American Journal of Medical Genetics 76:107–110 (1998) Prenatal Diagnosis of Walker-Warburg Syndrome in Three Sibs B. Gasser,1* V. Lindner,1 M. Dreyfus,2 X. Feidt,3 P. Leissner,4 A. Treisser,3 and C. Stoll5 1 Institut de Pathologie, Strasbourg, France Service de Gynécologie 1, Strasbourg, France 3 Maternité-Ecole de Sages Femmes, Strasbourg, France 4 Service de Gynéco-Obstétrique Obernai, Strasbourg, France 5 Service de Génétique Médicale, Centre Hospitalo-Universitaire, Strasbourg, France 2 Walker-Warburg syndrome (WWS) is an autosomal recessive condition characterized by diffuse neurodysplasia, resulting in brain and eye abnormalities. We report on 3 prenatally diagnosed cases of this syndrome born to a consanguineous couple. An ultrasonographic examination showed hydrocephalus at the 27th week of the first pregnancy. Amniocentesis documented a normal male karyotype. The couple opted for termination of the pregnancy but declined an autopsy. Seven months later, hydrocephalus was observed at 20 weeks of the second pregnancy. Termination of pregnancy was performed at the 22nd week. Autopsy of this male fetus showed dilated ventricles, thin cortex, and type II lissencephaly with microscopic evidence of chaotic architecture. Eye examination showed retinal dysplasia. Notwithstanding the lack of demonstrable muscle change, the diagnosis of WalkerWarburg syndrome was made. Ten months later, hydrocephalus was discovered in the third fetus, a female, at 13 weeks of gestation. Termination of pregnancy was performed at 20 weeks. At autopsy, brain, eye, and muscular findings were similar to those of the previous case. In addition, cystic changes and a stenosis of the pyelo-ureteral junction were found in the right kidney. Type II lissencephaly and retinal dysplasia are characteristic of WWS. Muscular dystrophy has been pointed out as an additional abnormality in postnatal cases. By contrast, the lack of demonstrable muscle changes in the fetal period must be emphasized. Those cases illustrate practical prob- *Correspondence to: Bernard Gasser, Institut de Pathologie, 1 Place de l’Hôpital, 67064 Strasbourg Cedex BP 22, France. Received 18 December 1996; Accepted 7 October 1997 © 1998 Wiley-Liss, Inc. lems in the ultrasound and pathologic diagnosis of WWS in the fetal period. Am. J. Med. Genet. 76:107–110, 1998. © 1998 Wiley-Liss, Inc. KEY WORDS: hydrocephalus; lissencephaly; retinal dysplasia; kidney dysplasia; muscle dystrophy; atretic cephalocele INTRODUCTION Walker-Warburg syndrome (WWS) is a lethal autosomal recessive disorder manifested by characteristic brain and eye malformations and congenital muscle dystrophy [Dobyns et al., 1989; Dubowitz and Fardeau, 1995]. Three prenatally diagnosed cases of WalkerWarburg syndrome that occurred in a consanguineous family are reported with special regards to practical problems in the ultrasound and pathologic diagnosis of WWS in the fetal period. CLINICAL REPORTS Family history dates back to 3 years ago when the first pregnancy occurred to a 18-year-old woman and her 19-year-old husband. They were first cousins, of Turkish extraction. This pregnancy was uncomplicated until the 27th week when hydrocephalus was detected ultrasonographically (biparietal diameter [BIP]: 71 mm; head circumference [HC]: 25 cm, marked ventricular enlargement, ventricular size, and cortical mantle thickness not available). Amniocentesis demonstrated a normal 46,XY karyotype. A termination of pregnancy was performed upon request but autopsy was declined by the parents. Seven months later, ultrasound monitoring of the second pregnancy led to the diagnosis of recurrent hydrocephalus at the 20th week. At 16 weeks, BIP and HC were, respectively, 33 mm and 13.1 cm; at 20 weeks, BIP was 55 mm and HC was 19.3 cm; lateral ventricle size was 14 mm, the third ventricle size was 13 mm, cortical mantle thickness ranged from 5 to 8 mm. Abortion was subsequently induced at the 22nd week. A 108 Gasser et al. normal male karyotype was documented. Autopsy showed a male fetus whose weight and height (500 g, crown rump length [CRL]: 18 cm) were consistent with the gestational age. With the exception of the head and brain, the findings were normal; no thumb malposition was found. The fetus had mild hypertelorism, flat bridge of nose and anteverted nostrils, long philtrum in contrast with a small chin, mildly low-set posteriorly angulated ears, and flat occiput. The head circumference was slightly enlarged. Atretic occipital cephalocele, hydrocephalus, and major cerebral and retinal dysplasia were present leading to the diagnostic hypothesis of Walker-Warburg syndrome in spite of the apparent absence of muscle changes. In the third pregnancy, 10 months later, ultrasonographic monitoring demonstrated during the 13th week a bilateral dilatation of lateral ventricles (BIP: 26 mm; ventricular size: 7 mm). At 15 weeks, BIP and ventricular sizes were, respectively, 30 mm and 9 mm. Ventricular size reached 13 mm at 17 weeks. As of the 13th week, cystic changes in the right kidney were found