Abnormal urethra formation in mouse models of split-hand/split-foot malformation type 1 and type 4

Urogenital birth defects are one of the common phenotypes observed in hereditary human disorders. In particular, limb malformations are often associated with urogenital developmental abnormalities, as the case for Hand-foot-genital syndrome displaying similar hypoplasia/agenesis of limbs and external genitalia. Split-hand/split-foot malformation (SHFM) is a syndromic limb disorder affecting the central rays of the autopod with median clefts of the hands and feet, missing central fingers and often fusion of the remaining ones. SHFM type 1 (SHFM1) is linked to genomic deletions or rearrangements, which includes the distal-less-related homeogenes DLX5 and DLX6 as well as DSS1. SHFM type 4 (SHFM4) is associated with mutations in p63, which encodes a p53-related transcription factor. To understand that SHFM is associated with urogenital birth defects, we performed gene expression analysis and gene knockout mouse model analyses. We show here that Dlx5, Dlx6, p63 and Bmp7, one of the p63 downstream candidate genes, are all expressed in the developing urethral plate (UP) and that targeted inactivation of these genes in the mouse results in UP defects leading to abnormal urethra formation. These results suggested that different set of transcription factors and growth factor genes play similar developmental functions during embryonic urethra formation. Human SHFM syndromes display multiple phenotypes with variations in addition to split hand foot limb phenotype. These results suggest that different genes associated with human SHFM could also be involved in the aetiogenesis of hypospadias pointing toward a common molecular origin of these congenital malformations.

Treatment of congenital upper extremity problems

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Describe the terminology and classification of congenital hand anomalies. 2. Describe the incidence and embryogenesis of some common congenital hand anomalies. 3. Discuss the general principles and goals for treatment of congenital hand anomalies. 4. Describe the management of five of the more common congenital hand anomalies (syndactyly, short digits, thumb duplication, hypoplastic thumb, and radial dysplasia).

SUMMARY

Congenital hand anomalies can cause substantial emotional and functional problems. This article reviews the etiology, classification, and management of some of the more common hand anomalies. A general approach to the patient and the goals of treatment are reviewed, as is the approach to five specific congenital hand anomalies: syndactyly, short digits, thumb duplication, hypoplastic thumb, and radial dysplasia.

The hypoplastic thumb

Thumb hypoplasia is part of a spectrum of radial longitudinal deficiencies involving the upper limb. Systemic involvement of other organ systems is not uncommon, thus requiring a team approach to management. Because of the variety of anatomic abnormalities associated with thumb hypoplasia, clinical and intraoperative evaluation of the thumb must be precise. Effective management of thumb hypoplasia requires an understanding of the embryology, epidemiology, classification, presentation, and management options. Management, which is primarily determined by the grade of thumb hypoplasia, may include nonsurgical techniques, reconstruction, pollicization, and, recently, microsurgical procedures.

Genetics of congenital hand anomalies

Congenital limb malformations exhibit a wide spectrum of phenotypic manifestations and may occur as an isolated malformation and as part of a syndrome. They are individually rare, but due to their overall frequency and severity they are of clinical relevance. In recent years, increasing knowledge of the molecular basis of embryonic development has significantly enhanced our understanding of congenital limb malformations. In addition, genetic studies have revealed the molecular basis of an increasing number of conditions with primary or secondary limb involvement. The molecular findings have led to a regrouping of malformations in genetic terms. However, the establishment of precise genotype-phenotype correlations for limb malformations is difficult due to the high degree of phenotypic variability. We present an overview of congenital limb malformations based on an anatomic and genetic concept reflecting recent molecular and developmental insights.

Embryology of the upper limb: the molecular orchestration of morphogenesis

Accumulating data on the molecular interactions that occur during limb development have greatly enhanced our understanding of the process of limb morphogenesis. In this chapter, the key morphologic events are described, the broad categories of molecules involved are defined, the known molecular cascades and specific pathways that orchestrate limb development are reviewed. In addition, cascades disrupted by known genetic mutations associated with limb malformations are identified.

An introduction to congenital hand anomalies

The intention of this introduction is to provide a platform from which ensuing articles may deal with the details of management of specific entities. A basic knowledge of the process of limb development and an appreciation of our current knowledge of the causations of abnormal limb development are necessary to assist the surgeon in explanation as to how and why the child has the limb anomaly. Undoubtedly it is from this knowledge that prevention and improved management will evolve in the future. Some words about classification are appropriate. This is always a contentious issue, as classification cannot currently be precisely related to causation but is necessary such that those working in the field can speak in one language and understand each other. Finally, I will outline a philosophy on which to base both indications for, and timing of surgical intervention.

