Dandy-Walker malformation with postaxial polydactyly: a new syndrome?

Pierquin Syndrome: Report of a New Case

Pierquin syndrome is a rare genetic entity characterized by the association of Dandy–Walker malformation and postaxial polydactyly. The incidence is uncertain with only six cases previously reported in the literature. In this study, we reported a new case of Pierquin syndrome born from consanguineous parents, characterized by Dandy–Walker malformation, postaxial polydactyly, and congenital heart disease. The case reinforces an autosomal recessive modality of inheritance and expands the phenotypic spectrum of this rare malformation syndrome.

The Meckel-Gruber syndrome gene, MKS3, is mutated in Joubert syndrome

Joubert syndrome (JS) is an autosomal recessive disorder characterized by cerebellar vermis hypoplasia associated with hypotonia, developmental delay, abnormal respiratory patterns, and abnormal eye movements. The association of retinal dystrophy and renal anomalies defines JS type B. JS is a genetically heterogeneous condition with mutations in two genes, AHI1 and CEP290, identified to date. In addition, NPHP1 deletions identical to those that cause juvenile nephronophthisis have been identified in a subset of patients with a mild form of cerebellar and brainstem anomaly. Occipital encephalocele and/or polydactyly have occasionally been reported in some patients with JS, and these phenotypic features can also be observed in Meckel-Gruber syndrome (MKS). MKS is a rare, autosomal recessive lethal condition characterized by central nervous system malformations (typically, occipital meningoencephalocele), postaxial polydactyly, multicystic kidney dysplasia, and ductal proliferation in the portal area of the liver. Since there is obvious phenotypic overlap between JS and MKS, we hypothesized that mutations in the recently identified MKS genes, MKS1 on chromosome 17q and MKS3 on 8q, may be a cause of JS. After mutation analysis of MKS1 and MKS3 in a series of patients with JS (n=22), we identified MKS3 mutations in four patients with JS, thus defining MKS3 as the sixth JS locus (JBTS6). No MKS1 mutations were identified in this series, suggesting that the allelism is restricted to MKS3.

Antenatal presentation of Bardet-Biedl syndrome may mimic Meckel syndrome

Bardet-Biedl syndrome (BBS) is a multisystemic disorder characterized by postaxial polydactyly, progressive retinal dystrophy, obesity, hypogonadism, renal dysfunction, and learning difficulty. Other manifestations include diabetes mellitus, heart disease, hepatic fibrosis, and neurological features. The condition is genetically heterogeneous, and eight genes (BBS1-BBS8) have been identified to date. A mutation of the BBS1 gene on chromosome 11q13 is observed in 30%-40% of BBS cases. In addition, a complex triallelic inheritance has been established in this disorder--that is, in some families, three mutations at two BBS loci are necessary for the disease to be expressed. The clinical features of BBS that can be observed at birth are polydactyly, kidney anomaly, hepatic fibrosis, and genital and heart malformations. Interestingly, polydactyly, cystic kidneys, and liver anomalies (hepatic fibrosis with bile-duct proliferation) are also observed in Meckel syndrome, along with occipital encephalocele. Therefore, we decided to sequence the eight BBS genes in a series of 13 antenatal cases presenting with cystic kidneys and polydactyly and/or hepatic fibrosis but no encephalocele. These fetuses were mostly diagnosed as having Meckel or "Meckel-like" syndrome. In six cases, we identified a recessive mutation in a BBS gene (three in BBS2, two in BBS4, and one in BBS6). We found a heterozygous BBS6 mutation in three additional cases. No BBS1, BBS3, BBS5, BBS7, or BBS8 mutations were identified in our series. These results suggest that the antenatal presentation of BBS may mimic Meckel syndrome.

A new report of mesomelic camptomelia, polydactyly and Dandy-Walker complex in siblings

Two male siblings with several malformations are reported. The anomalies detected in both fetuses were mesomelic camptomelia, postaxial hexadactyly and Dandy-Walker complex. There was only one similar previous report in the literature. This combination could represent a specific pattern of malformation or a new syndrome, with different variants. The parents' consanguinity and the recurrence in a subsequent pregnancy suggest an autosomal recessive inheritance pattern.

