McKusick-Kaufman syndrome (MKS, OMIM #236700) is a rare syndrome inherited in an 
autosomal recessive pattern with a phenotypic triad comprising hydrometrocolpos 
(HMC), postaxial polydactyly (PAP), and congenital cardiac disease (CHD). The 
syndrome is caused by mutations in the MKKS gene mapped onto chromosome 20p12 
between D20S162 and D20S894 markers. Mutations in the same gene causes 
Bardet-Biedl-6 syndrome (BBS-6, OMIM #209900) inherited in an autosomal 
recessive pattern. BBS-6 comprises retinitis pigmentosa, polydactyly, obesity, 
mental retardation, renal and genital anomalies. HMC, CHD, and PAP defects can 
also occur in BBS-6, and there is a significant clinical overlap between MKS and 
BBS-6 in childhood. We describe a new borderline case of MKS and BBS syndrome 
and suggest insights for understanding correlation between MKKS gene mutations 
and clinical phenotype. Here, we report the results of molecular analysis of 
MKKS in a female proband born in an Italian nonconsanguineous healthy family 
that presents HMC and PAP. The mutational screening revealed the presence of two 
different heterozygous missense variants (p.242A>S in exon 3, p.339 I>V in exon 
4) in the MKKS gene, and a nucleotide variation in 5'UTR region in exon 2 (-417 
A>C).