Postaxial acrofacial dysostosis syndrome with microcephaly, seizures and profound mental retardation

Miller (Genee-Wiedemann) syndrome represents a clinically and biochemically distinct subgroup of postaxial acrofacial dysostosis associated with partial deficiency of DHODH

Biallelic mutations in the gene encoding DHOdehase [dihydroorotate dehydrogenase (DHODH)], an enzyme required for de novo pyrimidine biosynthesis, have been identified as the cause of Miller (Genée-Weidemann or postaxial acrofacial dysostosis) syndrome (MIM 263750). We report compound heterozygous DHODH mutations in four additional families with typical Miller syndrome. Complementation in auxotrophic yeast demonstrated reduced pyrimidine synthesis and in vitro enzymatic analysis confirmed reduced DHOdehase activity in 11 disease-associated missense mutations, with 7 alleles showing discrepant activity between the assays. These discrepancies are partly explained by the domain structure of DHODH and suggest both assays are useful for interpretation of individual alleles. However, in all affected individuals, the genotype predicts that there should be significant residual DHOdehase activity. Urine samples obtained from two mutation-positive cases showed elevated levels of orotic acid (OA) but not dihydroorotate (DHO), an unexpected finding since these represent the product and the substrate of DHODH enzymatic activity, respectively. Screening of four unrelated cases with overlapping but atypical clinical features showed no mutations in either DHODH or the other de novo pyrimidine biosynthesis genes (CAD, UMPS), with these cases also showing normal levels of urinary OA and DHO. In situ analysis of mouse embryos showed Dhodh, Cad and Umps to be strongly expressed in the pharyngeal arch and limb bud, supporting a site- and stage-specific requirement for de novo pyrimidine synthesis. The developmental sensitivity to reduced pyrimidine synthesis capacity may reflect the requirement for an exceptional mitogenic response to growth factor signalling in the affected tissues.

A variant or a "new" postaxial acrofacial dysostosis syndrome

In this paper, we report a boy with remarkable phenotype and noteworthy radiographic abnormalities. He presented with distinctive facies, mesomelic shortening and asymmetry of the extremities, symmetrical ulnar and fibular ray absence in the hands and feet, with unique hypoplastic/dysplastic radiographic abnormalities. His mental development was normal. We believe that he represents a previously unreported form of the postaxial acrofacial dysostosis syndrome.

A new observation of two cases of acrofacial dysostosis type Genée-Wiedemann in a family--remarks on the mode of inheritance: report on two sibs

We report on a Yugoslavian sibpair with postaxial acrofacial dysostosis type Genée-Wiedemann with some novel signs which broaden the spectrum of this syndrome. The manifestations of the present cases are compared with those of the previously described patients. Life expectancy, change of symptoms over time, and the mode of inheritance are discussed.

Acrofacial dysostosis of unknown type: nosology of the acrofacial dysostoses

We describe a stillborn girl with an unclassified form of mandibulofacial dysostosis, a postaxial defect of the right, and a preaxial defect of the left hand. The Nager syndrome is characterized by preaxial limb defects, whereas the Genée-Wiedemann syndrome (= Miller syndrome) by postaxial limb defects. We briefly review the established acrofacial dysostoses (AFD) and discuss the position of our case in the current classification.

Acrofacial dysostoses: review and report of a previously undescribed condition: the autosomal or X-linked dominant Catania form of acrofacial dysostosis

The acrofacial dysostoses (AFDs) are a heterogeneous group of disorders combining defects of craniofacial and limb development. The predominantly preaxial form is called Nager AFD, the predominantly postaxial form of AFD (POADS) is also known as the Genée-Wiedemann or Miller syndrome. The former appears to be about twice as common as the latter with well-documented autosomal dominant and recessive occurrences in both conditions. Only 1 AD occurrence of POADS is known, but 5 sets of sibs are suggestive of AR inheritance. Heterogeneity of apparently nonsyndromal AFD of both types is powerful support for the hypothesis that the AFDs are polytopic field defects arising during blastogenesis. Six other previously described forms of AFD include the AFD syndrome of Kelly et al. (AR), the Rodríguez or Madrid form of AFD (AR or XLR), the Reynolds or Idaho form of AFD (AD), the Arens or Tel Aviv type of AFD (AF?), the presumed AR AFD syndrome of Richieri-Costa et al., and the AD Patterson-Stevenson-Fontaine syndrome. Here we review the AFDs and report on a previously apparently undescribed autosomal or X-linked dominant form of AFD with mental retardation in a Sicilian mother and her 4 sons.

Postaxial acrofacial dysostosis: report on two patients

We report on 2 patients with the postaxial acrofacial dysostosis (AFD) syndrome. One patient was an isolated case; the other had an equally affected brother previously described [Richieri-Costa and Guion-Almeida, 1989]. Recurrence in sibs suggests autosomal recessive inheritance.

New form of postaxial acrofacial dysostosis?

We report on a 2-month-old Sephardic Jewish girl with bilateral and symmetrical deficiency of the fifth digital rays of all 4 limbs, combined with severe deformations and other malformations of the limbs. These findings were associated with orofacial malformations, as well as with visceral anomalies differing from those found in other postaxial deficiency syndromes. Parents were closely consanguineous. We assume this patient represents a new form of postaxial acrofacial dysostosis.

Miller syndrome (postaxial acrofacial dysostosis): further evidence for autosomal recessive inheritance and expansion of the phenotype

A sibship with postaxial acrofacial dysostosis syndrome (Miller syndrome) is reported. In addition to the characteristic facial and limb defects, previously undescribed anomalies, including midgut malrotation, gastric volvulus, and renal anomalies, are recorded.