Question: Which is the main abnormality that arises with Sox9 locus duplication?

Context:
Autosomal XX sex reversal caused by duplication of SOX9
Mutations of SOX9 leading to haploinsufficiency can cause campomelic dysplasia and XY sex reversal
We report here evidence supporting that SOX9 duplication can cause XX sex reversal
Fluorescent in situ hybridization (FISH) with a BAC clone containing the SOX9 gene demonstrated that the SOX9 gene is duplicated on the rearranged chromosome 17
SOX9 duplication linked to intersex in deer
Whole genome sequencing and quantitative real-time PCR analyses revealed a triple dose of the SOX9 gene, allowing insights into a new genetic defect in a wild animal
In addition, SOX9 duplication has been found to be a rare cause of 46,XX testicular DSD in humans
Extended pedigree with multiple cases of XX sex reversal in the absence of SRY and of a mutation at the SOX9 locus.
Together, these findings implicate a mutation at a sex-determining locus other than SRY and SOX9 as the cause for the XX sex reversal trait in this family.
Autosomal XX sex reversal caused by duplication of SOX9.
Sox9 duplications are a relevant cause of Sry-negative XX sex reversal dogs.
We report here evidence supporting that SOX9 duplication can cause XX sex reversal.
Mutations of SOX9 leading to haploinsufficiency can cause campomelic dysplasia and XY sex reversal.
Duplications of the locus DSS can lead to a failure of testicular development and a duplication of the region containing SOX9 has been implicated in XX sex reversal.
Extended pedigree with multiple cases of XX sex reversal in the absence of SRY and of a mutation at the SOX9 locus.
XX male sex reversal with genital abnormalities associated with a de novo SOX3 gene duplication.

Answer: The 46,XX testicular disorder of sex development (DSD), also known as 46,XX male syndrome, is a rare form of DSD and clinical phenotype shows complete sex reversal from female to male. A complex network of genes determines sex in mammals. Differentiation of testicular tissue in 46,XX individuals is seen either in XX males, the majority of them with SRY gene, or in individuals, usually SRY(-), with ovotesticular disorder of sex development (OT-DSD). SOX9 is one of the genes that play critical roles in male sexual differentiation.
Thus, SOX9 duplication is the most likely cause for the sex reversal in this case because it plays an important role in male sex determination and differentiation. The SRY-box 9 (SOX9) gene has several important functions during testis development and differentiation in males, and overexpression of SOX9 leads to the male development of 46,XX gonads in the absence of SRY.
Autosomal XX sex reversal caused by duplication of SOX9. Mutations of SOX9 leading to haploinsufficiency can cause campomelic dysplasia and XY sex reversal. We report here evidence supporting that SOX9 duplication can cause XX sex reversal. Fluorescent in situ hybridization (FISH) with a BAC clone containing the SOX9 gene demonstrated that the SOX9 gene is duplicated on the rearranged chromosome 17. SOX9 duplication linked to intersex in deer. 
SOX9 duplication can cause XX sex reversal.  SOX9 duplication has been found to be a rare cause of 46,XX testicular DSD in humans.
Mutations of SOX9 leading to haploinsufficiency can cause campomelic dysplasia and XY sex reversal. In addition, SOX9 duplication has been found to be a rare cause of 46,XX testicular DSD in humans.
Autosomal XX sex reversal caused by duplication of SOX9
Exact answer: Autosomal XX sex reversal