Prenatal diagnosis of retinal nonattachment in the Walker-Warburg syndrome

Prenatal diagnosis of familial exudative vitreoretinopathy and Norrie disease

Background

Both familial exudative vitreoretinopathy (FEVR) and Norrie disease (ND) are hereditary retinal disorders which can cause severe visual impairment and blindness at a young age. The present study aimed to report the use of antenatal genetic testing and ultrasound in the diagnosis and counseling of FEVR and ND.

Methods

Amniocentesis and ultrasonography were performed in high‐risk mothers, with children having FEVR or ND, to predict severe ocular abnormalities.

Results

Case 1: A homozygous NDP mutation (c.376T>C, NM_000266) was detected in the proband and his mother. Molecular prenatal analysis of the fetal DNA revealed no mutations. No ocular abnormalities were detected on ultrasonography. The pregnancy progressed uneventfully to a normal outcome. Case 2: A novel heterozygous FZD4 mutation (c.1010dupA, NM_012193) was detected in the proband and his mother. The same mutation was detected in the fetus, but ultrasonography showed no ocular abnormalities. A healthy baby boy with stage 1 FEVR was born after an uneventful pregnancy. Case 3: Deletions of exons 2 and 3 in the NDP were found in the proband and his mother. The same deletion mutation was detected in the female fetus, but the ultrasound scan was normal. The pregnancy progressed uneventfully to a normal outcome.

Conclusions

To our knowledge, antenatal genetic analyses were used in conjunction with ultrasound for the first time, to diagnose FEVR and ND, and predict the postnatal prognoses in at‐risk babies.

Bilateral total retinal detachment at birth: a case report of Walker-Warburg syndrome

Walker–Warburg syndrome (WWS) is a disorder characterized by ocular and brain malformations, and congenital muscular dystrophy. Retinal malformations are common in WWS; however, bilateral retinal detachment is a rare occurrence. We present a case of a newborn baby delivered at 36+3 weeks, who was the first living child of consanguineous parents of Turkish origin. On antenatal anomaly scans, the fetus had hydrocephalus that had increased throughout pregnancy, and a diagnosis of hydrancephaly was made at 36 weeks of gestation. Hypotonia, cleft lip and palate, poor suck and absent gag reflex were noted at birth. Ophthalmic examination at the age of 2 days revealed bilateral funnel retinal detachment. B-scan ultrasonography confirmed these findings, and magnetic resonance imaging (MRI) of the brain was performed at the age of 13 days to establish a diagnosis. The MRI showed lissencephaly, hydrocephalus and thin rim of brain parenchyma, with a cobblestone appearance of the cortex and pontine and cerebellar hypoplasia, consistent with the diagnosis of WWS. The infant deteriorated and died at 39 days of age from complications associated with the brain anomalies. In summary, bilateral retinal detachment is extremely rare and in association with hydrocephalus and posterior fossa anomalies strongly suggests the diagnosis of WWS.

Very Early In-Utero Diagnosis of Walker-Warburg Phenotype: The Cutting Edge of Technology

BACKGROUND

Walker-Warburg phenotype is a severe and lethal autosomal recessive disorder, belonging to a group of congenital malformations defined as abnormal pial basement membrane formation. So far, prenatal diagnosis was considered possible only during late pregnancy.

METHODS

First trimester assessment of a pregnancy suspected to be affected by Walker-Warburg phenotype, using a high-resolution transvaginal ultrasound probe (6-12 MHz), T2 MR imaging (1.5T), molecular genetics and histopathology.

RESULTS

Very early diagnosis of the Walker-Warburg phenotype at 11 weeks of gestation proved possible by depicting the classic signs of this entity, confirmed by molecular genetics, post-abortion MR imaging and histopathology.

CONCLUSION

Advancements in ultrasound equipment and technology, molecular genetics and histopathology have made very early detection of this syndrome possible, thus shedding new light on the natural history of this malformation.