The Windblown Hand - Diagnosis, Clinical Picture and Pathogenesis

The syndrome of the windblown hand deformity is a complex constellation of malformations affecting not only the head and the feet but also the hands in a quite distinct manner. In the hand, it involves congenital bilateral flexion contracture with ulnar deviation of the metacarpophalangeal joints. The thumb is characteristically adducted (reaching the palm; "thumb-in-palm deformity") with flexion of the MP joint and hyperextension of the IP joint. The etiology is basically unknown. We present two theories based on knowledge derived from the disciplines of evolution biology and embryology. We believe that the atavistic appearance of phylogenetically primitive muscle groups in conjunction with an impaired rotation of the extremities during embryological development account for this malformation syndrome.

Teratogenic Mechanisms of Longitudinal Deficiency and Cleft Hand

In order to better understand the teratogenic mechanisms of congenital defects of the digits, we analyzed clinical cases and induced similar types of congenital hand anomalies in rat fetuses by oral administration of busulfan. In clinical cases, radial and ulnar deficiencies had common characteristic features. We induced radial and ulnar deficiencies in rat fetuses with the same drug. Radial and ulnar deficiencies induced in rats have similar clinical manifestations and these anomalies might be caused by the same teratogenic mechanism. Then, the formation of the digital rays was examined histologically. The results of histological examination suggested that these deficiencies were not caused by localized damage of the limb bud. They also suggested that the cause of missing digits in longitudinal deficiency is closely related to a deficit of mesenchymal cells in the limb bud. Cleft hand is considered to be one of the types of longitudinal deficiency. However, several investigators have suggested that the abnormal induction of finger rays in the process of formation of fingers induced central polydactyly, osseous syndactyly and also cleft hand. X-rays of the clinical cases and skeletal changes of the anomalies induced in rats appear to demonstrate that cleft hand formation proceeds from osseous syndactyly and central polydactyly. The results of our experimental study show that the critical periods of central polydactyly, osseous syndactyly and cleft hand are the same. They also suggest that central polydactyly, syndactyly and cleft hand might be induced when the same teratogenic factor acts on embryos at the same developmental stage in the human being. Because they have a similar causation, cleft hand, syndactyly and central polydactyly should be classified into the same entity, that is, abnormal induction of digital rays. Based on these clinical and experimental studies, we modified the Swanson classification. In our modified classification, typical cleft hand, syndactyly and polydactyly are included in the same category of abnormal induction of digital rays as the fourth new category.

Prenatal diagnosis and confirmation of the acrofacial dysostosis syndrome type Rodriguez

The group of acrofacial dysostosis (AFD) syndromes is very heterogeneous and contains many different entities. In 1990, Rodriguez et al. [1990: Am J Med Genet 35:484-489] described a new type of AFD characterized by severe mandibular hypoplasia, phocomelia and oligodactyly of the upper limbs, absence of fibulae, microtia, cleft palate, internal organ anomalies including arrhinencephaly and abnormal lung lobulation, and early lethality. We describe another case of AFD type Rodriguez, identified by prenatal ultrasonography at 25 weeks of gestation.

[Central agenesis of the hand]

Central aplasia represent under 10% of congenital malformations of the hand. It is characterised by the partial or complete absence of the median ray. We adopted the classification of Swanson and considered this anomaly a stop of median longitudinal development. We separate 2 groups: Hand in folk: the aplasia interested only the median digits, all metacarpal are present. Hand in lobster's pincer: all median rays are absent including the metacarpal. We report a set of 16 children carriers of 23 central aplasia of the hand, it was about 14 hands in lobster'pincer and 9 hands in folk. In any case, the gene was merely aesthetic, the hand's function was complete. A child has been operated, and benefitted a closing of the median crack defect, he had a free thumb. For the other cases, abstention has been decided, indeed to close this cracks deprive these hands of a first corner the alone present.

Congenital aplasia or hypoplasia of extensor tendons of the hand--a case report and review of the literature

An 8-year-old boy presented with inability to extend his fingers. Examination revealed congenital hypoplasia of the extensor tendons. He was treated with tendon transfers. We present a review of the literature and management of such cases.

