Novel CRB1 pathogenic variant in Chuuk families with Leber congenital amaurosis.

The purpose of this article is to determine the cause of Leber congenital amaurosis (LCA) in Chuuk state, Federated States of Micronesia (FSM). In this prospective observational case series, five patients with early-onset vision loss were examined in Chuuk state, FSM, during an ocular genetics visit to study the elevated incidence of microphthalmia. Because of their low vision these patients were incorrectly assumed to have microphthalmia. A complete ophthalmological exam established a clinical diagnosis of LCA. Candidate gene exons were sequenced with a targeted retinal dystrophy panel. Five subjects in three related families were diagnosed with LCA. All five were from Tonoas Island, within the Chuuk Lagoon, with ages ranging from 6 months to 16 years. DNA sequencing of affected individuals revealed a homozygous CRB1 NM_201253.3:c.3134del pathogenic variant, which was heterozygous in their parents. CRB1 genotypes were confirmed by a PCR restriction assay. We report identification of a founder pathogenic variant in CRB1 responsible for autosomal recessive LCA in this isolated community. This discovery will lead to appropriate recurrence risk counseling.

Blood lead levels and risk factors for lead poisoning in children and caregivers in Chuuk State, Micronesia.

Lead poisoning is a preventable environmental disease. Children and developing fetuses are especially vulnerable; even low blood lead levels (BLLs) are linked with learning and behavioral problems. We assessed children's and their caregivers' BLLs and risk factors for lead exposure in Chuuk State, Federated States of Micronesia. Children aged 2-6 years were randomly selected within 20 randomly selected villages. Children and caregivers provided venous blood, and caregivers offered information about possible risk factors for lead exposure. Mean BLLs were 39 microg/l for children and 16 microg/l for caregivers. Children with BLLs of > or = 100 microg/l (elevated) were 22.9 (95% CI: 4.5-116.0) times more likely to have a caregiver with an elevated BLL, 6.2 (95% CI: 1.4-27.3) times more likely to live on an outer island, and 3.4 (95% CI: 1.7-6.9) times more likely to have a family member who made lead fishing weights than did other children even after controlling for age and sex. For children, 61% of elevated BLLs could be attributed to making fishing weights. Caregivers with elevated BLLs were 5.9 (95% CI: 1.5-23.7) times more likely to live in a household that melted batteries than other caregivers even after controlling for age and education. For caregivers, 37% of the elevated BLLs could be attributed to melting batteries. The association of elevated BLLs in children and their caregiver suggests a common environmental exposure. Melting batteries to make fishing sinkers is a preventable source of lead exposure for children and their caregivers in Chuuk. Published by Elsevier GmbH.