Table 2.

Disorders to Consider in the Differential Diagnosis of KBG Syndrome

DiffDx DisorderGene(s)MOIClinical Features of the DiffDx Disorder
Overlapping w/KBG syndromeDistinguishing from KBG syndrome
Cornelia de Lange syndrome NIPBL
SMC1A
HDAC8
SMC3
RAD21 		AD
XL
  • Facial features
  • DD
  • Growth restriction
  • Hearing loss
  • Cryptorchidism
Typically:
  • Head circumference small
  • ID more severe
Silver-Russell syndrome See footnote 1.See footnote 1.
  • Facial features
  • DD
  • Growth restriction
  • Cryptorchidism
  • IUGR
  • Limb/facial asymmetry
Aarskog-Scott syndrome
(OMIM 305400)		 FGD1 XL
  • Short stature
  • Distinctive facial features
  • Macrodontia
  • Brachydactyly
  • Vertebral anomalies
  • Cryptorchidism
  • Cognitive ability normal in most
  • Shawl scrotum in males
Cohen syndrome VPS13B AR
  • Prominent central incisors
  • DD
  • Microcephaly
  • Obesity
  • Myopia
  • Choreoretinal dystrophy

AD = autosomal dominant; AR = autosomal recessive; DD = developmental delay; DiffDx = differential diagnosis; ID = intellectual disability; IUGR = intrauterine growth restriction; MOI = mode of inheritance; XL = X-linked

1.

Silver-Russell syndrome has multiple etiologies including: epigenetic changes that modify expression of genes in the imprinted region of chromosome 11p15.5, maternal UPD7, and (infrequently) autosomal dominant or autosomal recessive inheritance.

From: KBG Syndrome

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