Blackwell Publishing AsiaMelbourne, AustraliaCGACongenital Anomalies0914-3505The Japanese Teratology Society, 2006? 2006463160162Case ReportCallosal agenesis followed postnatally after prenatal diagnosisG. Imataka et al.

160

Congenital Anomalies 2006; 46, 160–162

doi:10.1111/j.1741-4520.2006.00120.x

CASE REPORT

Callosal agenesis followed postnatally after prenatal diagnosis
George Imataka1, Eiji Nakagawa1,2, Shigeko Kuwashima3, Hiroshi Watanabe4, Hideo Yamanouchi1, and Osamu Arisaka1
Departments of 1Pediatrics, 3Radiology and 4Obstetrics and Gynecology, Dokkyo Medical University School of Medicine, Mibu, Tochigi
and 2Division of Child Neurology, National Center of Neurology and Psychiatry, Musashi Hospital, Kodaira, Tokyo, Japan

ABSTRACT Callosal agenesis is a congenital brain
anomaly caused by embryonal hypogenesis of the corpus callosum. Concerning the neurological prognosis, epilepsy andmotor disturbance are noted in some cases, while many cases
are asymptomatic and the prognosis is good. We report a fetus
tentatively diagnosed with hydrocephaly on prenatal echoencephalography, which was performed without adequate
explanation to and understanding of the parents. The parents
had not expected an abnormality before the screening, and were
subsequently not psychologically prepared for the discovery of
the congenital brain anomaly on imaging. Moreover, theyreceived no guidance on how to deal with any possible abnormalities. The pregnant mother was referred to our hospital. Prenatal MRI was performed after informed consent was obtained,
and the fetus was diagnosed with callosal agenesis. The patient
was followed for 5 years, and neurological development wasnormal. However, the parents have remained anxious whileraising the child. Thus, the prenatal diagnosis of callosal agenesis in this case caused unnecessary mental burden to the parents. Here, we report the course of the case, and discuss the way
prenatal ultrasonography should be used as a prenatal screening method, and the importance of counseling before the test.
Key Words: callosal agenesis, fetal magnetic resonance imaging,
genetic counseling, prenatal echogram, screening

INTRODUCTION
Accuracy in the diagnosis of callosal agenesis and hydrocephaly
remains unclear. Many cases are asymptomatic, and diagnosis may
not be made without radiological imaging in many cases. The
disorder is incidentally detected on radiography of the brain performed for other purposes, suggesting that it is not rare. Thus, it
should be kept in mind that prenatal ultrasonic screening may detectcallosal agenesis and hydrocephaly even though the fetal development is normal. We encountered a case prenatally diagnosed withcallosal agenesis by fetal MRI performed upon discovery of anabnormality on ultrasonography. Prenatal ultrasonic screening had
been performed with inadequate informed consent. The parents hadreceived a serious psychological impact from the echogram result,which had a negative impact on raising the child even though her
neurological development was normal. Here, we report the clinicalcourse of the case, and discuss prenatal echographic screening.

Correspondence: George Imataka, MD, Department of Pediatrics, Dokkyo
Medical University School of Medicine, 880 Kitakobayashi, Mibu, Shimotsuga, Tochigi 321-0293, Japan. Email: geo@dokkyomed.ac.jp
Received October 24, 2005; revised and accepted May 10, 2006.

© 2006 The Authors
Journal compilation © 2006 Japanese Teratology Society

CLINICAL REPORTThe patient was the mother of a 5-year-old girl who has been undercounseling from before the delivery of the child because of anxiety
concerning the development and raising of her child with a congenital brain anomaly. There was no problematic past or familial
medical history. The mother had undergone ultrasonic screening at
31 weeks of gestation, and fetal hydrocephaly was tentatively diagnosed. Fetal development was normal and consistent with the gestational age on ultrasonography before 31 weeks, and the mother
had not expected this abnormality. The mother was shown theechogram during the examination, and was shocked by the findingof congenital brain anomaly. She was subsequently referred to ourhospital, and underwent ultrasonography. The lateral ventricle ofthe fetus was enlarged in a teardrop shape, and the corpus callosum
could not be confirmed. After obtaining informed consent from theparents, prenatal MRI was performed at 34 weeks of gestation.
Colpocephaly was noted in the fetal skull, the callosum was notimaged in the cerebrum, the bilateral ventricles were parallel, andthe posterior horn was enlarged. Since the medial cerebral sulci
radiated toward the 3rd ventricle in the sagittal view, callosal agenesis was diagnosed (Fig. 1A,B).
The child was born by natural delivery at 38 weeks of gestation
with a birth weight of 2480 g, and the 1- and 5-minute Apgar Scores
were 8 and 9, respectively. No anomaly was found on physicalexamination. Feeding was normal, and there was no problem in thedevelopment. However, the parents were very anxious about theirchild with a congenital abnormality of the brain. Thus, we periodically counseled the parents, and explained that the prognosis ofcallosal agenesis varies, and many cases are asymptomatic,
although epilepsy and motor disturbance occur in some cases. The
mother and infant were discharged three weeks after birth. At
3.5 months after birth, spindles were noted in electroencephalogram of the bilateral central regions, but no epileptic spikes weredetected. The motor development of the infant was normal andconsistent with the age: the neck stabilized at 3.5 months of age,tossing and turning appeared at 5.5 months, being able to maintaina sitting position at 8 months, and walking at one year and 1 monthof age. Speech of single words appeared at one year of age. On
MRI at two years and 2 months of age, callosal defect was noted,
but myelination corresponded to the age (Fig. 1C,D). The child isnow five years old; psychomotor and speech developments arenormal. But the mother is still anxious about the child’s future. We
follow under periodic counseling with examination of the child.

