Variants of LRP2, encoding a multifunctional cell-surface endocytic receptor, associated with hearing loss and retinal dystrophy.

Hereditary deafness and retinal dystrophy are each genetically heterogenous and clinically variable. Three small unrelated families segregating the combination of deafness and retinal dystrophy were studied by exome sequencing (ES). The proband of Family 1 was found to be compound heterozygous for NM_004525.3: LRP2: c.5005A > G, p.(Asn1669Asp) and c.149C > G, p.(Thr50Ser). In Family 2, two sisters were found to be compound heterozygous for LRP2 variants, p.(Tyr3933Cys) and an experimentally confirmed c.7715 + 3A > T consensus splice-altering variant. In Family 3, the proband is compound heterozygous for a consensus donor splice site variant LRP2: c.8452_8452 + 1del and p.(Cys3150Tyr). In mouse cochlea, Lrp2 is expressed abundantly in the stria vascularis marginal cells demonstrated by smFISH, single-cell and single-nucleus RNAseq, suggesting that a deficiency of LRP2 may compromise the endocochlear potential, which is required for hearing. LRP2 variants have been associated with Donnai-Barrow syndrome and other multisystem pleiotropic phenotypes different from the phenotypes of the four cases reported herein. Our data expand the phenotypic spectrum associated with pathogenic variants in LRP2 warranting their consideration in individuals with a combination of hereditary hearing loss and retinal dystrophy.

Open communication of Duchenne muscular dystrophy facilitates disclosure process by parents to unaffected siblings.

Duchenne muscular dystrophy (DMD) is a progressive childhood onset neuromuscular disease with no known cure. There is extensive literature about the impact of a diagnosis on the psychosocial well-being of unaffected siblings, with a need for additional research to provide information about optimal ways to disclose this information to unaffected children. We sought to explore the parental experiences of disclosing a sibling's diagnosis of DMD to unaffected children who were age 8-17 years old either at the time of their sibling's diagnosis or presently. Parents were recruited through Maryland Muscular Dystrophy Association, Parent Project Muscular Dystrophy, and Cincinnati Children's Hospital Medical Center Neuromuscular Center. An interview guide, rooted in family communication, was created to incorporate themes and topics found in literature specific to DMD and disclosure to unaffected siblings. We qualitatively explored these experiences through semi-structured interviews and performed thematic analysis using a coding system to identify overarching themes and subthemes. Several main themes regarding challenges to the disclosure process emerged. We identified the following themes in procedural aspects of disclosure: lack of provider support, importance of the DMD community, and open and gradual timeline of disclosure. Under emotional experiences, we identified these themes: overwhelming nature, elements of surprise disclosure, and balancing parental and sibling needs. Most questions from unaffected siblings related to procedural elements of care such as treatments and equipment. Additional unanticipated themes emerged that may contribute to the knowledge of family culture surrounding DMD: the complex role of Facebook as a family resource, deferring carrier testing for siblings, and inclusion of DMD in school projects. While the process of disclosure is complicated by a variety of factors such as lack of provider support and overwhelming emotional burden, families highlight the importance of open communication in discussion with unaffected children.