Table 1. Comparison of key features of 17q21.31 microdeletion syndrome, CFC syndrome and patients in this series.

(numerators are number of patients with the feature, denominators are the number of patients on whom the data was available)

	17q21.31 microdeletion (from Koolen et al, 2008)	CFC syndrome (from Armour & Allanson, 2008 [10])	Patient 1	Patient 2	Patient 3	Patient 4
Growth
Normal or high birthweight	16/22	37/38	yes	yes	no	yes
Feeding difficulties	common	19/30	yes	yes	mild	not known
Failure to thrive	not common	frequently severe	no	no	mild	not known
Normal OFC	21/22		yes	yes	yes	yes
Relative macrocephaly (OFC more than +1SD compared to height)	not characterised	17/33	yes	yes	yes	yes
Absolute macrocephaly (more than +3SD)	-	4/33	no	no	no	no
Short stature (below 3rd centile)	4/22	27/38	no	no	mild	severe
Neurological development
Developmental delay	22/22, variable degree	present; variable	severe	mild to moderate	mild to moderate	severe
Hypotonia	21/22	34/36	yes	yes	yes	not known
Seizures	11/22	18/37	no	no	no	no
Engaging or amiable personality	16/18	25/32	-	yes	yes	-
Heart
Pulmonary stenosis	-	14/33	no	yes	no	no
ASD or VSD	6/27	9/32	no	yes	no	no
Other cardiac defect		common	no	no	no	no
Skin and hair
Naevi	Present in some photos	28/37	yes	yes	yes	yes
Other skin pigmentary abnormality		very common, including café au lait patches and generalised hyperpigmentation	yes, generalised hyperpigmentation	-	yes, discrete area on abdomen (see figure)	yes, generalised hyperpigmentation
Keratosis pilaris/ hyperkeratosis/ ichthyosis dry skin	A few patients	20/28	yes	yes	yes	yes
Unusual hair (colour, texture, thickness)	13/22	34/38	yes	yes	yes	yes
Eyes
Strabismus	10/22	28/35	yes	no	no	no
Optic nerve hypoplasia	-	11/26	no	no	no	yes