Short phalanges may not be clearly evident by fetal ultrasonography early in development, and will only be visible later on, if expressed. Prenatal diagnosis is usually not indicated for isolated forms of brachydactyly, but may be appropriate in syndromic forms. Antenatal diagnosis and genetic counseling.General considerations of brachydactylies We will focus on isolated brachydactyly, although selected syndromic forms will also be discussed. Therefore, we follow here the definitions of the various types of brachydactyly as described by Temtamy and McKusick. No other classifications of brachydactyly, apart from a few appearing in the Russian and Romanian literature, are known to us. This system of classification has the advantage of being malleable to accommodate addition of any other recently discovered forms of brachydactyly mentioned in the literature. One of the most commonly used classifications of brachydactyly based on anatomic grounds was provided by Bell and further elaborated by Temtamy & McKusick. Brachydactyly may also go along with other hand malformations, such as syndactyly, polydactyly, reduction defects, or symphalangism. In isolated brachydactyly (Table 1), subtle changes elsewhere may still be present. ClassificationĪs in all congenital anomalies, brachydactyly can occur either as an isolated malformation or as a part of a complex malformation syndrome. The incidence and prevalence of these entries varied considerably. A similar search using brachydactyly as search term in the London Medical Databases (LMD) yielded 386 entities. Ī search of Online Mendelian Inheritance in Man using brachydactyly as key term provided 232 entries (isolated forms syndromes with brachydactyly skeletal dysplasias). The various types of isolated brachydactyly are rare, except for types A3 and D, which are common, prevalence being around 2%. They are usually static and arise during blastogenesis (1 st 8 weeks of embryonic life), thus they differ from osteochondrodysplasias that usually present at a later stage of development, typically affect the skeleton in general, and may continue to evolve as a result of continuous gene functioning throughout life. Dysostoses refer to abnormalities of individual bones, either in isolation or in combination with various abnormally formed bones. In the latest International nosology and classification of genetic skeletal dysplasias, brachydactyly was included as one of the dysostosis groups affecting the limbs. Brachydactyly is one of the ten categories of hand malformations classified by Temtamy & McKusick in their original work on the genetics of hand malformations. It indicates shortening of digits due to abnormal development of phalanges, metacarpals, or both. The term brachydactyly is derived from the ancient Greek (brachy-: short dactylos: digit). If brachydactyly forms part of a syndromic entity, prognosis often depends on the nature of the associated anomalies. Prognosis for the brachydactylies is strongly dependent on the nature of the brachydactyly, and may vary from excellent to severely influencing hand function. Physical therapy and ergotherapy may ameliorate hand function. Plastic surgery is only indicated if the brachydactyly affects hand function or for cosmetic reasons, but is typically not needed. There is no specific management or treatment that is applicable to all forms of brachydactyly.
The nature of genetic counseling depends both on the pattern of inheritance of the type of brachydactyly present in the family and on the presence or absence of accompanying symptoms. Molecular studies of chorionic villus samples at 11 weeks of gestation and by amniocentesis after the 14 th week of gestation can provide antenatal diagnosis if the causative mutation in the family is known.
In isolated brachydactyly, the inheritance is mostly autosomal dominant with variable expressivity and penetrtance.ĭiagnosis is clinical, anthropometric and radiological.
Brachydactyly may also be accompanied by other hand malformations, such as syndactyly, polydactyly, reduction defects, or symphalangism.įor the majority of isolated brachydactylies and some syndromic forms of brachydactyly, the causative gene defect has been identified. In isolated brachydactyly, subtle changes elsewhere may be present. To date, many different forms of brachydactyly have been identified. Brachydactyly can occur either as an isolated malformation or as a part of a complex malformation syndrome. The various types of isolated brachydactyly are rare, except for types A3 and D. Brachydactyly ("short digits") is a general term that refers to disproportionately short fingers and toes, and forms part of the group of limb malformations characterized by bone dysostosis.