Table 1. Mutations identified in connexin 50 in association with different cataract phenotypes in different congenital cataract families.

Amino acid change	Location/GJA8 Domain	Cataract type	Phenotype description	Origin of family	References
p.R23T	Cytoplasmic NH2-terminal	Congenital nuclear	Progressive, dense nuclear (fetal/embryonal)	Iranian	[23]
p.V44E	First transmembrane domain (M1)	Congenital cataract and microcornea	Total lens opacification	Indian	[24]
p.W45S	First transmembrane domain (M1)	Jellyfish-like cataract and microcornea	Axial lens opacity with finger-like projections extended in all directions	Indian	[25]
p.D47N	First extracellular loop (E1)	Nuclear pulverulent	Opacities confined to the fetal and embryonal nucleus	English	[26]
p.D47Y	First extracellular loop (E1)	Autosomal dominant congenital cataract	Autosomal dominant congenital cataract	Chinese	[27]
p.E48K	First extracellular loop (E1)	Zonular nuclear pulverulent	Non-progressive, fine dust-like opacities, more dense throughout the nucleus. Several cortical riders in the zonular region	Pakistani	[28]
p.V64G	First extracellular loop (E1)	Congenital nuclear	Congenital nuclear cataract	Chinese	[29]
p.V79L	Second transmembrane domain (M2)	Full moon like with Y-sutural opacities	Stationary cataract both Y-sutures affected. No opacities in the embryonal nucleus, fine granular white opacity outside the embryonal nucleus in the fetal nuclear region	Indian	[22]
p.P88Q	Second transmembrane domain (M2)	Lamellar pulverulent	Pulverulent opacities in the fetal nucleus, embryonal nucleus clear	English	[20]
p.P88Q	Second transmembrane domain (M2)	Balloon-like cataract with Y-sutural opacities	Fetal nucleus and Y-sutures affected. In between the Y-sutures, feathery opacities are present. Three riders present at the perimetry of opaque fetal nucleus. No “pulverized” dust-like opacities in the lens	Indian	present study
p.P88S	Second transmembrane domain (M2)	Zonular pulverulent	Non-progressive innumerable powdery opacities located in the nuclear and lamellar zones. Affects both the embryonic and fetal nucleus: “total nuclear cataract”	English	[10]
p.P189L	Second extracellular loop (E2)	Congenital cataract and microcornea	Star shaped nuclear opacity with a whitish central core	Danish	[30]
p.R198Q	Second extracellular loop (E2)	Cataract and microcornea	Posterior subcapsular	Indian	[24]
p.203fs	Second extracellular loop (E2)	Cataract and nystagmus	Total cataract and nystagmus	Indian	[31]
p.I247M	Cytoplasmic COOH-terminus	Zonular pulverulent	Progressive, non homogeneous opacity consisting of opaque particles of different sizes, most of these very small, distributed unequally in a disc of 5 mm in diameter in the center of the lens. Also a slightly cloudy inhomogeneous area of 2 mm at posterior pole	Russian	[32]
p.S276F	Cytoplasmic COOH-terminus	Pulverulent nuclear	White granular opacities in fetal and embryonal nucleus	Chinese	[33]

This table provides information on specific mutations identified in different domains and regions of connexin 50 in association with congenital cataract in families belonging to different ethnic groups. Most of these mutations are missense mutations, and the cataract phenotypes are zonular/nuclear pulverulent type with powdery dust like opacities. However, the phenotype balloon-like cataract with Y-sutural opacities linked with p.P88Q substitution observed in present family had no pulverized dust like opacities in the lens. The feathery opacities in between the Y-sutural opacities and three riders at the perimetry of the opaque fetal nucleus are very much prominent in the affected lenses in the present family.