and confirmed by ultrasound follow-up: right kidney enlargement (renal circumference: 50 mm at 15 weeks) with cysts of varying size and renal pelvis distention (8 mm at 15 weeks, 14 mm at 17 weeks). The left kidney was normal. Neither ocular anomaly nor skull defect could be demonstrated. The diagnosis of Walker-Warburg syndrome was considered again. Despite the normality of the left kidney, a diagnosis of a variant of Meckel syndrome was debated, taking into account the presence in the preceding sib of an equivalent of meningocele and the present occurrence of kidney cystic changes. Termination of pregnancy was performed during the 20th week, and this third female sib (weight: 348 g; CRL: 16 cm) showed head and brain defects similar to those found in the previous case, i.e., occipital bone defect, hydrocephalus, and major cerebral and retinal dysplasia. PATHOLOGIC FINDINGS Shortly after termination, placenta and fetus were fixed for a week in 10% aqueous solution of phosphatebuffered formalin. The brain was fixed for another 10 days after removal. Following gross examination, paraffin sections were stained with hematoxylin and eosin. Both the second and the third sib demonstrated similar skull, brain, and eye anomalies. A 3-mm bone defect was present in the upper part of the occipital bone without demonstrable meningocele or encephalocele (Fig. 1). In both sibs, there was marked enlargement of the lateral ventricles (Fig. 2) with irregular thinning of surrounding brain tissue and leptomeningeal irregularities running alongside the whole brain surface. Adhesion without cortical joining could be seen between the frontal lobes. The corpus callosum was present. The cortical surface appeared totally smooth except for the Sylvian fissure which appeared abnormally flat for the age. However, it should be noted that smoothness of the external brain surface is a normal finding until about the 22nd–23rd gestational week. By contrast, both parieto-occipital and calcarine sulci are, in our experience, normally recognizable as of the 16th week. Fig. 1. Three-mm bone defect in the upper part of the occipital bone without demonstrable meningocele or encephalocele. In both cases, the internal surface of both parietal and occipital lobes was abnormally smooth. Considering the fetal age, the cerebellum was considered normal. Histologically, the cortical structure was in disarray in all regions. Different patterns of changes could be seen according to the cortical topography. The cortical mantle in the upper and lateral part of the parietal convexity and in the floor of lateral ventricles was divided into two approximately equal parts by a vascular band underlined by clusters or laminae of neurons with only scarce and focal areas of radial alignment. The outer part was made of neuronal and glial cells arranged in irregular nests or bands dissociated by bundles of white matter. The disorganized neurons and glial cells often extended into the subarachnoid space (Fig. 3). In the external wall of ventricles, only scarce neurons remained beneath the above described vascular band. Neurons seemed to have migrated to the outer part of mantle where they appeared interspersed Fig. 2. Marked dilatation of lateral ventricles with irregular thinning of the surrounding brain tissue with interhemispheric adhesion without cortical joining and smooth cortical surface. Walker-Warburg Syndrome 109 cystic right kidney (Fig. 5) containing 5 cysts of 4 to 8 mm diameters, and several cortical microcysts. The main cysts responded to largely dilated calices associated with pelviureteric junction fibrous stenosis. Hydronephrosis and tubular or glomerular subcapsular cysts in an otherwise conserved renal architecture were found in the surrounding kidney. Only mild cortical changes related to the urinary obstruction could be observed. The left kidney was normal. No ductal plate malformation could be found in the liver. DISCUSSION Fig. 3. Total disturbance of the brain structure in the outer part of cortex: neuronal and glial cells arranged in irregular nests or bands dissociated by bundles of highly vascularized connective tissue (a). Neurons and glial cells extending into the subarachnoid space (b) H.E.: ×200. with connective tissue and capillaries and formed disorganized neuronal and glial waves beneath and in the subarachnoid space. Similar cell disorganization could be found at the mesencephalic level but the aqueduct of Sylvius was normal. No growth anomaly of the ocular globes was found. Lenses were normal but retinal dysplasia was clearly demonstrated, characterized by gliovascular proliferation in the inner retinal layers and rosettes (Fig. 4). Histologic structure of the ilio-psoas and ocular muscles was normal as compared with age-matched controls. Few myotubes were scattered among myofibers whose cytoplasm was normal. Neither myofiber size variation nor increase in the amount of endomysial or perimysial connective tissue could be demonstrated. In the third sib, abdominal dissection showed a huge Fig. 