Hyperphosphatasia with mental retardation, brachytelephalangy, and a distinct facial gestalt: Delineation of a recognizable syndrome

Eur J Med Genet. 2010 Mar-Apr;53(2):85-8. doi: 10.1016/j.ejmg.2010.01.002. Epub 2010 Jan 18.


The association of mental retardation and persistent hyperphosphatasia has been described in rare instances. Because of parental consanguinity and sib recurrences autosomal recessive inheritance has been proposed. We report three sibs with a syndrome consisting of severe mental retardation, considerably elevated serum levels of alkaline phosphatase, hypoplastic terminal phalanges, and distinct facial features. Clinically and radiologically, shortness of distal phalanges could be demonstrated in all of them. Their particular facial appearance led us to two earlier reported familial cases with convincing clinical similarities. We suggest a specific clinical entity within the spectrum of patients with mental retardation and hyperphosphatasia, which is in particular characterized by a recognizable facial gestalt and brachytelephalangy.

Publication types

  • Case Reports

MeSH terms

  • Abnormalities, Multiple / diagnosis*
  • Abnormalities, Multiple / genetics*
  • Alkaline Phosphatase / genetics
  • Child, Preschool
  • Developmental Disabilities / genetics
  • Face / abnormalities*
  • Facies
  • Family Health
  • Female
  • Humans
  • Hyperphosphatemia / genetics*
  • Infant
  • Intellectual Disability / genetics*
  • Male
  • Rectum / abnormalities
  • Siblings
  • Syndrome


  • Alkaline Phosphatase