Oculodentodigital dysplasia is a rare genetic disorder characterized by microphthalmia, tooth abnormalities and syndactyly between the fourth and fifth fingers.
Oculodentodigital dysplasia (ODD dysplasia) syndrome may be inherited in an autosomal dominant or autosomal recessive manner. The typical clinical findings in this syndrome depend on the type of inheritance, with multiple organ systems being afflicted, namely the head, eyes, mouth cavity, skin, skeletal, and nervous system [1].
Patients with the autosomal dominant form of ODD dysplasia are usually born with microphthalmia with or without microcephaly. The other common ocular findings include glaucoma, strabismus, iris atrophy, micro cornea, epicanthic folds, a narrow palpebral fissure and atrophy of the eye [2] [3].
The dental problems occurring in patients with ODD dysplasia include small teeth predisposed to caries due to insufficient enamel. Irregular teeth, missing teeth, and early tooth loss are the other findings.
A slender nose with narrow and/or underdeveloped nostrils is another typical finding. Cleft lip or palate may also be observed.
A major sign of ODD dysplasia syndrome is the syndactyly between the fourth and the fifth fingers and/or the fourth and the fifth toes. Apart from being pathologically connected, the fingers and toes may also be unusually bent (camptodactyly).
In some cases, neurologic deficits may be present. Patients may suffer from ataxia, dysarthria, spastic paraplegia, deafness and problems with urination and defecation [4] [5] [6].
Palmoplantar keratoderma has also been reported in some patients. The hair may be fragile, dry, thin and shows extremely slow growth [7].
Signs and symptoms in the autosomal recessive form of ODD dysplasia are typically more severe. The eyes are extremely small and slender, with the interpupillary distance wider than normal. Some patients may even go completely blind. The skeletal changes are more pronounced and the bones of the skull, lower jaw, and the collar bone show an abnormal thickening.
ODD dysplasia must be distinguished from several other conditions presenting with similar symptoms. Foremost among these is the oro-cranio-digital syndrome, an autosomal recessive condition characterized by numerous abnormalities such as microcephaly, cleft lip and/or palate and growth retardation. This disorder is extremely rare and shows a slight female preponderance.
Amelogenesis imperfecta is another rare congenital condition in which defective formation of the tooth enamel results in the teeth being more sensitive to extremes of temperature. Early tooth loss with frequent dental infections are the other common clinical features.
A group of hereditary conditions, termed the ectodermal dysplasias, may also be a cause for defective enamel formation, with missing teeth and hair problems being the usual presenting features. Other organs derived from the ectodermal germ layer, most notably the skin, are also routinely affected.
Saethre-Chotzen syndrome is an autosomal dominant disorder, characterized by various malformations of the head, skeleton, and skin of the fingers and toes that may present with mental retardation.
A proper diagnosis rests on the identification of the typical clinical features of ODD dysplasia. However, the symptoms and their severity vary from case to case and hence, the recognition of this disorder based primarily on its clinical manifestations is not always apparent. When ODD dysplasia is suspected, the diagnosis can be confirmed by certain molecular tests. The defective gene is situated on 6q chromosome and genetic mapping studies may help to further elucidate the precise location of the mutation [8] [9] [10].