Prenatal Diagnosis of Persistent Hyperplastic Primary Vitreous: Report of 2 Cases and Review of the Literature

Persistent hyperplastic primary vitreous is a spectrum of congenital ocular abnormalities characterized by leukocoria, microphthalmia, cataracts, extensive intravitreal hemorrhage, persistence of the hyaloid artery, glaucoma, and retinal detachment. It might be isolated or associated with congenital syndromes such as trisomy 13, Walker-Warburg syndrome, and Norrie disease. We present 2 cases of persistent hyperplastic primary vitreous diagnosed by prenatal sonography in the early third trimester. Bilateral hyperechoic lenses and retinal nonattachment were detected in the sonographic examination of the first case, whereas irregular echogenic bands between the lenses and posterior walls of the eyes were prominent in the second case. In both of the cases, ocular findings were accompanied by intracranial findings, including severe hydrocephalus, an abnormal gyral pattern, and cerebellar hypoplasia, suggesting the diagnosis of Walker-Warburg syndrome. We also present a review of the literature regarding the prenatal diagnosis of this malformation.

Abnormalities of the foetal cerebral cortex

Prenatal ultrasound has concentrated on readily visible cerebral structures including head size, shape, ventricles, CSP (cavum septi pellucidi), cerebellar size/vermian presence and cisterna magna. However, apart from these easily visible structures it is important to evaluate the brain itself. Patients who initially appear to have mild isolated findings such as borderline ventriculomegaly in fact can have many more subtle findings that significantly alter prognosis and management that can be detected on detailed examination of the brain. There has been rapid evolution in imaging these foetuses, especially with neurosonography and MRI, and a revolution in understanding the underlying genetic and biochemical mechanisms. There is increasing emphasis to detect cortical abnormalities as early as possible. This article reviews development of the cerebral cortex, the classification, aetiologies and clinical manifestations of cortical disorders, normal and abnormal appearances at ultrasound and MRI, and approaches to investigation.

Difficulties with prenatal diagnosis of the Walker-Warburg syndrome

We describe a postnatally diagnosed case of Walker-Warburg syndrome--a form of congenital muscular dystrophy with lissencephaly and eye abnormalities. We reviewed the literature to highlight its clinico-radiological diagnostic features and discuss the difficulties encountered with prenatal diagnosis, especially in cases with no positive family history. An increased awareness of this rare but lethal condition, and a high index of suspicion during routine antenatal ultrasound, could prompt further advanced fetal ultrasonography and magnetic resonance imaging, and aid in timely prenatal diagnosis, management, and counseling.

First-trimester ultrasound diagnosis in a recurrent case of Walker-Warburg syndrome

We report on two siblings with Walker-Warburg syndrome (WWS) born to a consanguineous couple. In the index case, the second-trimester scan showed ventricular dilatation and we diagnosed WWS after observing retinal detachment at 26 weeks' gestation and lissencephaly by 32 weeks' gestation in addition to hypoplasia of the cerebellar vermis. The second case was first suspected at 12 weeks' gestation, when we observed a 2.8-mm nuchal translucency and an unusually large hindbrain vesicle. By 14 weeks' gestation, the lateral ventricles were clearly enlarged (12-13 mm), at 16 weeks' gestation the vitreous chamber appeared to be hyperechogenic, and by 17 weeks' gestation hydrocephalus was evident. The couple chose to continue the pregnancy, and during the third trimester lissencephaly, major hydrocephalus and polyhydramnios developed. Serial ultrasound examination should be offered to a family with a history of WWS and therefore a 1 in 4 risk of recurrence. In some cases, recurrence can be suspected as early as the first trimester, however the diagnosis cannot be excluded on the basis of normal ultrasound appearance until later in pregnancy.

Anaesthesia for a child with Walker-Warburg syndrome

Walker-Warburg syndrome (WWS) is a rare lethal autosomal recessive disorder manifested by characteristic central nervous system and eye malformations. We have not come across reports of general anaesthesia in a child with WWS in the English literature. We report a case of general anaesthesia in a 12-month-old male child with WWS. The child also had bilateral cleft lip, cleft palate, urogenital malformation and hydronephrosis. Despite many potential anaesthesia concerns, anaesthesia was uneventful in this child.

Ocular findings in lissencephaly

PURPOSE

To report our retrospective study of 20 cases with lissencephaly and describe ocular and visual abnormalities associated with this disorder.

METHODS

Patients with lissencephaly were identified and classified into classic (type I) or cobblestone (type 2) lissencephaly on the basis of a review of clinical records and neuroimaging studies. Only patients examined by an ophthalmologist were included in the study.

