Akademik Veri Yönetim Sistemi
6.ULUSLARARASI ERCİYES TIP TIBBİ GENETİK KONGRESİ, Kayseri, Türkiye, 16 - 18 Eylül 2021, cilt.33, sa.1, ss.37
The L1CAM gene is located on chromosome Xq28 and is expressed primarily in the nervous system, where it plays important roles in neuronal
development, including the guidance of neurite outgrowth, neuronal cell migration, myelination, neuronal cell survival, and long-term
potentiation. L1 syndrome is an X-linked recessive rare genetic disorder. L1 disease is a group of overlapping clinical phenotypes including Xlinked hydrocephalus, HSAS (hydrocephalus due to stenosis of aqueduct of Sylvius), MASA (mental retardation, aphasia, shuffling gait, and
adducted thumbs), and CRASH (corpus callosum hypoplasia, retardation, adducted thumbs, spastic paraplegia, and hydrocephalus)
syndromes.
A two-day-old male patient with hydrocephalus was referred from the Neonatology Department. Hydrocephalus was also present in prenatal
ultrasonography. His parents were healthy and were not consanguineous. He also had a 2-year-old brother with hydrocephalus. In physical
examination, he had adducted thumbs. Cranial MRI examination revealed agenesis of the corpus callosum. Afterward, we also evaluated his
brother and detected the same clinical and imaging findings. A multigene panel was performed on two siblings with a preliminary diagnosis
of the L1 syndrome. Molecular analysis revealed a novel hemizygous frameshift variant (c.539dupA; p.Gln181Alafs*46) in L1CAM in both
patients. This variant was confirmed by Sanger sequencing. The mother was found to have the same variant in the heterozygous state.
In this study, we contribute to the molecular spectrum of L1 syndrome by reporting a novel variant in the L1CAM gene. We emphasize the
importance of revealing the molecular pathology in the etiology of hydrocephalus in providing accurate genetic counseling to families.