DGM (Dutch-German Mennonites)

Inheritance: autosomal recessive
Genes: DNA helicase RecQ protein-like-3


Growth deficiency
Skin pigmentation
Chromosomal instability

Bloom Syndrome

Clinical Characteristics

General description (for patients):  

Bloom syndrome causes growth deficiency both before and after birth.  Low birth weight and failure to thrive are common.  It is associated with abnormal and sun-sensitive skin pigmentation and ‘spidery’ blood vessels.  Chromosomes are fragile in this condition with frequent fragmentation and an associated increased risk of malignancies (see also ataxia-telangiectasia).  Children are at considerable risk of leukemia.

Medical description:  

Bloom syndrome confers an increased risk of malignancy possibly as a consequence of non-specific chromosomal fragility.  Pre- and postnatal growth deficiency, diabetes mellitus, and sun-sensitive hypo- and hyperpigmented skin with telangiectases are also features.  Leukopenic leukemia is an especially serious risk in children and is difficult to treat.


This is an autosomal recessive disorder resulting from mutations in the gene encoding DNA helicase RecQ protein-like-3 leading to structural alterations.  It is found predominantly in Ashkenazi Jews.  However an identical ligase I structural defect was found in a single Canadian Mennonite sibship with two children, a 3 year old and a 14 month old, born to a consanguineous couple.  The youngest had a Wilm’s tumor.


No effective treatment has been found.


Survival into adult years is the exception as the result of malignancies.

Ancillary treatments and support:

Avoidance of sun exposure, treatment of malignancies.

Specialists and specialty centers:  

Pediatrician, Hematologist, Oncologist.


Weksberg, R., Smith, C., Anson-Cartwright, L., and Maloney, K.:  Bloom syndrome: a single complementation group defines patients of diverse ethnic origin.  Am. J. Hum. Genet. 42: 816-824, 1988. PubMed ID: 3163468

Willis, A.E., Weksberg, R., Tomlinson, S., and Lindahl, T.:  Structural alterations of DNA ligase I in Bloom syndrome.  Proc. Nat. Acad. Sci. 84: 8016-8020, 1987.  PubMed ID: 3479778

Ellis, N.A., and German, J.:  Molecular genetics of Bloom’s syndrome.  Hum. Molec. Genet. 5: 1457-1463. PubMed ID: 8875252


Bloom's Syndrome Foundation