(Hypertrichosis-small stature-facial dysmorphism-developmental delay syndrome)
Prevalence estimated at 1/25,000 to 40,000.
Dysmorphic syndrome. De novo mutation or autosomal dominant transmission of an heterozygous mutation of the MLL or KNMT2A gene (11q23.3) that combines:
- in early childhood: hypotonia and feeding difficulties
- a short stature,
- ulnar hypertrichosis (hypertrichosis cubiti or hairy elbows),
- a facial dysmorphim: hypertelorism, telecanthus, long eyelashes, wide eyebrows, narrow and downslanting palpebral fissures, wide nose, long philtrum
- developmental delay with light to mild intellectual deficit
Sometimes: muscle hypotonia, persistent ductus arteriosus, small hands and feet, sometimes abnormalities of the cervical vertebrae (Chiari malformation), hypertrichosis of the back, behavioral disorders (autistic traits or hyperactivity with attention deficit disorder) and convulsions may also be observed.
Anesthetic implications:
check mobility of cervical spine
References :
- Schaeffer E, Morin G.
Protocole National de Diagnostic et de Soins (PNDS) Syndrome de Wiedemann-Steiner. 2022.
https://www.has-sante.fr/upload/docs/application/pdf/2022-11/synthese_mg_syndrome_de_wiedemann_steiner_wss.pdf
Updated: June 2025