Alternative titles; symbols
SNOMEDCT: 48449000;
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
Gene/Locus |
Gene/Locus MIM number |
|---|---|---|---|---|---|---|
| 3q26.32 | Macrodactyly, somatic | 155500 | 3 | PIK3CA | 171834 |
A number sign (#) is used with this entry because of evidence that macrodactyly can be caused by somatic mutation in the PIK3CA (171834) gene on chromosome 3q26.
Macrodactyly is a congenital anomaly characterized by fibrofatty tissue enlargement and bony overgrowth in affected digits with resultant loss of function. Macrodactyly affects a 'nerve territory,' and the individual peripheral nerve is both enlarged and elongated (summary by Rios et al., 2013).
One or 2 fingers are grotesquely enlarged. Barsky (1967) and others found no report of familial occurrence. Lacombe and Battin (1996) described 2 children diagnosed at birth as having isolated macrodactyly. Follow-up examination showed development of hemihypertrophy and other findings suggesting Proteus syndrome (176920).
In 6 patients with macrodactyly, Rios et al. (2013) identified 4 different somatic mutations (e.g., 171834.0022) in the PIK3CA gene in affected tissue.
Barsky, A. J. Macrodactyly. J. Bone Joint Surg. Am. 49: 1255-1266, 1967. [PubMed: 4293291]
Lacombe, D., Battin, J. Isolated macrodactyly and Proteus syndrome. (Letter) Clin. Dysmorph. 5: 255-257, 1996. [PubMed: 8818455]
Rechnagel, K. Megalodactylism. Report of 7 cases. Acta Orthop. Scand. 38: 57-66, 1967. [PubMed: 6035453] [Full Text: https://doi.org/10.3109/17453676708989619]
Rios, J. J., Paria, N., Burns, D. K., Israel, B. A., Cornelia, R., Wise, C. A., Ezaki, M. Somatic gain-of-function mutations in PIK3CA in patients with macrodactyly. Hum. Molec. Genet. 22: 444-451, 2013. [PubMed: 23100325] [Full Text: https://doi.org/10.1093/hmg/dds440]