49,XYYYY syndrome
MONDO:002047049,XYYYY is a rare Y chromosome number anomaly with a variable phenotype mainly characterized by moderate to severe intellectual disability, speech delay, hypotonia, and mild dysmorphic features, including facial asymmetry, hypertelorism, bilateral low set 'lop' ears, and micrognatia. Skeletal abnormalities (such as skull deformities, radioulnar synostosis, elbow flexion, clinodactyly, brachydactyly) and behavourial problems have also been associated with this condition. Genitalia are normal at birth, although hypogonadism and azoospermia has been reported in adults.
6 clinical trials for this condition and its sub-types, 0 tagged with 49,XYYYY syndrome itself.
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New study aims to unlock mysteries of sex chromosome disorders in children
Knowledge-focused By invitation onlyThis study follows 300 fetuses and children with sex chromosome disorders to track their growth, organ development, and overall health. Researchers will also look at genetic and gut microbiome factors. The goal is to better understand how these conditions affect children over tim…
Sponsor: University of Aarhus • Aim: Knowledge-focused
Last updated Jun 27, 2026 08:11 UTC
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Scientists probe genetic secrets of lost fetuses to unravel sex chromosome mysteries
Knowledge-focused By invitation onlyThis study looks at fetuses with sex chromosome disorders (like extra or missing X or Y chromosomes) that were either miscarried or electively aborted. Researchers will analyze the placenta and fetal tissues to see how the chromosome changes affect gene activity and development. …
Sponsor: University of Aarhus • Aim: Knowledge-focused
Last updated Jun 27, 2026 08:09 UTC