Further study is needed to prove the function of 2 novel variants in the 5'UTR of HOXA2, and to explore the possible mechanism of these variants in the occurrence of microtia.
This study confirms the role of HOXA2 gene in dominant isolated microtia and contribute to further define the dysmorphogenetic effect of this gene on ear development.
We recommend consideration of EFTUD2 testing in individuals with features of oculo-auriculo-vertebral spectrum and bilateral microtia, or individuals with atypical CHARGE syndrome who do not have a CHD7 mutation, particularly those with a zygomatic arch cleft.
Identification of this causal mutation in the HMX1 gene indicates the role of this particular gene in the development of the external ear and provides a genetic marker for selection against microtia.
The coding regions of three genes, EVC known for cartilage development and NKX3-2, HMX1 involved in microtia, were selected for sequencing with 5 individuals from the pedigree.
The coding regions of three genes, EVC known for cartilage development and NKX3-2, HMX1 involved in microtia, were selected for sequencing with 5 individuals from the pedigree.
Auditory investigations, computer tomography, and genetic sequencing of the fibroblast growth factor 3 (FGF3) gene were performed on a Somali family presenting with autosomal recessive, hearing impairment, microdontia, and outer ear morphologies ranging from normal auricle development to microtia assessed as type 1 Weerda dysplasia in affected individuals.
Of note, we identified one EVC2 non-synonymous mutation (p.Asp1174Asn) as a potential disease-implicating variant for a human microtia-associated syndrome.
The low-frequency variants association study was used and highlighted several strong candidate genes <i>MUC4, MUC6, COL4A4, MYO7A, AKAP12, COL11A1, DSPP, ESPN, GPR98, PCDH15, BSN, CACNA1D, TPRN</i>, and <i>USH1C</i> for microtia (<i>P</i> = 2.51 × 10<sup>-4</sup>).
ATR-ATRIP patients are characterised by extremely severe microcephaly and growth delay, microtia (small ears), micrognathia (small and receding chin), and dental crowding.
We therefore report a mutational analysis of GSC, HOXA2 and PRKRA in 106 congenital microtia patients without any combined malformation to explore the relationship between GSC, HOXA2, PRKRA and nonsyndromic microtia.