The<unk>  or microcephalic primordial dwarfism is a congenital nanosomic disorder supposed to be caused by defects of genes on chromosome 3 and 18. It is characterized by intrauterine growth retardation, along with growth & developmental delays even after birth. There are characteristic bird like facies with a beak like nose, microcephalic head, micrognathia(small head) and malformed ears.  One form of<unk>  can be caused by mutation in the gene encoding ataxia-telangiectasia and RAD3-related protein ATR which maps to chromosome 3q22.1-q24.
Seckel syndrome
Meckel syndrome
Zimmerman-Laband syndrome
Crigler-Najjar syndrome
Scheuermann's disease
Hartnup Disease
Klüver-Bucy syndrome
Mirizzi's syndrome