RESULTS

Only 1 patient had a normal ocular examination. Ocular abnormalities included optic nerve hypoplasia and atrophy, retinal dysplasia, retinal nonattachment, macular hypoplasia, anterior segment malformation, and strabismus.

CONCLUSIONS

Ocular abnormalities in classic (type 1) lissencephaly are less severe. Central, steady, and maintained fixation may be present despite the presence of optic nerve hypoplasia, optic atrophy, macular hypoplasia, strabismus, or refractive errors. Retinal and anterior segment abnormalities were observed only in cobblestone (type 2) lissencephaly. These patients often have severe visual impairment because of retinal or cortical disease.

Basal lamina abnormality in the skeletal muscle of Walker-Warburg syndrome

The basal lamina of skeletal muscle fibers has been reported to be thinned and disrupted in patients with Fukuyama and laminin-alpha-2-deficient congenital muscular dystrophies. The basal lamina is normal in other, later-onset, muscular dystrophies, but the plasma membrane is disrupted. It is unknown whether the dystrophic process in Walker-Warburg syndrome (WWS) is characterized by a basal laminal abnormality, a sarcolemmal abnormality, or both. The present study examined the skeletal muscle of a 3-month-old patient with WWS by immunohistochemistry and electron microscopy and compared the findings with control muscle samples. In control samples the basal lamina of skeletal muscle fibers was a continuous, uniformly dense structure associated with sarcolemma. In WWS the basal lamina appeared deranged, with disruptions in nonnecrotic muscle fibers. Furthermore, in some fibers the basal lamina was thinner, and in others, it was duplicated. Dystrophin, laminin-alpha-2, and adhalin stains revealed normal immunoreactivity. The disruptions in the basal lamina may play a primary role in the degeneration of muscle fibers in WWS. When compared with the dystrophies with a primary sarcolemmal defect, it appears that those with primary basal lamina abnormalities (WWS, laminin-alpha-2-deficient, and Fukuyama congenital muscular dystrophies) present early in life, and the phenotype is more severe.

Gonadoblastoid testicular dysplasia in Walker-Warburg syndrome

Two male fetuses (18 and 22 weeks gestation) and a 3-month-old male infant (full sibling of the younger fetus) who were diagnosed with Walker-Warburg syndrome (WWS) on the basis of neuropathologic autopsy findings in brain, eyes, and muscle also had micro-orchia and, microscopically, diffuse gonadoblastoid dysplasia in the testes. Both fetuses also had a miniature left ureter and cystic dysplastic left kidney. Testes from control fetuses of 17-24 weeks gestation with normal karyotype and no central nervous system abnormalities (group A, n = 50), a variety of central nervous system abnormalities (group B, n = 50), or an autosomal aneuploidy syndrome with or without central nervous system abnormalities (group C, n = 30) had no diffuse dysplasia, although a single gonadoblastoid seminiferous tubular profile was present in three controls. Testicular morphology was normal in older fetuses and infants with a wide variety of central nervous system malformations (group D, n = 50). We found no evidence of hypogonadotrophic hypogonadism in the three WWS cases to account for the small penis and incompletely descended testes commonly reported in this condition. We concluded that the apparent specificity of the gonadoblastoid testicular dysplasia to WWS suggests that the gene defect directly affects testicular development.

Omphalocele in Miller-Dieker syndrome: expanding the phenotype

We report on a patient prenatally diagnosed with omphalocele, mild cerebral ventriculomegaly, nuchal fold thickening, and cystic changes in the umbilical cord who was found postnatally to have lissencephaly type I. Prenatal chromosome analysis showed a normal male karyotype; however, postnatal high resolution banding and FISH analysis, using a probe for locus D17S379 in chromosome region 17p13.3, demonstrated a deletion at 17p13.3 consistent with Miller-Dieker syndrome (MDS). A review documented four more cases with MDS/isolated lissencephaly/17p-, with omphalocele. Because MDS is a contiguous gene disorder, we speculate that a gene or genes in this region have a major role in the closure of the lateral folds or the return of the midgut from the body stalk to the abdomen at 5-11 weeks of gestation. Prenatal diagnosis of omphalocele with mild ventriculomegaly should prompt FISH analysis for a deletion in 17p13.3.