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"Pacifier polydactyly" is defined in babies with a large edematous postaxial duplication attached by soft-tissue stalks that contain neurovascular elements. These serve in utero as pacifiers. Imminent ischemic necrosis was induced in all three by local trauma. Simple excision is the treatment of choice.
Male mice heterozygous for the dominant polydactyly gene Pdn (Polydactyly Nagoya) were crossed with normal or heterozygous females of the same strain. Pregnant females were treated with 5 mg/kg of cytosine arabinoside (Ara-C) on day 12 of gestation. The offspring were removed on day 18 of gestation and examined for external malformations, and the fore- and hindlimbs were examined by means of bone- and cartilage-stained cleared specimens. In +/+ x Pdn/+ matings, Pdn/+ fetuses, bearing preaxial polydactyly of the distal phalangeal type in the hindlimb and deformity of the 1st digit in the forelimb, were obtained in about 50% of the nontreated group. In treated fetuses, however, the incidence of polydactyly and deformity of the 1st digit decreased to 1.4 and 10.1%, respectively. Nontreated Pdn/Pdn fetuses exhibited preaxial polydactyly of the duplicated or triplicated metacarpal/metatarsal type both in the fore- and hindlimbs. In the treated Pdn/Pdn fetuses, the number of preaxial extra digits decreased in both limbs. Some hindlimbs of the treated Pdn/Pdn fetuses exhibited five metatarsals, normally. In the vitally stained specimens at 6 and 24 hours after injection of Ara-C, preaxial marginal necrotic zones (fMI) were observed in almost all of the treated embryos from +/+ x Pdn/+ matings. However, approximately half of the embryos did not exhibit fMI in the nontreated control group at the same stage. Those embryos deficient in fMI were regarded as Pdn/+. These findings indicated that a subteratogenic dose of Ara-C prevented the genetic expression of polydactyly in almost all Pdn/+ and some cases of Pdn/Pdn mice.(ABSTRACT TRUNCATED AT 250 WORDS)
Polydactyly of the hand, of the foot, and of the hand combined with the foot were studied. As noted in previous reports of polydactyly, inherited cases represent about 10% of polydactyly of the hand or foot, and unilateral involvement is more common than bilateral. In 495 cases of polydactyly 27 patients had polydactyly of the hands and feet. The extra digits in 21 of those 27 were in the same digital rays of the hand and foot. There were 14 inherited cases (51.9%) and most were an autosomal dominant, but some were an autosomal recessive. Both hand and/or feet were involved in 22 cases. Most cases of preaxial polydactyly of the hand combined with central polydactyly of the foot were sporadic and unilateral. All cases of both preaxial and postaxial (polyaxial) polydactyly were inherited and bilateral. Two pairs of sisters had the same clinical features. The parent (mother or father) also had the same deformities in the inherited cases.
Three hundred and thirty feet in 265 patients with polydactyly of the foot were classified on the basis of ray involvement and the level of duplication. Anatomic differences in bony structures according to x-ray and operative findings, external appearance of involved digits, associated anomalies, and familial incidence were studied. In medial-ray polydactyly, bilateral occurrence was common, and a higher frequency of associated anomalies was detected. Each involved foot with even the same level of duplication usually had a different morphologic pattern. In central-ray polydactyly, all patients except one had duplications of the second toe, commonly with unilateral involvement. Both components were underdeveloped, with delay in appearance of ossification areas. In two patients, each member of duplication had syndactyly with the neighboring toe, resembling the pattern of polysyndactyly-cleft hand complex. Lateral-ray polydactyl was classified into two new major groups based on ossification pattern and bony alignment: (1) fifty-ray duplication, referring to the medially duplicated supernumerary fifth toe, and (2) sixth-ray duplication, referring to the laterally duplicated supernumerary sixth toe. Fifth-ray duplication was much more frequent than sixth-ray duplication in the Japanese population. Many differences were noted between the two groups of lateral polydactyly. Syndactyly between the fourth and fifth toes was associated only with fifty-ray duplication. Ulnar polydactyly was associated only with sixth-ray duplication. In lateral polydactyly, every patient with bilaterally involved feet had similar groups of polydactyly bilaterally. All the patients in the same family also had similar groups of anomalies. These facts suggest independent etiologic mechanisms for each.
Pathogenetic conditions for polydactyly and its pathogenesis were studied by inducing the condition at a high incidence by incubating fertilized ova of white leghorns and locally cauterizing the limb bud with a bipolar microcoagulator. Polydactyly commonly occurred in about 12 hours of the latter half of the third day after cauterization (5 watts) of the preaxial area of the limb bud. This suggests the involvement of space- and time-specificity under the appropriate strength of such stimulation in the pathogenesis of polydactyly. Most polydactyly involved the first toe. Disturbance in the primordium of the metatarsal bone was believed to be related to the pathogenesis. Many reductive complex malformations resembling polydactyly were seen, and the repairing mechanism of these malformations was similar to that of polydactyly. Thus, it seems that the repairing mechanism is oriented to acquiring the proper number of toes and that acquisition of the first toe becomes particularly dominant, resulting in a tendency for polydactyly in the first toe.
