Congenital disorders of glycosylation type I: a rare but new cause of hyperechoic kidneys in infants and children due to early microcystic changes.
BACKGROUND
There are numerous causes of bilateral hyperechoic kidneys. Congenital disorders of glycosylation (CDGs) are a rapidly growing family of inherited disorders due to defects in the synthesis of the glycans of glycoproteins or other glycoconjugates.


OBJECTIVE
To describe renal sonographic abnormalities in CDG type I in infants and children.


METHODS
A retrospective study of renal US in 12 infants and children: 8 CDG-Ia (6 multivisceral forms, 2 neurological forms), 2 CDG-Ib, and 2 CDG-Ix, with detailed functional renal tests in 6. Histology of the kidneys of one 35-week fetus with CDG-Ia was available.


RESULTS
Renal US was normal in the two children with the neurological form of CDG-Ia. All patients with the multivisceral form of CDG-Ia or with CDG-Ib showed increased cortical echogenicity, and/or abnormal pyramids (small +/- hyperechoic). The two patients with CDG-Ix showed predominant involvement of the medulla, with inverted corticomedullary differentiation in one. Kidney size was normal in all but two patients. The fetal kidneys exhibited diffuse microcysts arising from the distal tubules.


CONCLUSIONS
Hyperechoic kidneys are common in CDG-I patients, contrasting with grossly preserved renal function. The US pattern seems to differ slightly according to the type of CDG-I, and is consistent with microcystic changes of the renal parenchyma, which occur prenatally, and may be due to ciliary dysfunction secondary to altered glycosylation of tubular glycoproteins. CDG-I, which remains largely underdiagnosed at present, should be added to the causes of hyperechoic kidneys in children, especially in cases of multivisceral involvement, after ruling out other more frequent causes.
Hertz-Pannier
Lucie
L
Department of Paediatric Radiology, Hôpital Necker-Enfants Malades, 149 rue de Sèvres, 75743 Paris Cedex 15, France. lucie.hertz-pannier@nck.ap-hop-paris.fr
Déchaux
Michele
M
Sinico
Martine
M
Emond
Sophie
S
Cormier-Daire
Valerie
V
Saudubray
Jean-Marie
JM
Brunelle
Francis
F
Niaudet
Patrick
P
Seta
Nathalie
N
de Lonlay
Pascale
P
D002239:Carbohydrate Metabolism, Inborn Errors / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000235:genetics; D002675:Child, Preschool; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D005333:Fetus; D006031:Glycosylation; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007668:Kidney / Q000000981:diagnostic imaging* / Q000473:pathology; D052177:Kidney Diseases, Cystic / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000235:genetics; D008297:Male; D009154:Mutation; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal