Macrocephaly associated with the DICER1 syndrome

Germ-line mutations in DICER1 increase the risk of various tumors, including pleuropulmonary blastoma. Macrocephaly and symmetric overgrowth have been reported in some, but not all, patients with mosaic DICER1 RNase IIIb mutations. The prevalence of these features in individuals with constitutional germ-line DICER1 mutations is unknown.

We analyzed prospectively collected auxology data from 67 DICER1 mutation carriers and 43 family controls. We assessed differences between groups using an exact test for proportions and generalized estimating equations for continuous dependent variables.

Twenty-eight DICER1 mutation carriers (42%) were macrocephalic, and none had an occipitofrontal circumference (OFC) below the third centile, which significantly differed from family controls, of whom five were macrocephalic (12%) and two had OFC below the third centile (5%) (P < 0.001). DICER1 mutation carriers were taller than familial controls after controlling for gender (P = 0.048), but similar proportions of both groups were above the 97th centile of population norms. Head circumference remained increased after adjusting for differences in height.

For the first time, we establish macrocephaly as a common finding in the DICER1 syndrome. Like some other tumor-predisposition disorders, macrocephaly may be a useful, albeit a subtle, clinical clue to the DICER1 syndrome diagnosis.Genet Med advance online publication 21 July 2016Genetics in Medicine (2016); doi:10.1038/gim.2016.83.

Genetics in medicine : official journal of the American College of Medical Genetics. 2016 Jul 21 [Epub ahead of print]

Nicholas E Khan, Andrew J Bauer, Leslie Doros, Kris Ann P Schultz, Rosamma M Decastro, Laura A Harney, Ron G Kase, Ann G Carr, Anne K Harris, Gretchen M Williams, Louis P Dehner, Yoav H Messinger, Douglas R Stewart

Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA., Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA., Children's National Medical Center, Washington, DC, USA., Children's Hospitals and Clinics of Minnesota, Minneapolis, Minnesota, USA., Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA., Westat Inc., Rockville, Maryland, USA., Westat Inc., Rockville, Maryland, USA., Westat Inc., Rockville, Maryland, USA., Children's Hospitals and Clinics of Minnesota, Minneapolis, Minnesota, USA., Children's Hospitals and Clinics of Minnesota, Minneapolis, Minnesota, USA., Washington University, St. Louis, Missouri, USA., Children's Hospitals and Clinics of Minnesota, Minneapolis, Minnesota, USA., Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA.