Triphalangeal Thumb Polydactyly

Triphalangeal thumb (TPT) is the hallmark feature in individuals with mutations in the zone of polarizing activity regulatory sequence (ZRS), which is contained within intron 5 of the LMBR1 gene. Mutations in ZRS have been reported in individuals with PPD2 (TPT with or without preaxial polydactyly), TPT polysyndactyly, syndactyly IV (complete syndactyly with polydactyly), and Werner mesomelic syndrome (tibial hypoplasia, polysyndactyly, TPT).

Tests Available

Forms and Documents

Test Details

LMBR1
  • Confirmation of a clinical diagnosis
  • Differentiation from other causes of syndromic and isolated limb abnormalities
  • Prenatal diagnosis in families with a known mutation
  • Capillary Sequencing

Ordering

502
4 weeks
2-5 mL Blood - Lavender Top Tube
Oral Rinse (30-40 mL)|Buccal Swabs

Billing

81479x1
No
Yes
  • 759.7 Multiple congenital anomalies, so described Congenital: anomaly, multiple NOS deformity, multiple NOS
  • 755 Other congenital anomalies of limbs Excludes: those deformities classifiable to 754.0-754.8
  • 755.00 Polydactyly, unspecified digits Supernumerary digits
  • 755.1 Syndactyly Symphalangy Webbing of digits
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References

  1. Furniss et al., (2008) Hum Mol Genet 17(16):2417-2423.
  2. Wu et al., (2009) Am J Med Genet Part A 149A:816-818.
  3. Wieczorek et al., (2010) Hum Mutat 31(1):81-89.
  4. Sun et al., (2008) J Med Genet 45:589-595.
  5. Semerci et al., (2009) Clin Genet 76:85-90.
  6. Klopocki et al., (2008) J Med Genet 45:370-375.
  7. Furniss et al., (2009) J Med Genet 46:730-735.
  8. Gurnett et al., (2007) Am J Med Genet Part A 143A:27-32.