ETIOLOGY OF CLUBFOOT

Etiologies of clubfoot

Idiopathic

Intrinsic

Chromosomal

Trisomy 18

Trisomy 9

Trisomy 13

Trisomy 21

Triploidy

          Deletions of chromosomes 18q, 4p, 7q, 9q, 13q

Connective tissue

Arthrogryposis

          Collagen defects

          Joint synostosis

Neurologic

          Anencephaly

          Anterior motor horn cell deficiency

Hydrancephaly

Holoprosencephaly

Meningomyelocele

Spina bifida

Muscular

Myopathy

Myotonic dystrophy

Skeletal dysplasia

Campomelic dysplasia

Chondrodysplasia punctata

          Diastrophic dysplasia

          Ellis-van Creveld syndrome

Syndromes

          Escobar syndrome

          Hecht syndrome

          Larsen's syndrome

Meckel- Gruber syndrome Gruber syndrome

          Multiple pterygium

          Pena Shokeir

          Smith-Lemli-Opitz

Zellweger's syndrome

Extrinsic

     Amniotic bands

Synechiae

     Early amniocentesis

     Intrauterine crowding

          Fibroids

          Multiple gestation

Oligohydramnios

                    Potter sequence

          Increased birthweight

     Breech

Nulliparity

     Seasonal variation

          Viral

Hyperthemia

     Substance use

          Maternal alcohol

          Maternal and paternal smoking

          Illicit drugs

The strongest evidence for an environmental cause of clubfoot comes from the Canadian Early and Mid-Trimester Amniocentesis Trial, a prospective randomized study that compared the safety and accuracy of early amniocentesis with midtrimester amniocentesis (3). In this trial, 29 (1.3%) of 2187 children of women in the early amniocentesis group compared with 2 (0.1%) of 2187 children of women in the mid-trimester amniocentesis group had talipes equinovarus; this was statistically significant (P = .0001). The occurrence of clubfoot increased to 15% in the setting of amniotic fluid leakage, although none of the cases with clubfoot had persistent oligohydramnios at the time of the detailed anatomic survey done at 18 to 20 weeks. This implies that it is not only the presence of oligohydramnios, but the timing of the oligohydramnios, that is important.

Evidence for intrinsic causes of clubfoot is illustrated in the observed recurrence risk.

· First-degree relatives of a person with idiopathic clubfoot are at a significantly increased risk of having clubfoot when compared with the general population.

· The recurrence risk for siblings with normal parents varies according to the gender of the affected sibling;

· the recurrence risk for a sibling of an affected male is 2%,

· the recurrence risk for a sibling of an affected female 5% .

· If a child and another family member have clubfoot, or both parents have clubfoot, the risk of having another affected child increases to 10% to 20% (4).

REFERENCES

1. Maffulli N. Opinion: Prenatal sonographic diagnosis of talipes equinovarus: does it give the full picture. Ultrasound Obstet Gynecol 2002;20:217-218.
2. Magriples U. Prenatal diagnosis of clubfoot. In: UpToDate, version 11.2. Wellesley, MA: 2003
3. Farrell SA, Summers AM, Dallaire L, Singer J, Johnson JM, Wilson RD, et al. Club foot, and adverse outcome of early amniocentesis: disruption or deformation? J Med Genet 1999;36:843-6.
4. Dietz F. The genetics of idiopathic clubfoot. Clin Orthop 2002;401:39-48.