LRP4 site-specific variants in the third β-propeller domain causes congenital myasthenic syndrome type 17

Tariq Al Jabry, Nadia Al-Hashmi, Basem Abdelhadi, Almundher Al-Maawali
Sultan Qaboos University Hospital. Royal Hospital.
Oman

European Journal of Medical Genetics
Eir J Med Genet 2023;
DOI: 10.1016/j.ejmg.2023.104903

Abstract
LRP4 is expressed in many organs. It mediates SOST-dependent inhibition of bone formation and acts as an inhibitor of WNT signaling. It is also a postsynaptic end plate cell surface receptor at the neuromuscular junction and is central to its development, maintenance, and function. Pathogenic variants of LRP4 that specifically affect the canonical WNT signaling pathway are known to be associated with Cenani-Lenz syndactyly syndrome or the overlapping condition sclerosteosis. However, site-specific pathogenic variants of LRP4 have been associated with the congenital myasthenic syndrome (CMS) type 17 with no abnormal bone phenotype. Only two studies reported biallelic variants of LRP4 associated with CMS17 that presented during childhood. All three reported variants (NM_002334.4: p.Glu1233Ala, p.Glu1233Lys, or p.Arg1277His) are located within the 3′-edge of the third β-propeller domain of LRP4. We report on a patient with a biallelic variant of the LRP4 gene presenting with a severe and neonatal lethal phenotype; we also provide a literature review of the previously reported patients. A female neonate, born to healthy consanguineous parents, presented with severe hypotonia, congenital diaphragmatic hernia, pulmonary hypertension, and progressive hypoxemia. Two of her siblings presented with a similar condition in the past, and all three died shortly after birth. Clinical exome sequencing revealed homozygosity for the pathogenic variant NM_002334.4:c.3698A > C (p.[Glu1233Ala]).

Category
Class III. Pulmonary Hypertension Associated with Lung Hypoplasia
Genetic Factors Associated with Pulmonary Vascular Disease

Age Focus: Pediatric Pulmonary Vascular Disease

Fresh or Filed Publication: Filed (PHiled). Greater than 1-2 years since publication

Article Access
Free PDF File or Full Text Article Available Through PubMed or DOI: Yes

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