Esophoria is an eye condition involving inward deviation of the eye, usually due to extra-ocular muscle imbalance. It is a type of heterophoria. Cause
Causes include:

Refractive errors
Divergence insufficiency
Convergence excess; this can be due to nerve, muscle, congenital or mechanical anomalies.Unlike esotropia, fusion is possible and therefore diplopia is uncommon. References


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Osteoblasts deficient in FKBP65 have a buildup of procollagen aggregates in the endoplasmic reticulum which reduces their ability to form bone. Furthermore, Bruck syndrome type 1 patients have under-hydroxylated  lysine residues in the collagen telopeptide and as a result show diminished hydroxylysylpyridinoline cross-links.Type 2  encodes the enzyme, lysyl hydroxylase 2, which catalyzes hydroxylation of lysine residues in collagen cross-links. PLOD2 is most expressed in active osteoblasts since collagen cross-linking is tissue-specific. Mutation in PLOD2 alters the structure of telopeptide lysyl hydroxylase and prevents fibril formation of collagen type 1. Bone analysis shows the lysine residues of telopeptides in collagen type 1 are under-hydroxylated. Diagnosis
Diagnosis of Bruck syndrome must distinguish the association of contractures and skeletal fragility. Ultrasound is used for prenatal diagnosis. The diagnosis of a neonate bears resemblance to arthrogryposis multiplex congenital, and later in childhood to osteogenesis imperfecta. Management
Until more molecular and clinical studies are performed there will be no way to prevent the disease. Treatments are directed towards alleviating the symptoms. To treat the disease it is crucial to diagnose it properly. Orthopedic therapy and fracture management are necessary to reduce the severity of symptoms. Bisphosphonate drugs are also an effective treatment. History
The first case was in 1897 of a male who was described by Bruck as having bone fragility and bone contractures. Bruck was credited with the first description and the diseases eponym. References
Further reading
Breslau-Siderius, E. J.;  et al. (1998). "Brack syndrome: a rare combination of bone fragility and multiple congenital joint contractures". Journal of Pediatric Orthopaedics B.