The molecular control of upper extremity development: implications for congenital hand anomalies

As the molecular aspects of limb development are being unraveled, more of the congenital anomalies seen by hand surgeons in the clinical setting will have an identifiable molecular basis. The majority of the data available regarding the molecular development of the upper extremity have come from experimental animal studies, specifically the mouse and chicken. These findings are being discovered by either direct surgical and molecular manipulation of the developing limb or by production of mice deficient in specific genes. Relatively few specific human mutations that cause limb abnormalities have been identified. Hand surgeons should be aware of the basic molecular pathways controlling limb development because they are in a unique position to be able to identify patients with such deformities. In turn, detailed clinical descriptions of congenital anomalies affecting the upper extremity will advance the understanding of the cellular events controlled by the molecular pathways of limb development. This review describes the general molecular basis of limb development and correlates it with disease processes affecting the upper extremity.

An autopsy case of Adams-Oliver syndrome

We report an autopsy case of a male fetus with Adams-Oliver syndrome. His mother was a healthy, 31-year-old woman and her family and past histories were unremarkable. Therapeutic termination was done at 28(+6) weeks gestational age due to oligohydramnios detected by antenatal ultrasonography. Chromosomal study revealed normal karyotype. On autopsy, characteristic transverse terminal defect of four extremities was found. Both feet were short and broad. All toes were rudimentary with no nails and fingers were irregularly short. On infantogram, all toe-bones were stubby and rudimentary. The middle and terminal phalanges of 2nd, 3rd & 5th fingers and the terminal phalange of 4th finger on the right hand were absent. The middle and terminal phalanges of 2nd & 5th fingers and terminal phalange of 3rd finger were defected on the left hand. His abnormalities were consistent with features of Adams-Oliver syndrome, which has not been reported in Korea.

Prenatal sonographic diagnosis of Holt-Oram syndrome

Holt-Oram syndrome is an autosomal dominant disorder characterized by heart defects in combination with characteristic upper-limb abnormalities. A woman with no family history of genetic diseases underwent prenatal sonography at 25 weeks' menstrual age to screen for fetal anomalies. Sonography revealed abnormalities in the upper limbs and heart. The limb abnormalities included bilateral absence of radii and thumbs: the left hand had no carpal or metacarpal bones, and each of the 4 fingers on that hand had only 1 phalangeal bone. Cardiac malformations included an atrial septal defect and Ebstein's anomaly. Other structures were normal. Prenatal cytogenetic analysis by cordocentesis revealed a normal 46,XY karyotype. Spontaneous labor and delivery at 34 weeks' menstrual age produced a 1,960-g male infant who died of cardiac insufficiency shortly after birth. The postnatal appearance and autopsy findings confirmed the prenatal findings. In this case, Holt-Oram syndrome was readily diagnosed by prenatal sonography.

Genetics of limb development and congenital hand malformations

The vertebrate limb bud develops along three different axes: proximodistal, anteroposterior, and dorsoventral. Several genetic factors responsible for control of each of the three limb axes have been identified. The genes involved interact in complex feedback loops to achieve proper arrangement and differentiation of tissues. Most of the available information on limb development and patterning has come from studies carried out in the lower vertebrates. In recent years, an increasing number of studies have been unraveling the genetic basis of human hand malformation phenotypes. At present, genes responsible for preaxial polydactyly, split hand/split foot malformation, and brachydactyly type C have been localized, and the gene responsible for synpolydactyly has been identified. In this paper, we present an overview of the genetic factors involved in limb development, followed by summarized discoveries in the genetics of human congenital hand malformations.

Cystic hygroma as an early first-trimester ultrasound marker for recurrent Fryns' syndrome

We present a case of a fetus who at a 12-week ultrasound examination was shown to have a large cystic hygroma. Fryns' syndrome was suspected because the mother's previous pregnancy had been affected by the condition. Pathological examination confirmed the diagnosis at this early stage of gestation. In families with increased risk for Fryns' syndrome, first-trimester ultrasound screening should be offered to exclude cystic hygroma as an ultrasound marker for this most often lethal malformation.

Hirschsprung's disease, colonic atresia, and absent hand: a new triad

Colonic atresia (CA) has been reported in association with Hirschsprung's Disease (HSCR) on 11 previous occasions. In most reported cases the atresia has involved the right side of the colon; but in this, the twelfth case report, the atresia involved the left side of the colon, with aganglionosis of the entire distal gut. In addition, the child had an absent hand. The authors believe that this triad has not been reported previously. The literature is reviewed, and possible mechanisms are discussed.

Congenital scalp defect, distal limb reduction anomalies, right spastic hemiplegia and hypoplasia of the left arteria cerebri media. Further evidence that interruption of early embryonic blood supply may result in Adams-Oliver (plus) syndrome

In this report we describe a male patient with the interesting combination of a large congenital scalp defect, distal limb reduction anomalies, right spastic hemiplegia and hypoplasia of the left arteria cerebri media. Follow-up data from birth up to the age of 18 years revealed positive evolution with low to normal intelligence. The findings in the present patient, i.e. an Adams-Oliver syndrome associated with a severe neurological deficit, are best explained as resulting from interruption of the early embryonic blood supply.