Optic nerve coloboma, Dandy-Walker malformation, microglossia, tongue hamartomata, cleft palate and apneic spells: an existing oral-facial-digital syndrome or a new variant?

We report on a female infant with postaxial polydactyly of the hands, preaxial polydactyly of the right foot, cleft palate, microglossia and tongue hamartomata consistent with an oral-facial-digital syndrome (OFDS). The patient also had optic nerve colobomata, a Dandy-Walker malformation, micrognathia and apneic spells. This combination of clinical features has not been previously reported. This patient either expands the clinical features of one of the existing OFDS or represents a new variant. A review of the literature highlights the difficulties in making a specific diagnosis because of the different classification systems that exist in the literature.

Dandy-Walker malformation with postaxial polydactyly: further evidence for autosomal recessive inheritance

We describe an infant with Dandy-Walker malformation and tetramelic postaxial polydactyly type 1A. Parental consanguinity reinforces previous suggestions for autosomal recessive inheritance.

Telencephalosynapsis (synencephaly) and rhombencephalosynapsis with posterior fossa ventriculocele ('Dandy-Walker cyst'): an unusual aberrant syngenetic complex

Agenesis of the cerebellar vermis (paleocerebellar agenesis) with fusion of the cerebellar hemispheres (rhombencephalosynapsis) is a rare malformation of the central nervous system (CNS). Its combination with synencephaly (telencephalosynapsis), telencephalic ventricular aplasia, aqueductal atresia and cystic fourth ventricle has not yet been described, as far as we know. Here, we report this combination in a 23-weeks' gestation male fetus who was aborted to a 24-year-old diabetic mother. In this fetus with cerebral and cerebellar hemispheric fusion, vermian agenesis was associated with a Dandy-Walker-like posterior fossa cyst, in spite of the fusion of the hypoplastic cerebellar hemispheres. The CNS malformations were further accompanied by dysmorphic facial stigmata such as unilateral atresia of the external ear, ocular hypertelorism and a broad nasal bridge. Preaxial polydactyly and contractures of the upper limbs were the only associated non-cranial abnormalities. Cytogenetic studies revealed a numerically and structurally normal male (46, XY). The malformation complex described in this fetus of a mother with antedating pregnancy diabetes appears to represent a previously undescribed aberrant syngenetic CNS phenotype, some basic teratogenetic aspects of which will be discussed in this paper.

Dandy-Walker malformation and polydactyly: a possible expression of hydrolethalus syndrome

Hydrolethalus syndrome consists of hydrocephalus, polydactyly, micrognathia, midcranial malformations, visceral abnormalities and perinatal lethality. It was first described in Finland, and only a few other cases outside Scandinavia are known. We report the first Hungarian patient who displayed many signs of the syndrome but had no cleft lip and visceral abnormalities. This observation suggests the existence of oligosymptomic hydrolethalus syndrome, and suggests that Dandy-Walker malformation with polydactyly may be a manifestation of the hydrolethalus syndrome.

Familial Dandy-Walker malformation associated with macrocephaly, facial anomalies, developmental delay, and brain stem dysgenesis: prenatal diagnosis and postnatal outcome in brothers. A new syndrome?

Brothers are reported with an apparently new constellation of manifestations including Dandy-Walker complex (DWC), migrational brain disorder, macrocephaly, and facial anomalies. The first brother presented at birth, the second was detected prenatally with DWC and the pregnancy terminated. Fetal brain histopathology showed DWC associated with brainstem dysgenesis. Inheritance is likely autosomal or X-linked recessive. An extensive review of the differential diagnosis of DWC is provided.

Joubert syndrome: a review

We review 72 previously reported and 29 new patients with the possible diagnosis of Joubert syndrome. We define diagnostic criteria for this syndrome and present the data available in 94 patients that fulfill our criteria. We present the data regarding the clinical, neuroradiological, and ophthalmological manifestations and the prognosis of these 94 patients. We propose a classification of the patients with this diagnosis in 2 groups: those with retinal dystrophy and those without. Retinal dystrophy runs true in families and was never absent when renal cysts were reported.