0000000000126231
AUTHOR
Maria Cristina Jakil
First-trimester screening for trisomy-21 using a simplified method to assess the presence or absence of the fetal nasal bone.
Objective To determine the benefit of including nasal bone assessment in addition to standard first-trimester markers (nuchal translucency, free beta human chorionic gonadotropin and pregnancy-associated plasma protein A) as a screening test for Down syndrome, using a strict criterion for classification of nasal bone absence. Study design Nasal bone assessment was conducted in 2411 patients with crown-rump length between 45 and 84 mm, including 15 patients with Down syndrome. A patient was considered to have an absent nasal bone only if there was no evidence of present nasal bone. Unlike other studies, nasal bone was classified as present when there was evidence of a thin echogenic line und…
A novel L1CAM mutation in a fetus detected by prenatal diagnosis
X-linked hydrocephalus is due to mutations in the L1 neuronal cell adhesion molecule (L1CAM) gene. L1 protein plays a key role in neurite outgrowth, axonal guidance, and pathfinding during the development of the nervous system. We report on a familial case diagnosed by prenatal ultrasonographic examination, with cerebellar hypoplasia, agenesis of the corpus callosum, and the bilateral overlapping of the second and third fingers of the hand. Sequencing of the L1CAM gene showed a novel missense mutation in exon 14: transition of a guanine to cytosine at position 1777 (c.1777G > C), which led to an amino acid change of alanine to proline at position 593 (Ala593Pro) in the sixth immunoglobulin …