[MIM 301 039]

X-linked recessive transmission of a mutation of the NKAP gene (Xq24). Particular form of X-linked mental retardation associated with a marfanoid habitus. Very close to the Lujan-Fryns syndrome.

Association of:

-        global developmental retardation

-        hypotonia

-        delayed speech

-        tall stature with marfanoid appearance

-        facial dysmorphism: elongated face, midface hypoplasia, open mouth, short philtrum, large ears

More rarely:

-        cardiac malformation: mitral regurgitation, ASD, VSD, dilated ascending aorta

-        pectus excavatum or carinatum

-        scoliosis

-        obesity

-        cryptorchidism

-        behavioural disorders: hyperactivity with attention deficit, aggressivity

Anesthetic implications:

cardiac and aortic echography; communication difficulties; obesity

References:

-        Fiordaliso S K, Iwata-Otsubo A, Ritter A L,1 Quesnel-Vallie M, Fujiki K, Nishi E, Hancarova M et al. 
Missense Mutations in NKAP cause a disorder of transcriptional regulation characterized by Marfanoid habitus and cognitive impairment.
Am J Human Genet 2019;105: 987-95

Updated: August 2020