4. Retinal dysplasia: gliovascular proliferation in the inner retinal layers and rosettes. H.E.: ×200. The diagnostic criteria for WWS are clearly delineated: cobblestone lissencephaly with variable gyral malformation, diffuse white matter abnormality, retinal abnormality, and congenital muscular dystrophy by 1 year [Dubowitz and Fardeau, 1995]. The structural cerebral changes observed in both the second and the third sib were similar to those previously described in fetal cases of WWS [Miller et al., 1991; Squier, 1993]. The association of cortical dysplasia, retinal dysplasia, and atretic encephalocele led us to the diagnostic hypothesis of WWS in spite of the lack of muscle dystrophic changes. This diagnosis was further supported by the family history. These cases illustrate the diagnostic problems in Fig. 5. Cystic changes in the right kidney related to pelviuretic junction stenosis. 110 Gasser et al. ultrasonographic and histopathologic assessment of WWS in the fetal period. Hydrocephalus was present in all three of our cases, and ventriculomegaly with or without macrocephaly was present in 40/41 cases of WWS reviewed by Dobyns et al. . Thus, the detection of hydrocephalus in a fetus at risk for WWS should be considered presumptive evidence in support of the diagnosis. By contrast, while many other malformations in major systems of the body can be detected prenatally by fetal ultrasonography, lissencephaly cannot be diagnosed with confidence by this method. No ocular malformation could be detected ultrasonographically in our cases. If ocular anomalies are rather characteristic for WWS, ultrasound examination seems to be most often not relevant to such a diagnosis [Miller et al., 1991; Denis et al., 1993; Rodgers et al., 1994] during the second trimester. The prenatal diagnosis of retinal detachment has been reported only after 32 weeks [Farrell et al., 1987; Vohra et al., 1993; Chitayat et al., 1995]. Thus, the presence of eye malformation may provide additional supportive evidence for prenatal diagnosis of WWS but its absence does not exclude it. Therefore, postmortem studies are necessary to obtain histopathologic evidence of diagnosis. The occurrence of such rather uncommon findings as renal anomalies in the third sib, and the lack of muscle changes in both the second and the third sib, illustrated difficulties in establishing the diagnosis of WWS in a fetus not known to be at risk for this disorder. The association skull defect—right dysplastic kidney in the third sib led us to consider the possibility of Meckel syndrome (MS). Some findings argued this hypothesis. The polycystic renal changes in MS are bilateral, in contrast with the unilateral lesions seen in this fetus. Moreover, the histologic lesions were not consistent with MS: these responded to a huge renal pelvis distention with hydronephrosis, conserved renal architecture, and presence of tubular and glomerular subcapsular cysts [type IV dysplasia in OsathanondhPotter classification . Such lesions are not consistent with MS but have been described in fetal obstructive uropathies [Gasser et al., 1993]. Moreover, the congenital hepatic fibrosis characteristic of MS could not be demonstrated. The relation between renoureteral anomalies and WWS is unclear. In those studies where urograms were performed [Whitley et al., 1993], these were normal. To our knowledge, only one fetal case of WWS with bilateral hydronephrosis has been reported in a 38-week fetus by Denis et al. . The expected muscle changes included endomysial and perimysial fibrosis, increase in the variability of fiber sizes, varying degrees of myofiber necrosis, and inflammatory infiltrate [Lichtig et al., 1993]. By contrast, muscle normality in our cases was critical to the diagnosis of WWS. The absence of muscular abnormality in WWS has been mentioned, especially before birth and in the first year of life [Dobins et al., 1989; Dubowitz, 1996]. None of the reported fetal observations of WWS (age range from 18 to 32 weeks) showed dystrophic changes [Miller et al., 1991; Denis et al., 1993; Squier, 1993; Voit in Dubovitz, 1996; Bornemann et al., 1996]. It must be emphasized that the lack of muscle changes cannot exclude the diagnosis of WWS: the variability in the age of onset and severity of muscle dystrophy has already been underlined [Dobyns et al., 1989; Dubowitz and Fardeau, 1995]. Whereas Miller et al.  noted histologic muscle changes in a 1-dayold infant with WWS, most histopathologic active degenerative changes in muscles have not been reported sooner than the third month of life [Miyake et al., 1977; Lichtig et al., 1993]. This suggests that overt muscular dystrophy occurs during a late fetal period and even in the postnatal period as has been described in Fukuyama syndrome [Takada et al., 1987] and in Duchenne muscular dystrophy. These data seem of interest with respect to the prenatal histopathologic diagnosis of WWS, which is probably compatible with the lack of muscular changes. 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