Clubfoot is a birth defect where one or both feet are rotated inward and downward. Congenital clubfoot, is the most common congenital malformation of the foot with an incidence of 1 per 1000 births. In approximately 50% of cases, clubfoot affects both feet, but it can present unilaterally causing one leg or foot to be shorter than the other. Most of the time, it is not associated with other problems. Without appropriate treatment, the foot deformity will persist and lead to pain and impaired ability to walk, which can have a dramatic impact on the quality of life.The exact cause is usually not identified. Both genetic and environmental factors are believed to be involved. There are two main types of congenital clubfoot: idiopathic (80% of cases) and secondary clubfoot (20% of cases). The idiopathic congenital clubfoot is a multifactorial condition that includes environmental, vascular, positional, and genetic factors. There appears to be hereditary component for this birth defect given that the risk of developing congenital clubfoot is 25% when a first-degree relative is affected. In addition, if one identical twin is affected, there is a 33% chance the other one will be as well. The underlying mechanism involves disruption of the muscles or connective tissue of the lower leg, leading to joint contracture. Other abnormalities are associated 20% of the time, with the most common being distal arthrogryposis and myelomeningocele.
The theory of fetal growth arrest was proposed by Von Volkmann in 1863, and has been verified by other authors since. According to this theory, intrinsic errors or environmental insults during gestation prevents the correction of a equinovarus to pronated foot. Other researchers hypothesize that clubfoot may derive from external insults during gestation. For example, a research study found an alarming high incidence of club foot and limb contractures associated with iatrogenic amniotic leakage cause by early amniocentesis between the 11th and 12th week of gestation.Intrinsic Factors

Chromosomal abnormalities found in 30% and 2% of complex clubfoot and isolated clubfoot respectively. These include trisomy 18, 13, 21, sex chromosome abnormalities, micro-deletions and duplications. Genetic Syndromes: Larsen, Gordon, Pierre-Robin, Meckel-Gruber, Roberts, Smith-Lemli-Opitz, TARP (Talipes equinovarus, Atrial septal defect, Robin sequence, Persistence of left superior vena cava). Skeletal Dysplasias: Ellis van Creveld syndrome, diastrophic dysplasia, chondrodysplasia punctata, camptomelic dysplasia, atelosteogenesis, and mesomelic dysplasia. Neuromuscular and Neurologic abnormalities: arthrogryposis multiplex congenita, myotonic dystrophy, spinal muscular atrophy,  neural tube defects, holoprosencephaly, and hydranencephaly. Genetics
Clubfoot can be diagnosed prenatally as early as 13 weeks of gestation via ultrasound. According to the Society of Maternal-Fetal Medicine, a diagnostic testing for genetic causes is recommended when clubfoot is diagnoses prenatally. If prenatal screening is suspicious for aneuploidy, karyotype analysis or chromosomal microarray (CMA) may be performed. However, if patients decline diagnostic testing, Cell-Free DNA is another screening option to identify high-risk pregnancies for aneuploidy and it is not diagnostic.