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Dandy-Walker continuum, which includes Dandy-Walker malformation, vermian hypoplasia, and Blake pouch cyst, is among the most commonly diagnosed posterior fossa malformation by fetal magnetic resonance imaging (MRI). The objective of our retrospective study was to evaluate fetal and postnatal MRI scan and clinical outcomes. Seventy-two patients were identified; 40 patients had postnatal imaging and follow-up (7 Dandy-Walker malformation, 26 vermian hypoplasia, and 7 Blake pouch cyst). Although all patients with Dandy-Walker malformation required ventriculoperitoneal shunts and 66% were intubated at birth, none required tracheostomy tube and 2 of 5 surviving children had no neurologic deficits. Vermian hypoplasia was strongly associated with genetic conditions and cardiac malformations; odds of not ambulating normally were 12 times greater if a syndrome or injury was present. Echocardiogram and genetic screening are recommended with vermian hypoplasia. There is a risk for epilepsy in both Dandy-Walker malformation and vermian hypoplasia. Blake pouch cyst can be complicated by hydrocephalus, but outcome is favorable.

Objective: Dandy-Walker syndrome (DWS) is a rare neurologic multi-entity malformation. This review aimed at reporting its main nonneurologic comorbidities. Methods: Following PRISMA guidelines, search in Medline was conducted (2000-2014, keyword: dandy-walker). Age, sex, country, DWS type, consanguinity or siblings with DWS, and recorded coexistent conditions (by ICD10 category) were extracted for 187 patients (46.5% male, 43% from Asia) from 168 case reports. Results: Diagnosis was most often set in 12 years old (27.8%). One-third of cases had a chromosomal abnormality or syndrome (n = 8 PHACE), 27% had a cardiovascular condition (n = 7 Patent Ductus Arteriosus), 24% had a disease of eye and ear (n = 9 cataract); most common malignancy was nephroblastoma (n = 8, all Asian). Almost one-fifth had a mental illness diagnosis; only 6.4% had mild or severe intellectual disability. Conclusion: The spread of comorbidities calls for early diagnosis and multidisciplinary research and practice, especially as many cases remain clinically asymptomatic for years.

Cerebellar vermian hypoplasia in the context of Dandy-Walker complex is a relatively common disorder associated with a variety of cognitive and behavioral deficits in addition to impairment in motor control. Few studies, however, have examined the neuropsychological profiles of children with isolated hypoplasias of the cerebellum. Herein, we report a 6-year-old girl with Dandy-Walker continuum presenting with mild mental retardation and an inability to produce intelligible speech, despite adequate comprehension of single items and simple instructions. She was able to articulate vowels but not consonants, and fine motor function was deficient. Visual memory was intact for single items but not for multiple items, and visuospatial perception was impaired. An inability to form intelligible speech is not typically reported in cases of isolated vermian hypoplasia. The case extends our knowledge of the phenotypes associated with cerebellar hypoplasia and its relation to fine motor and articulatory control.

We report a case carrying a de novo interstitial deletion of chromosome 3q22-q25. The clinical phenotype of this case included blepharophimosis/ptosis/epicanthus inversus syndrome, Dandy-Walker malformation, and global developmental delay. Contiguous heterozygous deletion of FOXL2, ATR, ZIC1, and ZIC4 was postulated as the causative mechanism of the clinical phenotype. The association of blepharophimosis, ptosis, and epicanthus inversus syndrome with developmental delay or mental retardation may be an indication for the use of brain imaging and chromosomal analysis capable of detecting chromosomal rearrangements encompassing several candidate genes.

An enlarged cisterna magna can be identified during routine ultrasound screening in the second half of pregnancy. It is important to be able to give an accurate prognosis. We evaluated the developmental outcome of these children. A total of 29 fetuses with a large cisterna magna identified in utero were compared to 35 children with a normal fetal ultrasound. The children were evaluated by the Gesell Developmental Schedules and the Peabody Developmental Motor Scale. The study group showed a significantly worse performance in the Gesell test. However, the overall performance for both groups was within normal limits. Four children in the study group had a borderline developmental quotient. Both groups performed similarly in the Peabody test. Walking age was significantly delayed in the study group. Children with an enlarged cisterna magna may be at risk for mild developmental delay. In cases of nonisolated enlargement of the cisterna magna, the outcome may be guarded.

This report is a neuropathological description of posterior cerebellar vermis agenesis/hypoplasia at midgestation. This defect was demonstrated by prenatal ultrasound in four 21- to 24-week-old fetuses. Neuropathological findings were characterized macroscopically by hypoplasia of the posterior vermis with normal cerebellar hemispheres and brainstem; hypoplasia of the posterior vermian lobules 6 to 10, mildly cystic dilatation of the ventricular cavity, and a flat profile of the roof of the fourth ventricle also were demonstrated. Microscopically, a hypercellular and abnormally located germinal matrix and abnormal migration of external granule cell precursors into the meningeal tissue above the outer surface of the cerebellum were found. These abnormalities might result in delayed growth and foliation of the posterior vermian lobules. This feature might be the neuropathological pattern of the early stage of the Dandy-Walker continuum, although it cannot be excluded as a consequence of a primary developmental failure of the vermal primordium.

