Hyperechogenic kidneys and polyhydramnios associated with HNF1B gene mutation.
HNF1B mutation is the leading cause of isolated hyperechogenic fetal kidneys with normal or moderately large size. Although most cases have normal amniotic fluid volume, some cases present with early oligohydramnios and renal failure associated with high perinatal mortality.



Here we report on seven fetuses from six unrelated families, carrying an HNF1B mutation, and presenting with polyhydramnios during the second or third trimester of pregnancy. Polyhydramnios was transitory in two cases. None of the mothers was presenting gestational diabetes. Bilateral hyperechogenic kidneys with size between -2.5 and +2 SD was the most common renal phenotype at prenatal US. Two patients were born prematurely at 28 and 32 weeks of gestation, respectively. Both presented high urine output the first days of life with urinary salt and potassium loss requiring hydro-electrolytic compensation. All mutations were large deletions removing the whole HNF1B gene.



In the absence of maternal diabetes, HNF1B mutation can be associated with polyhydramnios, probably due to fetal polyuria. Thus, HNF1B mutation represents a differential diagnosis of polyhydramnios associated with hyperechogenic (and sometimes enlarged) kidneys.
Service de Néphrologie Pédiatrique, Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Hôpital Necker-Enfants Malades, Assistance Publique- Hôpitaux de Paris, 149 rue de Sèvres, Paris Cedex 15, 75743, France.
Leire
L
Gondra
Service de Néphrologie Pédiatrique, Centre de Référence du Sud Ouest des Maladies Rénales Rares (SORARE), Hôpital Purpan, Toulouse, France.|Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Institute of Cardiovascular and Metabolic Diseases, Toulouse, France.|Université de Toulouse III Paul Sabatier, Toulouse, France.
Stéphane
S
Décramer
Obstetrics and Foetal Medicine Department, Necker-Enfants-Malades Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Descartes-Sorbonne Paris Cité, Paris, France.
Gihad E
GE
Chalouhi
Biochimie-Hormonologie, Hôpital Robert Debré, Assistance Publique-Hôpitaux de Paris, Paris, France.
Françoise
F
Muller
Service de Néphrologie Pédiatrique, Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Hôpital Necker-Enfants Malades, Assistance Publique- Hôpitaux de Paris, 149 rue de Sèvres, Paris Cedex 15, 75743, France.|Université Paris Descartes-Sorbonne Paris Cité, Paris, France.
Rémi
R
Salomon
Service de Néphrologie Pédiatrique, Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Hôpital Necker-Enfants Malades, Assistance Publique- Hôpitaux de Paris, 149 rue de Sèvres, Paris Cedex 15, 75743, France. laurence.heidet@aphp.fr.
Laurence
L
Heidet
D000328:Adult; D005260:Female; D005333:Fetus; D017353:Gene Deletion; D051539:Hepatocyte Nuclear Factor 1-beta / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007668:Kidney / Q000000981:diagnostic imaging*; D009154:Mutation; D010641:Phenotype; D006831:Polyhydramnios / Q000000981:diagnostic imaging* / Q000235:genetics*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D016216:Ultrasonography, Prenatal; D014563:Urodynamics; D001613:beta 2-Microglobulin / Q000097:blood
C496495:HNF1B protein, human; D001613:beta 2-Microglobulin; D051539:Hepatocyte Nuclear Factor 1-beta
Amniotic fluid; HNF1B; Hyperechogenic; Kidneys; Polyhydramnios