Orphanet: X linked intellectual disability, Siderius type

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X-linked intellectual disability, Siderius type

Disease definition

X-linked intellectual disability, Siderius type is characterised by mild to borderline intellectual deficit associated with cleft lip/palate. Preaxial polydactyly, large hands and cryptorchidism are sometimes present. The syndrome has been described in seven boys from two families. Transmission is X-linked and the syndrome is caused by mutations in the PHF8 gene, localised to the p11.21 region of the X chromosome.


Classification level: Disorder
  • Synonym(s): -
  • Prevalence: <1 / 1 000 000
  • Inheritance: X-linked recessive 
  • Age of onset: Infancy, Neonatal
  • ICD-10: Q87.8
  • OMIM: 300263
  • UMLS: C1846055
  • MeSH: C537333
  • GARD: 9704
  • MedDRA: -
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