DGM (Dutch-German Mennonite)

Inheritance: X-linked
Genes: PQBP1

X-linked mental retardation
Renpenning type

Mental retardation
Small testes
Short stature

Renpenning Syndrome 1

Clinical Characteristics

General description (for patients):

Males only are affected in this disorder which causes mental slowness, and delayed walking and motor skills, including speech.  The head circumference is low normal and they frequently have a short stature.  The testes are small.  The ears may appear abnormally large and are prominently cupped.  This condition seems to be stable and there is no mental deterioration as children grow.

Medical description:  

This is a male-limited disorder that follows a classic X-linked inheritance pattern of inheritance. Motor skills such as walking and talking are delayed but there does not seem to be any deterioration.  Mental retardation is mild and non-progressive.  Short stature, mild microcephaly and small testes are usually present.  Other uncommon features are seizures, iris colobomas, and perhaps cupped ears.


This is an X-linked disorder due to a mutation located on the X chromosome (Xp11.23).  It is, of course, limited to males with transmission through the female.  A large Canadian Mennonite kinship with multiple affected males has been described. The mutation occurs in exon 5 of the PQBP1 gene and consists of a C insertion (c.641 insC) causing a frameshift and a premature stop codon.


No treatment is available.


Normal longevity but lifelong, apparently non-progressive mental retardation.

Ancillary treatments and support:

General care giving.  The mild nature of the mental deficit may allow some to attend special education classes.

Specialists and specialty centers:

Neurologist, Pediatrician.


Renpenning, H. J., Gerrard, J. W., Zaleski, W. A., and Tabata, T.:  Familial sex-linked mental retardation. Canad. Med. Assoc. J. 87: 954-956, 1962.  PubMed ID: 13981686

Lenski, C., Abidi, F., Meindl, A., Gibson, A., Platzer, M., Kooy, R. F., Lubs, H. A., Stevenson, R. E., Ramser, J., and Schwartz, C. E. :  Novel truncating mutations in the polyglutamine tract binding protein 1 gene (PQBP1) cause Renpenning syndrome and X-linked mental retardation in another family with microcephaly. (Letter) Am. J. Hum. Genet. 74: 777-780, 2004.  PubMed ID: 1502469