A spontaneous postaxial polydactyly, similar to type B in humans, was found in a partially inbred ICR mouse strain. The supernumerary digit could be detected grossly as early as day 14 of gestation. The incidence of polydactyly decreased with increasing gestational age. All-trans retinoic acid (RA) administered on day 10 or 11 of gestation, but not on day 9, increased the incidence of polydactyly at each gestational day examined. The day 18 levels of polydactyly were greatest after day 10 treatment. No clear dose-response relationship was observed in term fetuses following treatment on day 9, 10, or 11. RA administered on day 10 produced extra digits which were morphologically more advanced than those in the untreated controls. RA, given to the inbred C57B1/10 strain, produced low levels of polydactyly if administered on day 9, but not on day 10 or 11. F1 embryos, from reciprocal crosses between the two strains, were intermediate in response to RA. On day 14, cell death in the postaxial marginal mesoderm was apparent in all protopolydactylous embryos examined, whether treated or untreated. The supernumerary digits varied in size on day 14. The smaller digits appeared to be filled with necrotic mesodermal cells, whereas the larger digits had a necrosis-free area. The size of the extra digit on day 14 seemed to be the most important factor in the persistence of the digit until day 18.
Attempts to study the genetics of human thumb polydactyly have been hampered by lack of awareness of the extremely varied expression of upper limb preaxial anomalies. It has been appreciated that thumb polydactyly could range from a broadened distal phalanx to complete duplication of the entire thumb. Most cases are sporadic and unilateral, but rare familial cases with wide variability and occasional nonpenetrance have been described. Four unrelated families are described who have thumb polydactyly as part of the range of expression for a dominant gene that is frequently associated with absence of thenar intrinsic muscles and flexor pollicis longus with inability to flex the thumb across the palm (the Fromont anomaly). These families and previous literature reports suggest that expression of the gene can range from thumb hypoplasia (most commonly the Fromont anomaly) to triphalangeal thumb or thumb polydactyly. As a consequence of this experience, we urge that parents, siblings, and other close relatives of patients born with thumb polydactyly be carefully examined for mild degrees of thumb hypoplasia or any other thumb anomaly, and that these findings be considered when providing recurrence risk counseling.
The few anatomical findings summarized in the literature have now been expanded by our own anatomical dissections on four hands of still-born infants with postaxial polydactyly, and by intra-operative microsurgical investigations of 25 polydactylous hands. New experimentally-based knowledge of embryology helps interpret the morphogenesis and specific anatomy of polydactyly. It can be postulated that both the location and definite form of polydactyly are a function of the location and extent of initial excessive cell proliferation and disturbance of cell necrosis in the hand blastema. The conclusive discussion of special findings regarding anatomical structures shows regular pattern formations which lend themselves to a broader classification. The classification of malformations of the hand by Temtamy and McKusick was used as a framework for the classification of polydactyly, whether it was existing as an isolated form or as part of a syndrome. The osteological types I to VI found by Wassel in thumb duplication are confirmed by our anatomical findings. Special coding of anatomical findings enabled us to identify four variants and three forms, depending on the development of the digital palmar arteries and nerves. For the triphalangeal pre-axial fingers and the post-axial fifth finger, the five osteological types described by Müller and those described by Duhamel are increased to ten. Comparison with our anatomical findings shows four variants of these osteological types. For post-axial polydactyly, types XI through XIV, existing in three variants, have been defined.
The authors present an unusual case of polydactyly of the foot in an otherwise healthy adult male. The modern literature describing polydactyly of the foot is reviewed, as well as a review and critique of various classification schemes for foot polydactyly deformities. The authors applied the classification criteria of Blauth and Olason to an atypical case and to other varied, yet typical, presentations of polydactyly of the foot in adults. Nonsurgical and surgical treatment options are reviewed, and a rational treatment plan is proposed based upon use of the classification scheme. They then apply the management plan for symptomatic polydactyly of the foot to the unusual case, and make recommendations for surgical management of this deformity.