In 135 children (aged 3 months to 15 years) with structural defects of the central nervous system found on magnetic resonance imaging, agenesis of the corpus callosum was evident in 7. The etiology of agenesis of the corpus callosum has been established in four children: partial trisomy of chromosome 13, partial duplication of the long arm of chromosome 10, Aicardi's syndrome, and intracranial bleeding during the fetal period as a result of injury. Agenesis of the corpus callosum coexisted with a Dandy-Walker malformation in one other patient, which suggests a genetic etiology. In spite of these variable etiologies, dysmorphic features were identified in all seven patients, as was psychomotor retardation. Epileptic seizures had occurred in six patients, and all manifested abnormalities on neurologic examination. ( J Child Neurol 2000;15:401-405).

Molybdenum cofactor deficiency leads to combined deficiency of sulfite oxidase, xanthine dehydrogenase, and aldehyde oxidase enzyme activities. The major clinic symptom is intractable seizures seen soon after birth. No definite therapy is available. We report here a newborn with molybdenum cofactor deficiency—associated Dandy-Walker malformation who presented with severe lactic acidosis and intracranial hemorrhage. ( J Child Neurol 2004; 19:155—157).

Fryns syndrome, a multiple congenital anomaly syndrome associated with diaphragmatic defects, craniofacial dysmorphism, distal digital hypoplasia, and neurologic abnormalities, was first described in 1979. This autosomal recessive disorder is usually associated with stillbirth or death immediately after birth. Detailed neurologic findings in the third survivor beyond the neonatal period are reported, and neurologic abnormalities in other cases are reviewed. Initially, hypotonia, areflexia, and weakness were seen. Myoclonus developed immediately after birth and was well controlled with high-dose valproate. Electroencephalography revealed slowing and irregular paroxysmal discharges with spikes and sharp waves that disappeared with time and treatment. Magnetic resonance imaging demonstrated partial agenesis of the corpus callosum, a Dandy-Walker malformation, and progressive cerebral and brainstem atrophy. This syndrome should be considered in patients with unusual facial features and digital abnormalities associated with frequent early myoclonus. (J Child Neurol 1995; 10: 110- 113).

An uncommon but well-recognized occurrence in patients with Dandy-Walker malformation is sudden unexpected death. The mechanism of demise has not been established. We report three patients with Dandy-Walker malformation that experienced sudden unexpected death without uncal or tonsillar herniation, the mechanism usually proposed for demise in such situations. Our findings suggest the possibility of vascular compromise as the cause of the sudden unexpected death in these patients. Early and effective relief of the pressure in the posterior fossa may prevent the occurrence of this catastrophic complication. (J Child Neurol 1995;10:382-384).

Key features of Joubert syndrome include developmental delay, hypotonia, hyperpnea and apnea, oculomotor apraxia, and the presence of the molar tooth sign on axial imaging through the brainstem isthmus—the junction of the pons and mesencephalon. Interestingly, 1 in 10 patients with Joubert syndrome has abnormal cerebrospinal fluid collections misdiagnosed as Dandy-Walker variants. Because of important differences in patient management, genetic counseling, and prognosis between these conditions, we undertook a study to determine if the brainstem isthmus is normal in Dandy-Walker syndrome. Using standard landmarks, we evaluated development of the isthmus in normal subjects and in subjects with Joubert syndrome and Dandy-Walker syndrome. Four of five brainstem measures increased with age in normal subjects. In subjects with Joubert syndrome, the depth and length of the interpeduncular fossa were increased, and the width of the isthmus was decreased. In subjects with Dandy-Walker syndrome, the width of the brainstem isthmus was normal, and the molar tooth sign was absent. Although the pons can be hypoplastic in Dandy-Walker syndrome, we conclude that the pontomesencephalic junction is normal. Thus, the molar tooth sign can effectively distinguish between Joubert and Dandy-Walker syndromes. Genetic heterogeneity or epigenetic factors may account for abnormal cerebrospinal fluid collections in some cases of Joubert syndrome. (J Child Neurol 2001;16:751-758).

Hematologic side effects are rare side effects of treatment with phenytoin. We report a 2-year-old girl who developed reversible thrombocytopenia following treatment with phenytoin. Thrombocytopenia as a side effect of phenytoin treatment has usually been reported in adults and generally occurs 2 to 4 weeks after initiation of therapy. In our case, the thrombocytopenia developed on the 11th day of therapy and resolved 5 days after discontinuation of the phenytoin. (J Child Neurol 1999;14:130-131).

The authors present the second case in the literature of Dandy-Walker malformation associated with occipital meningocele and congenital cardiac defect. This association suggests that the time of origin of this posterior fossa malformation is before the sixth postconception week; however, the pathogenesis remains unsettled. (J Child Neurol 1986;1:64-66)