Clinical and molecular findings in children with retinitis pigmentosa.

Purpose: To study the clinical and genetic features of a cohort of RP children.

Methods: We identified 46 RP patients with pathogenic or likely pathogenic mutations among 96 patients with a clinical diagnosis of retinitis pigmentosa. All of the patients underwent comprehensive clinical examinations and genetic testing. A retrospective study was conducted on 46 children with retinitis pigmentosa. The genetic and clinical characteristics of children with different genotypes were analyzed.

Results: Among the 46 children, 13 inherited X-linked gene mutations, including 9 RPGR and 4 RP2 mutations. There were 10 cases of autosomal dominant genes and 23 cases of autosomal recessive genes. XLRP accounted for a larger proportion of children, as observed in previous studies on RP. We found that RPGR genes were the most commonly mutated genes in RP children. The most frequently mutated gene was RPGR (9.3%), followed by RP2 (4.2%) and RPE65 (4.2%). Forty-six patients had mutations in 21 different genes, 19 of which were novel mutations.Most children with XLRP have a high degree of myopia, poor vision, and severe clinical symptoms. Frameshift mutations were more common in XLRP, followed by nonsense mutations. The onset of XLRP is relatively serious since childhood. Most children with ADRP have relatively good visual acuity and mild clinical symptoms, and missense mutations are common. The clinical manifestations of ARRP in children are more severe than those of ADRP in children but milder than those of XLRP in children, and missense mutations are common. The manifestations of RPE65 mutations are also severe and appear early.

Conclusions: Our results revealed that XLRP gene mutations were more common in children than in adults, as observed in previous studies on RP. The proportion of RP children with ADRP is relatively small. The new findings in our study polished the spectrum of novel mutations and the proportions of different genotypes in pediatric patients. The onset of XLRP occurred earlier. The genes with a high incidence in children were all relatively severe gene types of RP. This comprehensive database may provide essential information regarding the initial stage of RP.