The histopathology of growth cartilage of long bones was studied in two cases of chondroectodermal dysplasia (Ellis-Van Creveld syndrome), a case of short-rib polydactyly (SRP) type I (Saldino-Noonan syndrome), three cases of short-rib polydactyly (SRP) type III (Verma-Naumoff syndrome), and a case with polydactyly without other skeletal abnormalities but with visceral malformations. The lesions were qualitatively similar in chondroectodermal dysplasia and SRP I: regular concave ossification line, short, slightly irregular columns, regularly dispersed hypertrophic chondrocytes. In SRP III, the ossification line was irregular and the hypertrophic cells had a discontinuous distribution in clusters. No amylase resistant PAS intracytoplasmic inclusions were found. Short, slightly or markedly irregular primary trabeculae, some of them with wide cartilaginous cores, tongue prolongations and islands of cartilage situated along the periost were found in chondroectodermal dysplasia, SRP I and III. The case of polydactyly without other skeletal abnormalities had a normal morphology of the growth plate. These data suggest that there is a relationship between chondroectodermal dysplasia and SPR type I, and that SRP type III is distinct from SRP type I.
In a Japanese family, a propositus and his mother had crossed polydactyly type I. A maternal grandaunt also had preaxial polydactyly of the feet. The findings that both of the mother and son had the identical type of polydactyly are consistent with an autosomal dominant inheritance with variable expressivity. Other explanations include X-linked recessive inheritance, polygenic inheritance, and a chance occurrence of the 2 different kinds of polydactyly.
Using data from the Spanish Collaborative Study of Congenital Malformations (ECEMC), we tested the hypothesis of Carey et al. (Proc Greenwood Genet Cent 9:95, (1990) on maternal diabetes and preaxial polydactyly of feet in infants born to diabetic mothers. Our results seem to confirm their suggestion, although the hallucal type of preaxial polydactyly that they described seems to be much less frequent. Nevertheless, a high risk exists (OR = 24.60, P = 0.0004) for preaxial polydactyly of the feet in relation with other types of birth defects or postaxial polydactyly. This analysis shows the importance of clinical observations for epidemiologists, because such observations constitute hypotheses and provide actual issues for study, and clinicians will get epidemiological confirmation for their individual observations and hypotheses.
We describe four cases with signs resembling those of Meckel syndrome. Two cases demonstrated postaxial polydactyly; one case, preaxial polydactyly; and one case, pre- and postaxial polydactyly. Since there is at least one other reported case with preaxial polydactyly, it may be a rare sign of the Meckel syndrome. In all four cases, various degrees of bowing of the long tubular bones were observed. Since at least two cases exhibited typical Meckel syndrome and since in a few further reported cases X-ray examination revealed bowing of long tubular bones, this sign is considered to be a further, hitherto not well recognized sign of the Meckel syndrome, and not grounds for delineation of a new syndrome. An extensive review of the literature revealed, that shortened and bowed extremities may be present in about one-sixth of all cases with Meckel syndrome.
Polydactyly has an incidence in the American Indian twice that of Caucasians. A minimum estimate of this incidence is 2.40 per 1,000 live births. Preaxial type 1 has an incidence three to four times that reported for Caucasians or Negroes. The overall sex ratio in Indians is distorted with more males affected than females. The preaxial type 1 anomaly has a strong predilection for the hands and always is unilateral in contrast to postaxial type B where more than one-half are bilateral. The evidence to date, consisting of varying incidences of specific types of polydactyly among American whites, Negroes, and Indians in varying enviroments, suggests different gene-frequencies for polydactyly in each population. The incidence in Indians with 50% Caucasian admixture suggests that the factors controlling polydactyly are in large part genetically determined. Family studies and twin studies reported elsewhere offer no clear-cut genetic model which explains the highly variable gene frequencies.