[Treatment of a radial club hand]

The present study includes a total of 12 patients who had a longitudinal radial deficiency which produced a club hand. 17 hands were affected. Complete radius aplasia (type C) was most frequent, followed by partial radius aplasia (type D) and radius hypoplasia (type E). 7 patients (8 hands) were treated surgically by centralisation of the ulna. Average age at surgery was 46 months. Indications for surgery were followed according to Blauth. The results were evaluated using the criteria of Hippe and Blauth. All patients were pleased with the results, and in each case there was no doubt that function and appearance could be improved. The results of this study demonstrate that correction of radial clubhand by centralisation of the ulna produces a good functional result if the criteria of Blauth are followed: functional mobility of the elbow joint of more then 90 degrees, and the possibility of passive correction of the deformity preoperatively.

Mirror image duplication of the hands and feet: report of a sporadic case with multiple congenital anomalies

Mirror image duplication of the hands and feet is a rare entity. Based on 3 previous reports, findings include nasal abnormalities, dimelia of ulna and fibula, tibial hypoplasia and mirror image duplication of hands and feet. We report on a sporadic case in which mirror image duplication was associated with multiple congenital anomalies. Although these cases may represent variable expression of the same dominantly transmitted complex polysyndactyly syndrome, it is possible that mirror image duplication of the hands and feet is a manifestation common to a number of distinct clinical entities. During limb bud development, duplication and aberrant positioning of the zone of polarizing activity in relation to the apical ectodermal ridge may account for the anatomic abnormalities of the hands and feet in these patients.

Geleophysic dysplasia: a report of three affected boys--prenatal ultrasound does not detect recurrence

Geleophysic dysplasia is characterized by short stature with short limbs and brachydactyly, a "happy" facial appearance, and joint contractures. Infiltration of heart valves and liver with a mucopolysaccharide-like substance has been demonstrated in some patients. A metabolic pathogenesis is suspected, but has not yet been identified. We report on 3 boys with the condition, 2 of whom are brothers. Serial ultrasound scans were performed on 2 of the cases during pregnancy, but short limbs did not become obvious until after 28 weeks of gestation, making it an uninformative procedure for prenatal diagnosis.

Symmetrical terminal transverse limb defects: report of a twenty-week fetus

A 20-week gestation hydropic Thai fetus is reported who had symmetrical absence of each hand and forefoot with persistence of digit-like nubbins on each limb. The histologic studies showed there was calcified acellular material in the digit-like nubbins, consistent with infarcted blood vessels, and cartilaginous structures that represented possibly the distal metacarpal articulating surface. The red blood cell indices of both parents were consistent with their being heterozygous for a hemoglobinopathy, such as alpha-thalassemia, which is common in Thais. The infarcted blood vessels could be the result of thrombosis of the digital arteries in the fetus due to a hemoglobinopathy such as hemoglobin Bart's, just as rabbit fetuses homozygous for brachydactyly have transverse terminal digit amputations following digital vessel occlusions due to macrocytic anemia. This was the only child with symmetrical absence of the hands and feet identified among 123,489 liveborn and stillborn infants surveyed for major malformations.

Anencephaly with spinal dysraphism, cleft lip and palate and limb reduction defects

We report three unrelated fetuses presenting with anencephaly, spinal dysraphism, cleft lip and palate and limb reduction defects. Review of the literature suggests that this association may be more commonly found than previously recognized and may indicate severe disturbance in early embryogenesis.

[Congenital hand malformation--local disturbance in the limb bud and longitudinal deficiency: an experimental study on the pathogenesis]

Experimental congenital malformation produced in fetal chickens to investigate any correlation between a local disturbance in the limb buds and longitudinal deficiency, and to elucidate the pathogenesis of radial and ulnar ray deficiencies. Fertilized White Leghorn eggs were incubated at 38.0 degrees C and windowed. The right wing bud of the embryos was locally cauterized using a bipolar microcoagulator under a microscope. Cauterization was carried out from 2.5 days to 5.5 days of development, at 12-hour intervals. Each wing bud was divided into 6 areas: axial (distal and proximal), preaxial (distal and proximal) and postaxial (distal and proximal). After cauterization the eggs were sealed with micropore tape and further incubated until the 21st-23rd day. The chick wings were then removed and investigated macroscopically and roentgenographically. The wing buds had been examined microscopically after cauterization on the 3rd day until ray deficiencies were produced on the 5th day. Radial ray deficiencies were produced by cauterization in the distal preaxial area, and ulnar ray deficiencies by cauterization in the distal postaxial area. These results indicated a peculiarity of the longitudinal axis. However, the critical periods of the radial and the ulnar ray deficiencies were the same; from immediately after the formation of the wing bud to before the formation of the digital plate. The patterns of the combined defects in the digits and of other associated deformities were quite similar to those found in human malformations. Microscopically necrosis in the mesoderm and in the overlying ectoderm of the pre and postaxial areas of the tip of a wing bud caused defects in the cartilaginous primordium in the same ray.

