated constitutional abnormalities. Primary open-angle glaucoma and ocular hypertension also occur at increased frequency and at a younger age than in the general population. LMX1B is the only gene known to be associated with NPS. Sequence analysis of the entire LMX1B gene associated with Nail-Patella syndrome is available on a clinical basis at the Medical Genetics Laboratories at Baylor College of Medicine.

Reasons for Referral:

Confirmation of clinical diagnosis of Nail-Patella syndrome.
Prenatal diagnosis (known mutation only).

Testing Methodology:

Full Sequencing: A PCR-based assay is used to amplify all 8 exons of the LMX1B gene. Direct sequencing of amplification products is performed in both the forward and reverse directions using automated fluorescence dideoxy sequencing methods.

Sensitivity:

Clinical: Approximately 85%
Analytical: > 98%

Specimen Requirements:

Blood for DNA: EDTA (purple-top) tubes: Adult/Child: Minimum 6-14 cc
Requisition form must accompany the specimen. Prior to any genetic testing, we recommend genetic counseling and we request that the subject sign our consent statement and submit it with the sample. To receive forms, additional information or specimen collection kits, please contact the laboratory. Please call laboratory for specific requirements for prenatal testing.

Turnaround Time:

Index: 4 weeks
Known Familial Mutation: 3 weeks

CPT Codes and Prices:

Index: 83904x16, 83912, 83909x16, 83898x8, 83894, 83891
Known Familial Mutation: 83904x2, 83912, 83909x2, 83898, 83891, 83894

References:

1. Dunston JA, et al. (2004) The human LMX1B gene: transcription unit, promoter, and pathogenic mutations. Genomics 84: 565-576.

Shipping Information

Forms:

>> Gene Sequencing Requisition
>> Prenatal Requisition

Test Codes:

Index: 6270
Known Familial Mutation: 6275
Prenatal (Known Familial Mutation Only): 6280