OBJECTIVE: To investigate the clinical characteristics of a fetus with Short-rib thoracic dysplasia 8 with or without polydactyly (SRTD8) due to variants of DYNC2I1 gene. METHODS: A fetus identified to have short ribs, short long bones, and narrow thorax at 26+1 weeks of gestation at the Women and Children's Hospital of Ningbo University in September 2024 was selected as study subject. The fetus underwent termination of pregnancy at 35+5 weeks of gestation. Clinical data of the fetus were retrospectively collected. Whole exome sequencing (WES) was carried out on fetal tissue, and candidate variants were validated by Sanger sequencing. Difference between the wild type and variant DYNC2I1 proteins was analyzed using AlphaFold v3.0.1 and PyMOL v2.5.6 software. Pathogenicity of the variant was rated based on guidelines from the American College of Medical Genetics and Genomics (ACMG). Using keywords such as "DYNC2I1 gene", previous literature on patients due to biallelic DYNC2I1 gene variants were retrieved from the PubMed databases, CNKI, and Wanfang Data Knowledge Service Platform, and the genetic variant and clinical phenotypes of patients were analyzed. The literature retrieval time was set from the establishment of database to December 31, 2025. This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: 2023-094). RESULTS: Prenatal ultrasound revealed that the fetus had short ribs, short long bones, and narrow thorax at 26+1 gestational weeks. WES and Sanger sequencing revealed that the fetus has harbored compound heterozygous variants of the DYNC2I1 gene, namely c.265_268 (p.Gln89GlyfsTer15) in exon 3 and c.1777C>T (p.Arg593Trp) in exon 14, which were inherited from his father and mother, respectively. Prediction of the DYNC2I1 protein structure suggested that the c.265_268del variant has formed a premature termination codon, which may significantly alter the protein's secondary structure. The c.1777C>T variant may disrupt the electrostatic interaction between Arg593 and Asp729. Based on the ACMG guidelines, the c.265_268del (p.Gln89GlyfsTer15) variant was predicted to be likely pathogenic (PM2_Supporting +PVS1), whilst the c.1777C>T(p.Arg593Trp) variant was rated as uncertain significance (PM2_Supporting+PM3+PP4). Literature search has identified five articles related to biallelic DYNC2I1 variants involving a total of 11 fetuses/patients. Together with the fetus from this study, typical phenotypes included short ribs (6 cases), narrow thorax (6 cases), short limb bones (6 cases), and hand polydactyly (6 cases), and foot polydactyly (5 cases), albeit with significant clinical heterogeneity. A total of 12 genetic variants were identified, among which c.44delC was the most common (16.7%, 4/24), followed by c.1777C>T, c.2246C>T, and c.2305G>A (each accounting for 12.5%). No mutational hotspot was identified. CONCLUSION: The c.265_268del (p.Gln89GlyfsTer15) and c.1777C>T (p.Arg593Trp) compound heterozygous variants of the DYNC2I1 gene probably underlay the pathogenesis of SRTD8 in this fetus. This study has enriched the mutational spectrum of the DYNC2I1 gene and facilitated etiological diagnosis and treatment of DYNC2I1-related diseases.
Clinicopathologic examination of eight patients with asphyxiating thoracic dysplasia (Jeune; ATD) disclosed two different types, which were designated as type 1 and type 2. Type 1 ATD was characterized by the presence of radiologically irregular metaphyseal ends and histopathologically irregular cartilage bone junction with patchy distribution of physeal zone of hypertrophy. Type 2 ATD showed radiologically smooth metaphyseal ends and histopathologically diffusely retarded and disorganized physes with smooth cartilage bone junctions. Examination of four patients with the "Verma-Naumoff" short rib-polydactyly syndrome showed many radiologic and pathologic features similar to those of type 1 ATD. Differential diagnosis of these three osteochondrodysplasias is discussed along with chondroectodermal dysplasia (Ellis-van Creveld), short rib-polydactyly syndrome type 1 (Saldino-Noonan), short rib-polydactyly syndrome type 2 (Majewski), and the new short rib syndrome reported by Beemer et al [1983].
Six cases of the McKusick-Kaufman syndrome (MKS), including two cases that were diagnosed prenatally, were studied. Review of the 54 previously described cases indicates that postaxial polydactyly and hydrometrocolpos in female patients are the hallmark features of this entity. Other manifestations, such as malformations of gastrointestinal, cardiovascular, and ophthalmic structures, occur less consistently. Affected children require careful medical follow-up. Recurrence of hydrometrocolpos following surgical repair may lead to serious sequelae, such as chronic renal failure. We believe that MKS is a distinct panethnic genetic entity, inherited in an autosomal recessive fashion, and that the diagnosis should be made only in female patients with hydrometrocolpos and polydactyly or in male patients with polydactyly who have an affected female relative.
The authors present a new classification of polydactyly based on radiomorphological alterations. The malformations are defined in two directions, as in a system of coordinates. The longitudinal arrangement is based on the pathogenetic principle of bifurcation of a finger or a toe ray from distal to proximal. We accordingly divided polydactylies into five types: distal phalanx, middle phalanx, proximal phalanx, metacarpal or metatarsal, carpal or tarsal. The transverse arrangement indicates which rays are involved. All polydactylies, including the special forms such as rudimentary manifestations, triphalangism, and multiple duplications, can be incorporated into this simple basic scheme. Depending on their characteristics, the special forms are further subdivided, e.g., into a distal or proximal phalanx type with simple or double triphalangism, or a tarsal type with third-degree duplication and first-degree aplasia. Numerous radiological examples and schematic drawings illustrate the classification. The advantage of the classification is that it depends exclusively upon the skeletal finding and all manifestations are registered according to a simple scheme longitudinally and transversely. This makes them codifiable for the computer and suitable for multicenter studies. The special forms, the rudiment, triphalangism, and multiple duplication, can easily be further subclassified. Moreover, the nomenclature is simple and is oriented to anatomical terminology.