Possible genetic heterogeneity in the Saethre-Chotzen syndrome

Saethre-Chotzen syndrome is an autosomal dominant acrocephalosyndactyly syndrome whose gene has been assigned to chromosome 7p. Cytogenetic and linkage analyses have enabled the interval encompassing the disease gene to be delimited to a short region of chromosome 7p15.3–p21.2. Based on the genetic analysis of three unreported families, we confirm the location of the disease gene(s) in the interval defined by loci D7S664 and D7S493 (Z_max = 4.78 at * = 0 at the D7S488 locus) but fail to decide whether one or more disease-causing genes map in this genetic interval. Received: 2 January 1996 / Revised: 21 March 1996     

Surgical method for treatment of syndactyly with osseous fusion of the distal phalanges.

For the interdigital space plasty to correct a syndactyly with fusion of the distal phalanges, we adopted a new operative procedure, covering the exposed distal bone with local rectangular flaps designed transversely on both dorsal and volar surfaces. A full-thickness skin graft from the groin region covers the remaining raw surface. The procedure was performed in six patients, and the flaps measured 6 mm (width) x 12 to 16 mm (length) in four patients, 5 x 15 mm in one patient, and 5 x 18 mm in one patient. Partial necrosis was observed in only one patient, in whom a narrow flap of 5 x 18 mm was used. In the other five patients, however, the results were satisfactory on both external appearance and function during the follow-up period of 3 to 6 years.     

The syndrome associated with the partial D-monosomy

Summary A female child with multiple malformations and 46,XX,Dq-/46,XX chromosomal mosaicism is described. The main data concerning the phenotypes of other partial D-monosomics mentioned in the literature are reviewed. Despite the variability of clinical picture in these patients it is possible to delineate at least one distnct syndrome associated with partial monosomy D. The completeness of clinical picture as well as of the symptoms vary from case to case. The most typical while non constant somatic symptoms of this syndrome are: absence of the thumb and of the 1st metacarpal bone combined with the fusion of the 4th and 5th metacarpal bones; skull/brain defects of the arrhinencephaly/trigonocephaly type; colobomata; anal atresia. Sometimes retinoblastoma occurs. It is likely that the chromosome involved in this syndrome is D1(13) chromosome.

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Zusammenfassung Ein Mädchen mit multiplen Mißbildungen und dem Mosaik 46,XX,Dq-/46,XX wird beschrieben. Bie dieser Gelegenheit werden die wesentlichen Daten über den Phänotyp anderer Fälle mit partieller D-Monosomie aus der Literatur zusammengefßt. Trotz der Variabilität des klinischen Bildes ist es möglich, wenigstens ein ausgeprägtes Monosomie D-Syndrom abzugrenzen. Die Vollständigkeit des klinischen Bildes und der Symptome variiert von Fall zu Fall. Die typischsten, wenn auch inkonstanten Symptome sind die folgenden: Fehlen des Daumens und des Os metacarpale 1; Verschmelzung des 4. und 5. Metacarpale; Schädel-Hirn-Defekte vom Arrhinencephalie-Trigonocephalie-Typ; Kolobome; Analatresie. In mehreren Fällen kommt auch ein Retinoblastom vor. Wahrscheinlich ist das betreffende Chromosome D1 (13).

     

The distal aorta in the Marfan syndrome

Prolonged survival of patients with Marfan syndrome after aortic root replacement has led to an increased number of patients with aortic complications beyond the root. Elective replacement of the aortic root removes the most important predilection site for aneurysms, but the distal aorta remains at risk. Predictors for aortic growth and adverse events in the distal aorta include aortic diameter, aortic distensiblity, previous aortic root replacement, hypertension and aortic regurgitation. After aortic dissection, the initial false lumen diameter is an independent predictor for late aneurysm formation. Although there are a few reports of short-term success after endovascular stent grafting of the descending thoracic aorta, stent grafting in patients with Marfan syndrome is not recommended unless intervention is clearly indicated and the risk of conventional open surgical repair is deemed prohibitive. Optimal long-term outcome demands lifelong radiographic follow-up and medical treatment with β-blocker therapy. After aortic dissection rigorous antihypertensive medication is of utmost importance. Losartan, an angiotensin II type I receptor antagonist, might offer the first potential for primary prevention of clinical manifestations in Marfan syndrome, but the results of clinical trials have to be awaited. (Neth Heart J 2008;16:382-6.)     

