Limb disorders

Gene: TCTN3

Comment on list classification: Gene made grey as it is green on the Rare multisystem ciliopathy disorders panel (v1.78) and the ciliopathy panel will be applied if a patient is suspected of having a ciliopathy, or the possibility of a ciliopathy cannot be excluded.

Created: 2 Dec 2018, 11:11 p.m.

Comment when marking as ready: Sufficient cases (>3) of polydactyly in patients with TCTN3 homozyous/compound het variants.

Created: 15 Oct 2018, 3:49 p.m.

Comment on list classification: Updated rating from Red to Green: Confirmed DD-G2P gene for Orofaciodigital syndrome IV, 258860 (Mohr-Majewski syndrome) which can present with Polydactyly, Brachydactyly, Clinodactyly or Syndactyly. >3 polydactyly cases from multiple populations reported in consanguineous families in PMID:22883145. Multiple variants identified in this paper (homozgyous or compound heterozygous).

Created: 15 Oct 2018, 3:47 p.m.

Thomas et al. 2012 (PMID:22883145) identified a nonsensense variant in TCTN3 in an aborted fetus born to a consanguineous Senegal family. Amongst other features, the fetus had polydactyly of four limbs and bowing of long bones with severe tibia hypoplasia. They identified 2 additional homozygous variants in three other fetuses (from Pakistan and Tunisia), all of whom displayed polydactyly (Table 1) together with bone defects including femoral bowing and club foot. They also reported compound heterozygous variants in 2 French fetal siblings with Orofaciodigital syndrome IV, 258860 including polydactyly. Additionally they report 2 Turkish siblings with Joubert syndrome (MIM:614815) and homozygous TCTN3 variants; one was reported with polydactyly.

Created: 15 Oct 2018, 3:41 p.m.

Comment on mode of inheritance: Biallelic MOI supported by OMIM and Gene2Phenotype.

Created: 15 Oct 2018, 3:40 p.m.