Novel causative variants in patients with achromatopsia

ABSTRACT

Purpose: To report five novel genetic variants in seven unrelated consanguineous families with achromatopsia (ACHM).

Methods: Patients were examined with multimodal retinal imaging and full-field electroretinography (ffERG). Genetic testing was conducted using next-generation sequencing (NGS).

Results: Three novel homozygous variants were detected in CNGA3: a missense c.967G > C (p.Ala323Pro) variant was detected in exon 8 (one patient), a splice site variant c.101 + 1G > A in intron 2 (three patients), and a splice site variant c.395 + 1G > T in intron 4(one patient). Another two novel variants were found in PDE6C: a homozygous missense variant c.1899C > A (p.His633Gln) in exon 15 (one patient) and a homozygous splice site variant c.1072-1G > C in intron 7 (one patient). Mutation segregation assessment was possible in 3 of the 7 families. All patients had nonrecordable ffERG 30-Hz flicker responses, reduced single-flash cone responses but preserved rod responses. Patients presented with variable degrees of foveal outer retinal layer loss and variable patterns of foveal hyperautofluorescence.

Conclusions: These novel variants expand the genotypes associated with ACHM and may help in future therapy development for ACHM.

KEYWORDS:

• Achromatopsia
• CNGA3 variant
• cone dysfunction
• electroretinogram
• fundus autofluorescence
• PDE6C variant

Disclosure statement

All authors have no conflict of interests to declare.