PTPRF is disrupted in a patient with syndromic amastia

The presence of mammary glands distinguishes mammals from other organisms. Despite significant advances in defining the signaling pathways responsible for mammary gland development in mice, our understanding of human mammary gland development remains rudimentary. Here, we identified a woman with bilateral amastia, ectodermal dysplasia and unilateral renal agenesis. She was found to have a chromosomal balanced translocation, 46,XX,t(1;20)(p34.1;q13.13). In addition to characterization of her clinical and cytogenetic features, we successfully identified the interrupted gene and studied its consequences.

Characterization of the breakpoints was performed by molecular cytogenetic techniques. The interrupted gene was further analyzed using quantitative real-time PCR and western blotting. Mutation analysis and high-density SNP array were carried out in order to find a pathogenic mutation. Allele segregations were obtained by haplotype analysis.

We enabled to identify its breakpoint on chromosome 1 interrupting the protein tyrosine receptor type F gene (PTPRF). While the patient's mother and sisters also harbored the translocated chromosome, their non-translocated chromosomes 1 were different from that of the patient. Although a definite pathogenic mutation on the paternal allele could not be identified, PTPRF's RNA and protein of the patient were significantly less than those of her unaffected family members.

Although ptprf has been shown to involve in murine mammary gland development, no evidence has incorporated PTPRF in human organ development. We, for the first time, demonstrated the possible association of PTPRF with syndromic amastia, making it a prime candidate to investigate for its spatial and temporal roles in human breast development.