Tibial Hemimelia in One of the Identical Twins

Abstract

Tibial hemimelia, a rare congenital anomaly, is characterized by deficiency of the tibia with relatively intact fibula. The incidence of congenital deficiency of the tibia is approximately 1 per 1 million live births. The percentage of monozygotic twins is 0.8% of all newborns. Therefore, the occurrence of tibial hemimelia in monozygotic twins is 1 case per 125 million. The purpose of this article is to present a case of identical twins, in which 1 had tibial hemimelia, a double metatarsal bone and preaxial polydactyly and the other had no alterations. The patient that was affected had an anomaly in the left leg and foot. She had 7 fingers in her left foot and a left duplicated great toe. Her legs had a 3-cm difference in length, rigid inversion, adduction of feet, and severe bowing. A roentgenogram showed right tibial hemimelia with intact fibula corresponding to Jones type 3 and the first metacarpo was duplicated with a proximal osseus synostosis. Karyotyping confirmed that the twins were monozygotic. Only 1 of the identical twins had tibial hemimelia, a double metatarsal bone, and preaxial polydactyly. Congenital defects may result from aberrations in the developmental stage, the growth stage, or both. Hemimelia may result from a primary failure to form an anlage, or a primary failure to chronologically synthesize collagen. This case shows that tibial hemimelia can have variable phenotypic manifestations.

Tibial hemimelia: New classification and reconstructive options

“…Werner’s syndrome [25] is an autosomal dominant disorder that is currently thought to be a variant of triphalangeal thumb-polysyndactyly syndrome (TPTPS). Both diseases have been mapped to chromosome 7q [26]. A deletion on chromosome 8q, contiguous with Langer–Giedion syndrome, or type II tricho–rhino–phalangeal syndrome (TRPS II) may also be responsible for tibial hemimelia [27].…”

Tibial hemimelia–polydactyly–five-fingered hand syndrome associated with a 404 G>A mutation in a distant sonic hedgehog cis-regulator (ZRS)

“…Werner first described a case of polydactyly of the hands, digitalization of the thumb, short lower limbs with aplasia of the tibias, and polydactyly of the toes in 1915 [1]. Reber [4] reported on a boy with a full manifestation of this complex anomaly whose father had triphalangeal thumbs only, and Leite et al [5] reported on a case of identical twins, one of whom had complete tibial hemimelia and preaxial polydactyly on the left side, whereas the other had no alterations at all. Vargas et al [2] reported on a family with 10 affected members spanning three generations, and Agarwal et al [3] reported on a family with seven affected members, also over three generations, who showed bilateral agenesis of the whole tibia and distal radius, five-fingered hands, and pedal polysyndactyly.…”

A case of bilateral tibial hemimelia type VIIa

“…[6] Family history of congenital anomaly of tibia, as well as intra-familial phenotypic variations of the defect in twin pregnancy has been reported. [789] The anomalies in which the number of skeletal elements increased arise during the first 7 weeks of intrauterine life. A decrease in the number of skeletal parts may arise after, as well as during, this 7-week period.…”