Sandrow syndrome of mirror hands and feet and facial abnormalities

In 1970, Sandrow et al. (J Bone Joint Surg 52-A:363-370) described a syndrome of ulnar and fibular dimelia with facial abnormalities present in 2 generations in a family. We describe a new patient with similar manifestations, establishing this constellation of anomalies as a distinct syndrome.

Congenital constriction band syndrome. Pathophysiology and treatment

The clinical manifestations of 88 children with congenital constriction band syndrome involvement of the hand were reviewed. Seventy-five of these children had evidence of digital or limb amputations, with 235 upper limb amputations and 138 lower limb amputations. In the hand, digital amputations were most common in the index, middle, and ring fingers, whereas in the foot, amputations of the hallux were most often noted. Band indentation was often present at multiple levels. Proximal bands may be associated with neural compression. Syndactyly was invariably associated with a proximal interdigital sinus or cleft and was frequently associated with distal amputation. Examination of a 27-week gestation stillborn specimen having manifestations of congenital constriction band syndrome demonstrated the intrauterine biologic response to band constriction. The variable clinical manifestations of congenital constriction band syndrome can best be explained as the response of the growing, embryologically defined limb to intrauterine deformation or band-induced compression and ischemia.

Treatment of preaxial polydactyly

Preaxial polydactyly is the result of aberrant bifurcation of the embryonic preaxial anlage. Effective reconstruction of thumb duplication requires careful evaluation of all components. Skin, nail, bone, ligament, and musculoskeletal elements must be combined to reconstruct an optimal digit.

Ultrasonography of the normal and abnormal antenatal development of the upper limb

The degree of severity of congenital deformities of the hand, as well as any coexisting congenital anomaly should be evaluated especially if there is a possibility of therapeutic termination of pregnancy. This may be relatively easy in the case of some major malformations which affect the neurological or intellectual capacity of the child. It is however more difficult in the presence of predominantly motor anomalies, and with distally based anomalies of the upper limb which may be amenable to later reconstructive surgery.

[Gibbous hand deformity--carpe bossu]

Fiolle (10) was the first to describe a bony protuberance of a carpometacarpal joint and named it carpe bossu. This anomalous anatomical condition occasionally becomes a--widely unknown--common clinical entity. The reasons are discussed. The clinical diagnosis can be confirmed by a lateral tangential radiograph. Discomfort and pain are rare and can be treated usually by conservative means, surgery is seldom indicated.

Teratogenic relationship between polydactyly, syndactyly and cleft hand

Several investigators have suggested that polydactyly, syndactyly and cleft hand might have arisen from a common teratogenic mechanism. To confirm this hypothesis, 75 hands with these anomalies were analysed. Advanced cases with central polydactyly or osseous syndactyly in which the fusion area extends as far as the proximal phalanx and metacarpus are identical to typical cleft hand. The author has induced the same deformities using myleran in rat foetuses. The clinical features of these anomalies in rats were the same as those in clinical cases and the critical periods of these anomalies were also the same. The findings suggest that these hand anomalies may appear in human beings when the same teratogenic factor acts on the embryo at the same developmental period and that they should belong to the same teratogenic entity.

[An experimental study on the pathogenesis of congenital hand malformation--with reference to local disturbance in the limb bud and congenital constriction band syndrome]

In order to study congenital constriction band syndrome, we performed local cauterization of the lower limb buds of embryos in fertilized white leghorn eggs between hour 0 on day 4 (day 4-0) and day 7-0 of incubation. Constriction bands, acrosyndactyly, and amputation of digits, malformations characteristic of this syndrome, were all induced by intervention after day 5-0, when digital ray formation was first observed, indicating that they all develop after ray formation. Histological examination showed that encapsulation and shedding of the lesion containing hematoma and necrotic tissue at the distal end of a digital ray led to digit amputation. When the cells encapsulating this lesion extend over another digital ray, moreover, the ray tips fuse, while the rest of the two digits involved remain discrete-resulting in acrosyndactyly.