The tetraphocomelia-cleft palate syndrome in identical twins

Femoral-tibial-synostosis in a child with Roberts syndrome (Pseudothalidomide): a case report

Background

Roberts syndrome (Pseudothalidomide) is a rare birth defect that causes severe bone malformation complex. The bones of the arms, and in some cases other appendages, may be extremely shortened and even absent. The fingers of the hands may be fused. An extreme case results in the absence of the upper bones of both the arms and legs so that the hands and feet appear attached directly to the body. This is called tetraphocomelia.

Case presentation

We report on a two-year-old boy of Austrian origin who manifests a constellation of malformation complex include prenatal and postnatal growth retardation, craniofacial anomalies and defective development of all four extremities. The overall clinico-radiographic features were compatible with Roberts syndrome (Pseudothalidomide). Significant unilateral femoral-tibial synostosis was additional malformation.

Conclusion

Associated malformations and symptoms may be the key factor in the differential diagnosis of neonatal malformation complex. Roberts's syndrome may be genetically transmitted within families as an autosomal recessive trait or may be the result of spontaneous/sporadic changes in the gene. Because the signs of the disorder so closely mimic those caused by the ingestion of thalidomide, the term "pseudo-thalidomide" is frequently used.

In this report we describe total femorotibial fusion in a child manifesting the phenotypic features consistent with Roberts syndrome from a healthy parents but first cousins in Austria. Aggressive medical intervention is of prime importance, as is forthright parental counselling when discussing the possible outcome for these patients.

Mapping of a single locus capable of complementing the defective heterochromatin phenotype of Roberts syndrome cells

Roberts syndrome (RS) is a developmental disorder characterized by tetraphocomelia and a broad spectrum of additional clinical features. Most patients with RS exhibit characteristic cytogenetic phenotypes, which include an abnormal appearance of pericentromeric heterochromatin on metaphase chromosomes, referred to as "heterochromatic repulsion." In the present study, we use complementation of this abnormal cytogenetic phenotype as a means to identify a specific region of the normal human genome capable of rendering phenotypic correction. We screened the entire human genome, using a transient chromosome-transfer assay, and demonstrated complementation exclusively after the transfer of proximal chromosome 8p, a result subsequently confirmed by stable microcell-mediated chromosome transfer. Additionally, homozygosity mapping was used to refine the interval of this complementing locus to 8p21. The results are consistent with the notion that the single gene defect responsible for heterochromatic splaying and developmental abnormalities maps to chromosome 8p21.

Tetra-amelia, lung hypo-/aplasia, cleft lip-palate, and heart defect: a new syndrome?

We report on a family with two sons affected with tetra-amelia, cleft lip-palate, bilateral agenesis of lungs, and heart defects. These two cases support the previous suggestions that this complex entity may indeed represent a new syndrome. However, the mode of inheritance is still not clarified.

Roberts syndrome: a review of 100 cases and a new rating system for severity

Roberts syndrome (RS) is a rare genetic disorder characterized by pre- and postnatal growth retardation, limb defects, and craniofacial anomalies. Affected persons have varying degrees of malformations involving symmetric reduction in the number of digits, and length or presence of bones in the arms and legs. Craniofacial malformations involve hypertelorism, hypoplastic nasal alae, and a high incidence of cleft lip and palate. Familial and sporadic cases have been reported consistent with an autosomal recessive mode of inheritance. Mitotic cells from many individuals with RS display a characteristic cytogenetic phenomenon consisting of repulsion of heterochromatic regions near centromeres, particularly of chromosomes 1, 9, 16, and splaying of the short arms of the acrocentrics and of the distal Yq. Mitosis in RS cells is abnormal in metaphase duration and anaphase progression. Specifically, anaphase figures show a higher degree of chromosomes that are outlying, lagging, or prematurely advancing toward the poles compared to normal controls. RS cells have abnormal nuclear morphology and also show a higher frequency of micronucleation than normal cells, presumably as a result of the abnormal mitotic events during anaphase. Therefore, RS has been interpreted as a human mitotic mutation syndrome which leads to secondary developmental defects. This report reviews 100 cases of RS, summarizes the phenotypic, genetic, cytogenetic, and cell biology findings in Roberts syndrome, and introduces the RS Rating for quantitating severity.

Recurrent tetraamelia and pulmonary hypoplasia with multiple malformations in sibs

A term amelic female infant was born to an apparently nonconsanguineous Arab Moslem couple. This was followed by the birth of 4 normal children. Afterwards, in 2 subsequent pregnancies, 2 amelic fetuses were diagnosed by transabdominal ultrasonography in the 18th and 12th week of gestation. Pregnancies were terminated and on autopsy both amelic fetuses had severe lung hypoplasia and aplasia of the peripheral pulmonary vessels. The first fetus also had apparently low-set ears and micrognathia, whereas the last had hydrocephaly and left cleft lip beside the lung hypoplasia and aberrant pulmonary artery. This appears to be a new autosomal recessive malformation syndrome.

Prenatal detection of Roberts-SC phocomelia syndrome: report of 2 sibs with characteristic manifestations

We describe 2 sibs with Roberts-SC phocomelia syndrome. Although an ultrasound scan performed at 13 weeks of gestation failed to identify specific abnormalities, repeat scan at 17 weeks detected tetraphocomelia. Ultrasonography can reliably detect Roberts-SC phocomelia prenatally; however, serial scans may be needed. Postmortem examination of the proposita confirmed the sonographic findings and also disclosed dysplastic kidneys and ovarian dysgenesis. The degree of phenotypic variation observed between the sibs supports the hypothesis that Roberts syndrome and SC phocomelia represent a single genetic entity.

Roberts syndrome and SC phocomelia. A single genetic entity

A family with three siblings showing different manifestations of Roberts syndrome or SC phocomelia is described. With regard to previously published cases of familial Roberts syndrome and SC phocomelia we conclude that these two syndromes are one and the same genetic entity.

SC phocomelia syndrome, premature centromere separation, and congenital cranial nerve paralysis in two sisters, one with malignant melanoma

Two middle age sisters had most manifestations of the SC phocomelia syndrome including postnatal growth retardation, symmetric limb deficiencies with radial aplasia and absent thumbs, facial anomalies with microcephaly, microphthalmia, hypoplastic nasal alae, and borderline to mild mental retardation. Unusual findings included congenital paralysis of some cranial nerves in both patients and malignant melanoma in the proposita. Cultured lymphocytes from both patients, and skin fibroblasts, Epstein Barr virus-transformed lymphocytes, and tumor cells from the proposita demonstrated premature separation of centromeric heterochromatin (PCS) of many chromosomes, a finding noted previously in the SC phocomelia syndrome and the similar but more severe Roberts syndrome. Extensive overlap of the phenotypes of the sisters and 15 other patients with either syndrome and PCS confirms that these are either allelic conditions or the same disease--designated Roberts-SC phocomelia syndrome. The role of PCS in the syndrome(s) remains uncertain since some patients with the characteristic clinical phenotypes are reported to lack it.