METHODS: This case series study included 15 patients with clinical presentations, suggestive of achromatopsia, who underwent ophthalmological and systemic evaluations. Patients with typical achromatopsia phenotype underwent genetic evaluation using whole-exome testing.
RESULTS: All patients had nystagmus (n = 15) and 93.3% had photophobia (n = 14). In addition, all patients (n = 15) had poor VA. Hyperopia with astigmatism was observed in 93.3% (n = 14) and complete color blindness in 93.3% of the patients (n = 14). In the context of family history, both parents of all patients (n = 15) were genetic carriers, with a high consanguinity rate (82%, n = 9 families). Electroretinography showed cone dysfunction with normal rods in 66.7% (n = 10) and both cone-rod dysfunction in 33.3% (n = 5) patients. Regarding the genotypic features, 93% of patients had variants in CNGA3 (n = 14) categorized as pathogenic Class 1 (86.7%, n = 13). Further, 66.7% (n = 10) of patients also harbored the c.661C>T DNA variant. Further, the patients were homozygous for these mutations. Three other variants were also identified: c.1768G>A (13.3%, n = 2), c.830G>A (6.6%, n = 1), and c. 822G >T (6.6%, n = 1).
CONCLUSIONS: Consanguinity and belonging to the same tribe are major risk factors for disease inheritance. The most common genotype was CNGA3 with the c.661C>T DNA variant. We recommend raising awareness among families and providing genetic counseling for this highly debilitating disease.
方法:本病例系列研究包括15例患者的临床表现,暗示着色盲,他们接受了眼科和系统评估。具有典型色盲表型的患者使用全外显子组测试进行遗传评估。
结果:所有患者有眼球震颤(n=15),93.3%有畏光(n=14)。此外,所有患者(n=15)的VA均较差。在93.3%(n=14)的患者中观察到有散光的远视,在93.3%的患者中观察到完全色盲(n=14)。在家族史的背景下,所有患者的父母(n=15)都是遗传携带者,血缘率高(82%,n=9个家庭)。视网膜电描记术在66.7%(n=10)的患者中显示出视锥功能障碍,在33.3%(n=5)的患者中显示出视锥功能障碍。关于基因型特征,93%的患者有CNGA3变异(n=14)分类为致病性1类(86.7%,n=13)。Further,66.7%(n=10)的患者也携带c.661C>TDNA变异。Further,这些突变的患者是纯合子.还鉴定出其他三个变体:c.1768G>A(13.3%,n=2),c.830G>A(6.6%,n=1),c。822G>T(6.6%,n=1)。
结论:血缘关系和属于同一部落是疾病遗传的主要危险因素。最常见的基因型是具有c.661C>TDNA变异的CNGA3。我们建议提高家庭的认识,并为这种高度衰弱的疾病提供遗传咨询。