BBS10 mutations are common in 'Meckel'-type cystic kidneys

Area of Science:

• Genetics
• Developmental Biology
• Medical Diagnostics

Background:

• Bardet-Biedl syndrome (BBS) is a genetic disorder with varied symptoms including retinal dystrophy, obesity, and kidney abnormalities.
• It follows autosomal recessive inheritance, with 14 genes identified, and BBS10 mutations accounting for 20% of cases.
• Digenic inheritance is also observed in some families.

Observation:

• The BBS10 gene was sequenced in 20 fetuses and one child with antenatal diagnoses of renal anomalies and polydactyly.
• This investigation was prompted by prior findings of BBS gene mutations in Meckel-like fetuses and the high prevalence of BBS10 mutations.

Findings:

• Recessive mutations in the BBS10 gene were found in five cases (four fetuses, one child).
• One case presented with situs ambiguus, a rare BBS feature.
• The child also had a BBS6 mutation, supporting multigenic inheritance.

Implications:

• Bardet-Biedl syndrome is likely underdiagnosed antenatally, especially in fetuses with severe cystic kidneys.
• Systematic genetic screening for BBS is recommended in such cases.
• The study highlights the high frequency of BBS10 mutations, including in lethal BBS forms.