Absence of PITX3 mutation in a Tunisian family with congenital cataract and mental retardation.
OBJECTIVE
The PITX3 (pituitary homeobox 3) gene encodes for a homeobox bicoid-like transcription factor. When one allele is mutated, it leads to dominant cataract and anterior segment mesenchymal dysgenesis in humans. When both copies are mutated, homozygous mutation contributes to microphtalmia with brain malformations. In the current study, a family with autosomal recessive congenital cataract (ARCC) associated with mental retardation (MR) was examined to identify PITX3 mutations.


METHODS
Sequencing of the PITX3 gene was performed on two affected and three unaffected members of the studied Tunisian family. The results were analyzed with Sequencing Analysis 5.2 and SeqScape.


RESULTS
No mutation in the four exons of PITX3 was revealed. Two substitution polymorphisms, c.439C>T and c.930C>A, were detected in exons 3 and 4, respectively. These alterations did not segregate with the disease.


CONCLUSIONS
Although PITX3 was shown to be essential to normal embryonic eye and brain development in vertebrates, we report the absence of PITX3 mutations in a family presenting congenital cataract and mental retardation.
Chograni
Manèl
M
Faculté de Médecine de Tunis, Laboratoire Génétique Humaine, Tunis, Tunisia.
Chaabouni
Myriam
M
Chelly
Imen
I
Helayem
Mohamed Bechir
MB
Chaabouni-Bouhamed
Habiba
H
D000293:Adolescent; D000328:Adult; D002386:Cataract / Q000150:complications / Q000151:congenital* / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D005190:Family; D005260:Female; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008607:Intellectual Disability / Q000150:complications* / Q000235:genetics*; D008297:Male; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D014157:Transcription Factors / Q000235:genetics*; D014416:Tunisia; D055815:Young Adult
D018398:Homeodomain Proteins; D014157:Transcription Factors; C433629:homeobox protein PITX3