Mutations in ATP6V1B2, which encodes the B2 subunit of the vacuolar H + ATPase have previously been associated with Zimmermann-Laband syndrome 2 (ZLS2) and deafness-onychodystrophy (DDOD) syndrome.
Sequence analysis of the coding regions of keratin KRTHB5 gene, previously associated with a distinct clinical form of hair-nail dysplasia, revealed normal coding regions.
Here, we present exome sequencing and analysis of four generations of a family with a dominantly inherited Nail-Patella-like disorder (nail dysplasia with some features of Nail-Patella syndrome) who tested negative forLMX1B mutation.
Nail-patella syndrome (NPS) is an autosomal dominant disorder caused by mutations in the LMX1B gene and is characterized by nail dysplasia, skeletal abnormalities, and nephropathy.
In this study, in situ hybridizations of Lmx1b on murine limb sections reveal strong expression in dorsal mesenchymal tissues (precursors of muscle, tendons, joints and patella) and, interestingly, also in anterior structures of the limb, explaining the anterior to posterior gradient of joint and nail dysplasia observed in NPS patients.
Few case reports have identified mutations in the Frizzled 6 (<i>FZD6</i>) gene in families presenting with abnormal nails consistent with Non-Syndromic Congenital Nail Dysplasia.
The molecular mechanism of nail (and claw) development is largely unknown, but we have recently identified a Wnt receptor gene, Frizzled6 (Fzd6), that is mutated in a human autosomal-recessive nail dysplasia.