Definition: The skeletal dysplasia cartilage-hair hypoplasia syndrome (CHH) combines metaphyseal dysplasia with short limb dwarfism, fine, sparse and blond hair, transient macrocytic anaemia and immunodeficiency. Hirschsprung disease is associated in approximately 10% of the cases.
Interestingly, Hirschsprung disease has been reported in the Holmgren-Connor syndrome (MIM 211120) which may be allelic to CHH.
This syndrome was first described in the Old Order Amish community.
Associations
Hirschsprung disease (12407544)
Etiology
The gene RMRP has been mapped to chromosome 9p13.
germline mutations in the RMRP gene (MIM.157660)