Brachydactyly Tibial Hypoplasia - An Overview

Introduction

Brachydactyly is a medical word that means "short finger." Compared to other long bones and other body components, the shortness is considered relative. Brachydactyly is a dominant, hereditary characteristic. Although it most frequently manifests as several congenital syndromes can also include it along with other defects. Other hand deformities like syndactyly, polydactyly, and reduction abnormalities may coexist with brachydactyly. The responsible gene deficiency has been found in most solitary brachydactyly and certain syndromic types of brachydactyly.

What Is Tibial Hypoplasia?

A tibial hypoplasia syndrome is an uncommon form of hereditary dysostosis characterized by bilateral tibial hypo/aplasia, missing thumbs, and concomitant reduction abnormalities of the upper and lower limbs. A hypoplastic or aplastic tibia is a defining feature of the uncommon congenital limb deficit known as tibial hemimelia. It reflects a spectrum of malformations, from moderate tibial hypoplasia to complete tibia absence. The literature has several categories based on the radiological description.

• Preaxial mirror polydactyly.

• Split hand/foot syndrome—ectrodactyly.

• Polydactyly—triphalangeal thumb syndrome (Werner syndrome).

• Micromelia-trigonal brachycephaly syndrome.

What Is the Cause of Brachydactyly Tibial Hypoplasia?

• Broadly speaking, brachydactyly is an autosomal dominant characteristic that is inherited and is a congenital (existing at birth) disorder in which the fingers on one hand do not develop correctly when the infant is growing in their mother's womb.

• Nonetheless, there can be exceptions if antiepileptic medications were administered during pregnancy or if there was inadequate blood supply to the extremities during infancy.

• Mutations in the Indian hedgehog gene (IHH), found on chromosome 2q35-36, can result in type A1 brachydactyly.

• With isolated brachydactyly, the hands and feet have shorter bones. Phalanges, metacarpals, metatarsals, carpals, and tarsals are possible examples of this.

• Isolated brachydactyly is categorized based on the locations they impact, and each variety has a unique set of symptoms.

What Are the Clinical Components of Brachydactyly Tibial Hypoplasia?

• Mentally, these patients are healthy. Patients often have two limbs afflicted. However, all four extremities might be affected.

• Fibular and/or ulnar aplasia/hypoplasia, severe metacarpal and phalangeal hypoplasia of the hands and/or feet (fused tarsal and metatarsal bones and highly malformed proximal phalanges), and/or ectrodactyly of the hands and/or feet are also possible defects.

• The term "ectrodactyly" (derived from the Greek words "ektroma" for "abortion" and "daktylos" for "finger") refers to the lack of at least one whole digit (both metacarpal/metatarsal and phalanges).

• Usually, the damaged limb(s) is shortened. It is possible to have syndactyly or monodactyly of the hands and feet.

• There are no apparent differences between men and females, familial and sporadic instances. However, the upper limb seems to be more frequently afflicted in family cases (especially if they are female).

• It is possible to have tibial and radial defects (hypoplasia, extreme angulation, frequently with dimpling of the overlying skin).

• Femoral involvement, which can affect the proximal femur and/or the acetabulum, is uncommon and refers to bilateral hypoplastic femurs.

• On occasion, the knee or hip may also be affected. Apart from two incidences of umbilical hernia, no other issues have been recorded.

What Is the Diagnosis of Brachydactyly Tibial Hypoplasia?

• Usually, anthropometric, clinical, or radiological approaches are used to identify brachydactyly.

• When the size disparity becomes apparent during infancy or youth, it is often discovered early. When the discrepancy in phalange size becomes more obvious, it is often diagnosed.

• The symptoms are physically examined, and medical professionals take radiographs as part of their examination (X-rays). The X-rays demonstrate which bones are shorter.

• The X-rays reveal if some bones are shorter than expected or are shorter than average. In addition to these actions, the medical professional could do a genetic test.

• Testing may be done to determine the malfunctioning gene or if the condition has been handed down through the family.

• If the family's underlying mutation is known, amniocentesis is performed after the 14th week of gestation, and chorionic villus samples studied at 11 weeks can be used for molecular analyses to provide a prenatal diagnosis.

• The kind of genetic counseling provided relies on the inheritance pattern of the particular kind of brachydactyly present in the family as well as the presence or absence of comorbid symptoms.

What Is the Treatment of Brachydactyly Tibial Hypoplasia?

• Treatment is only required if brachydactyly impairs phalangeal function.

• Reconstructive surgery enhances function and the patient's ability to use their phalanges in the few instances where the function is compromised.

• Cosmetic surgery is sometimes mistaken for reconstructive surgery but varies in that it may not be deemed medically required. In contrast, reconstructive is done to enhance the appearance of the damaged regions, another form of therapy.

• Cosmetic surgery is only necessary if the brachydactyly interferes with hand function or is desired for cosmetic reasons.

• Ergotherapy and physical therapy improve hand function.

• The kind of genetic counseling provided relies on the genetic basis of the particular kind of brachydactyly present in the family and the presence or absence of associated symptoms.

• The likelihood of brachydactyly recurrence in affected individuals' kids is 50 % regardless of sex if the condition is inherited in a genetically dominant pattern. Many kinds of brachydactyly frequently have varying degrees of severity and partial penetrance.

• If brachydactyly has a rare genetic inheritance pattern, there is a 25 % chance that it may reoccur in a sibling of an afflicted patient. However, though afflicted siblings may still have varying symptoms, variability is typically reduced in autosomal recessive variants.

• Rarely, untreated isolated brachydactyly can make it difficult to perform everyday tasks like walking or grasping objects, which lowers the quality of life overall.

Conclusion

An uncommon disorder called brachydactyly tibial hypoplasia causes short fingers and an underdeveloped or absent shin bone. As well as being recognized as brachyphalangy, polydactyly, and absent tibiae, this condition is connected to polydactyly, preaxial I, and polydactyly. HMGB1 is a significant gene linked to brachyphalangy, polydactyly, and tibial aplasia or hypoplasia (High Mobility Group Box 1). Skin and kidney are associated tissues, and ptosis and high palate are linked traits. There is no single, universal management or course of action for all brachydactyly types.