Dandy-Walker syndrome is a congenital brain malformation that consists of the triad hypoplasia or absence of the vermis, upward displacement of the falx, lateral sinuses, and torcular, and a large, thin walled retrocerebellar cyst formed by the roof of the fourth ventricle. It is frequently associated with disorders of other areas of the central nervous system including absence of the corpus callosum, and malformations of the heart, face, limbs, fingers and toes. Symptoms, which often occur in early infancy, include slow motor development and abnormally rapid increase in head circumference with bulging at the back of the skull. In older children, symptoms of increased intracranial pressure such as irritability, vomiting, and convulsions, and signs of cerebellar dysfunction such as unsteadiness, lack of muscle coordination, or jerky movements of the eyes may occur. There may also be problems with the nerves that control the eyes, face and neck, and abnormal breathing patterns.
The critical region associated with Dandy-Walker syndrome was defined through physical mapping of 3q2 interstitial deletions in several individuals with the disease. This 7-Mb region was found to encompass two genes - ZIC1 and ZIC4, both of which encode members of the ZIC family of C2H2-type zinc finger proteins.
[See also: Palestine > Al-Gazali et al. 1996].
Koul et al. (2000) reported the diagnosis of neurofibromatosis type 1 in monozygotic twins with Dandy-Walker syndrome. The twins, both males, were born at term to non-consanguineous parents. At delivery they were noted to be monozygotic twins as there was a single placenta. There were no antenatal or perinatal complications. As motor and mental developmental delay was noticed by the parents, these children at the age of 32-months were referred to the authors' care for neurological evaluation, which revealed marked motor delay (head control at nine months, sitting at one year, and just standing with support when seen) and no speech development. Examination revealed head circumference at the 50th percentile but both weight and height were below the third percentile. Both children had dysmorphic features which were not descriptive of any syndrome, including prominent forehead, hypotelorism, low set ears and prominent occiput. In addition to these features, they had café-au-lait spots seen more on their trunks with few of 5 cm2 in size, along with few depigmented spots. A diagnosis of neurofibromatosis type 1 was made on the bass of the presence of the features of café-au-lait, microcephaly and short stature. Routine investigations, including blood count, liver and renal function tests, nerve conduction studies and brainstem auditory evoked potential, and karyotyping were normal. In both children, CT scan of the brain revealed typical features of Dandy-Walker syndrome which were cerebellar aplasia, cystic dilatation of the fourth ventricle and enlarged posterior fossa. In addition, one twin had hydrocephalus as well. Koul et al. (2000) suggested an underlying genetic basis for this unique association of neurofibromatosis type 1 with Dandy-Walker syndrome in monozygotic twins.
Al-Gazali et al. (1996) reported a child, born to unrelated parents of Palestinian-Jordanian origin, with typical features of Meckel syndrome in whom both encephalocele and Dandy Walker malformation (DWM) existed. This female child, as well as two previous females born to the family, were born with posterior encephalocele, polycystic kidneys and no polydactyly. Both died a few hours after birth. At birth, the propositus was noted to also havewide sutures with an occipital encephalocele. CT scan of the brain showed hypoplastic cerebellar hemispheres, an absent vermis and a very large posterior fossa cyst communicating with the fourth ventricle, and high attachement of the tentorium. Renal ultrasound showed hugely enlarged hyperchogenic kidneys on both sides with loss of corticomedullary differentiation. The baby died on the second day of life.
El Awad (1992) calculated the overall incidence of infantile hydrocephalus in the south-western region of Saudi Arabia as 0.81/1000 between January 1988 and December 1990. Five of these infants showed Dandy-Walker malformation (8.2%).
Ohaegbulam and Afifi (2001) studied the incidence of DWS in a defined Saudi Arabian population of military personnel and their dependants during an 11-year period (1989-1999) from a cohort of 45,274 live births. Ohaegbulam and Afifi (2001) recorded an incidence of 1.0 DWS case per 100,000 live births per year. The incidence by sex per 100,000 live births per year was 1.24 for males and 0.78 for females. DWS formed 3.5% of studied cases of infantile hydrocephalus.
Alorainy (2006) reviewed and analyzed the MRI studies on 808 pediatric patients (aged 3 days to 15 years) over a 3-year period. A total of 114 congenital cerebral malformations were identified in 86 of these patients via MRI. Three patients were identified with Dandy Walker malformation.
Kurdi et al., (2009) described a 2-month old boy with a rare Dandy Walker malformation associated with progressive heart failure secondary to hypertrophic cardiomyopathy. The child died at the age of 7 months.
Al Talabani et al. (1998) studied the pattern of major congenital malformations in 24,233 consecutive live and stillbirth at Corniche hospital, which is the only maternity hospital in Abu Dhabi, between January 1992 and January 1995. A total of 401 babies (16.6/1,000), including 289 Arabs, were seen with major malformation. Single gene disorders accounted for 24% of the cases, 76% were due to autosomal recessive disorders. In their study, Al Talabani et al. (1998) observed two cases of Dandy-Walker syndrome in consanguineous families from the United Arab Emirates. Recurrence of the disease was reported in other members of the families. Al Talabani et al. (1998) concluded that their study was very close to representing the true incidence of congenital abnormalities in the whole United Arab Emirates, as they investigated over 98% of deliveries in Abu Dhabi, the capital of United Arab Emirates.
[See also: Palestine > Al-Gazali et al. 1996]