DISCUSSION
The corpus callosum appears at approximately 10 weeks of gestation, and the development is almost complete at 17 weeks. Callosal
agenesis occurs during this period (Kendall 1983). Thus, althoughCallosal agenesis followed postnatally after prenatal diagnosis

Fig. 1161

Fetal magnetic resonance imaging (HASTE: half-Fourier acquisition single-shot trubo spin echo method: effective TE = 64.0/1 ms, TR = 4.4 ms,
TA = 00:15, matrix 128 × 256, FOV 300–400 mm) showed agenesis of the corpus callosum (A) and colpocephaly (B). Magnetic resonance imaging.
Sagittal T1 (right: spin echo: TE = 15, TR = 400 ms) and axial T2 (left: spin echo: TR = 3800 TE = 110) weighted-images. Myelination wasconsistent with her age (C, D).

ultrasonography is normal before 10 weeks, callosal agenesis may
be diagnosed thereafter. Drugs, infection, cerebrovascular disorder,and trauma have been speculated to be the causes of callosal agenesis. Its prevention is not possible, and no therapy is available. Early
diagnosis of callosal agenesis is important for the investigation ofcomplications. A defect of the callosum alone may be noted, but it
may also be complicated by congenital hydrocephaly, Dandy–Wakwer syndrome, Chari deformity, myelomeningocele, total frontal cerebral vesicle, agyria, encephalodysplasia, Aicardi syndrome(Jellinger et al. 1981). The degrees of symptoms and developmental
disorders vary depending on the type of complicating anomalies
and other cerebral disorders which may be present. Clinically, there
is no callosal defect-specific symptom. Convulsive attacks, motor
paralysis, and psychomotor developmental retardation may occur
from the neonatal period, or diagnosis can be made based on epilepsy and various neurological abnormalities, whereas some cases
present no clinical symptoms throughout their life, and the defectis incidentally diagnosed after adolescence in others. In this patient,motor and mental development was normal. However, the parents
are still very anxious about raising their child, and under periodic
counseling. If the prenatal ultrasonography had not been performed,
the parents would not have such anxieties about raising their child.
The early diagnosis resulted in a long-term negative effect on raising their child associated with their anxiety in this case.

Advances in prenatal MRI and ultrasonography have allowed
early prenatal diagnosis of various disorders, which is of great
medical benefit, enabling us to initiate fetal treatment from an earlystage (Gupita & Liford 1995; Sonigo et al. 1998). However, parents
under perinatal management may see an abnormal image of thefetus and become anxious. Prenatal imaging diagnosis is very problematic in that it may provide non-beneficial medical informationand cause anxiety, and it may detect hereditary diseases. However,in actual practice, ultrasonography is performed as a screening tool
to examine the gestation sac and fetal heart beats to confirm pregnancy in the early phase without adequate explanation of various
disorders that may be incidentally discovered. The possibility ofsuch findings should be explained before prenatal imaging, such as
ultrasonography and fetal MRI, is performed, and the family should
be counseled concerning possible unexpected findings including
obtaining informed consent on whether or not the findings are tobe disclosed.

ACKNOWLEDGMENTS
This work was supported by the Dokkyo Medical University,
Investigator-Initiated Research Grant (No. 2005-01-5) and the Ministry of Education, Culture, Sports, Science and Technology (MEXT)
KAKENHI 18790733 Grant-in-Aid for Young Scientists (B).
© 2006 The Authors
Journal compilation © 2006 Japanese Teratology Society

162

G. Imataka et al.

REFERENCES
Gupita JK, Liford RJ (1995) Assessment and manadement of fetal agenesisof the corpus callosum. Prenat Diag 15: 301–312.
Jellinger K, Gross H, Kaltenback E, Grisold W (1981) Holoprosencephaly
and agenesis of the corpus callosum: Frequency of associated malformations. Acta Neuropathol (Berl) 55: 1–10.

© 2006 The Authors
Journal compilation © 2006 Japanese Teratology SocietyKendall BE (1983) Dysgenesis of the corpus callosum. Neuroradiology 25:239–256.
Sonigo PC, Rypens FF, Carteret M, Delezoide AL, Brunelle FO (1998) MR
imaging of fetal cerebral anomalies. Pediatr Radiol 28: 212–222.