Aplasia of the thumbs and great toes as the outstanding feature of Yunis and Varon syndrome. A new entity. A new observation

Aplasia of the thumbs and great toes, and aplasia of terminal and dysplasia of middle phalanges with absence of nails were noted in the child of related parents, who died at the age of 3 months from cardiorespiratory insufficiency. This is the 7th case of an (AR) genetic syndrome called after Yunis and Varon.     

The false and the true bifid condyles

The bifid mandibular condyle has been described as a condition of unknown ætiology and uncertain pathogenesis. Many see it as the product of accidental trauma or forceps delivery, with the two heads occurring one behind the other in the sagittal plane.

In bioanthropological literature, “bifid condyle” often describes pitting in the sagittal plane, dividing the condyle mediolaterally.

We examined 38 male and 16 female pre-European-contact Pacific islanders’ adult mandibles, and 24 male and 29 female modern Indian mandibles, recording frequency, prominence and position of any condylar groove in both coronal and sagittal planes.

We report the tenth known case of a bilaterally-bifid condyle. A groove was found almost twice as likely to occur on the left condyle of the Indians than of the Pacific Islanders, but equally likely to occur on the right side of both groups. That same finding applied to males and females.

In order to avoid terminological ambiguity, we suggest that the term “bifid condyle” should be reserved for describing multiple condyles in the sagittal plane only – the true bifid condyle.

An hypothesis is offered for the occurrence of the groove in the sagittal plane.     

Syndactyly of the toes

The experience gained through the management of 43 patients with syndactyly of the toes is presented. The incidence appears to be similar to that of syndactyly of the fingers. Type 1 syndactyly, or zygodactyly, always presented itself as a cosmetic problem; its correction is occasionally indicated and the procedure used is discussed. Type 2 syndactyly, or polysyndactyly, represents a functional problem and deserves surgical correction. My negative experience with the more complex procedures described for the correction of polysyndactyly is presented as well as my satisfaction with the simpler procedures. Suggestions for management are offered.     

Evidence for locus heterogeneity in acrocephalosyndactyly: a refined localization for the Saethre-Chotzen syndrome locus on distal chromosome 7p--and exclusion of Jackson-Weiss syndrome from craniosynostosis loci on 7p and 5q.

Craniosynostosis (premature fusion of the skull sutures) occurs as a clinically heterogeneous group of disorders, frequently involving digital abnormalities. We have previously provisionally assigned the gene for one such condition, Saethre-Chotzen syndrome (ACS III), to chromosome 7p. Linkage analysis is now reported between ACS III and dinucleotide repeat loci on distal 7p. The maximum lod scores, Zmax, were 5.57 at a recombination fraction of .05, with D7S488, and 4.74 at a recombination fraction of .05, with D7S493. Only weak linkage, not reaching significance, was found with distal markers (D7S513 and afm281vc9) and a proximal marker (D7S516). Multipoint analysis shows that the disease locus lies between D7S513 and D7S516. Analysis of individual recombinants shows that the most likely position is between D7S493 and D7S516. Linkage data in regard of Jackson-Weiss syndrome demonstrate that this autosomal dominant form of acrocephalosyndactyly does not map to the ACS III region on 7p or to the acrocephalosyndactyly locus on 5q (Boston type). These findings underline the genetic heterogeneity among the different clinical conditions manifesting with acrocephalosyndactyly.     

Apert syndrome with partial preaxial polydactyly.

Acrocephalosyndactyly type I or Apert syndrome is characterized by craniosynostosis, particular dysmorphic features and abnormalities of the hands and feet. Rarely, polydactyly of the toes has been reported, and in this event the diagnosis of Carpenter syndrome must be discussed. A case of atypical Acrocephalosyndactyly type I syndrome with partial preaxial polydactyly is reported. Despite this preaxial polydactyly a diagnosis of Apert syndrome consecutive to a new mutation was made, and the possibility of recurrence considered to be highly improbable.