Antenatal presentation of Bardet-Biedl syndrome may mimic Meckel syndrome.
Bardet-Biedl syndrome (BBS) is a multisystemic disorder characterized by postaxial polydactyly, progressive retinal dystrophy, obesity, hypogonadism, renal dysfunction, and learning difficulty. Other manifestations include diabetes mellitus, heart disease, hepatic fibrosis, and neurological features. The condition is genetically heterogeneous, and eight genes (BBS1-BBS8) have been identified to date. A mutation of the BBS1 gene on chromosome 11q13 is observed in 30%-40% of BBS cases. In addition, a complex triallelic inheritance has been established in this disorder--that is, in some families, three mutations at two BBS loci are necessary for the disease to be expressed. The clinical features of BBS that can be observed at birth are polydactyly, kidney anomaly, hepatic fibrosis, and genital and heart malformations. Interestingly, polydactyly, cystic kidneys, and liver anomalies (hepatic fibrosis with bile-duct proliferation) are also observed in Meckel syndrome, along with occipital encephalocele. Therefore, we decided to sequence the eight BBS genes in a series of 13 antenatal cases presenting with cystic kidneys and polydactyly and/or hepatic fibrosis but no encephalocele. These fetuses were mostly diagnosed as having Meckel or "Meckel-like" syndrome. In six cases, we identified a recessive mutation in a BBS gene (three in BBS2, two in BBS4, and one in BBS6). We found a heterozygous BBS6 mutation in three additional cases. No BBS1, BBS3, BBS5, BBS7, or BBS8 mutations were identified in our series. These results suggest that the antenatal presentation of BBS may mimic Meckel syndrome.
Karmous-Benailly
Houda
H
Département de Génétique et Unité INSERM U-393, Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.
Martinovic
Jelena
J
Gubler
Marie-Claire
MC
Sirot
Yoann
Y
Clech
Laure
L
Ozilou
Catherine
C
Auge
Joëlle
J
Brahimi
Nora
N
Etchevers
Heather
H
Detrait
Eric
E
Esculpavit
Chantal
C
Audollent
Sophie
S
Goudefroye
Géraldine
G
Gonzales
Marie
M
Tantau
Julia
J
Loget
Philippe
P
Joubert
Madeleine
M
Gaillard
Dominique
D
Jeanne-Pasquier
Corinne
C
Delezoide
Anne-Lise
AL
Peter
Marie-Odile
MO
Plessis
Ghislaine
G
Simon-Bouy
Brigitte
B
Dollfus
Hélène
H
Le Merrer
Martine
M
Munnich
Arnold
A
Encha-Razavi
Férechté
F
Vekemans
Michel
M
Attié-Bitach
Tania
T
D000015:Abnormalities, Multiple / Q000175:diagnosis* / Q000235:genetics*; D020788:Bardet-Biedl Syndrome / Q000175:diagnosis* / Q000235:genetics*; D001483:Base Sequence; D004252:DNA Mutational Analysis; D003937:Diagnosis, Differential; D004677:Encephalocele / Q000175:diagnosis / Q000235:genetics; D005260:Female; D005333:Fetus / Q000473:pathology; D006801:Humans; D007231:Infant, Newborn; D007668:Kidney / Q000002:abnormalities; D008099:Liver / Q000002:abnormalities; D008297:Male; D010375:Pedigree; D011247:Pregnancy; D011296:Prenatal Diagnosis; D013577:Syndrome