Table 1.

Genetics of Syndromic and Nonsyndromic PRS

Clinical Presentation	Genetics (Gene Mutations)
A.Nonsyndromic PRS	SOX9 is the most frequently encountered gene mutation
B.Syndromic PRS*
1.Stickler syndrome type I (16% of cases)	COL2A1 mutations
2.Richieri-Costa–Pereira syndrome (8% of cases)	E1F4A3 biallelic expansion
3.Catel–Manzke syndrome (5.5% of cases)	TGDS mutations
4.Acampomelic and campomelic dysplasia; with or without sex reversal (4.7% of cases)	SOX9 mutations
5.TARP syndrome (3% of cases)	RBM10 mutations
6.Cerebro-costo-mandibular syndrome (2.7% of cases)	SNRPB mutations

*The syndrome is clinically diagnosed and genetically related in less than 50% of cases of syndromic PRS. In the remaining cases, there are either chromosomal abnormalities not related to a specific syndrome or no gene mutations could be identified.