Antenatal Sonographic Diagnosis of A Case of Alobar Holoprosencephaly: A Case Report

doi:10.4236/ijcm.2012.35080

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International Journal of Clinical Medicine, 2012, 3, 431-432

http://dx.doi.org/10.4236/ijcm.2012.35080 Published Online September 2012 (http://www.SciRP.org/journal/ijcm) 1

Antenatal Son ographic Diagnosis of a Case of Alobar

Holoprosencephaly: A Case Report

Rizwan Ahmad Khan1, Manjari Thapa2, Shagufta Wahab2*

1Division of Pediatric Sugery, Department of Surgery, JN Medical College, Aligarh Muslim University, Aligarh, India; 2Department

of Radiodiagnosis, JN Medical College, Aligarh Muslim University, Aligarh, India.

Email: *[email protected]

Received May 2nd, 2012; revised June 6th, 2012; accepted July 19th, 2012

ABSTRACT

Holoprosencephaly is a rare congenital brain malformation resulting from failure of diverticulation and cleavage of

primitive prosencephalon which occurs at 4th - 8th week of gestation and is usually associated with multiple midline

facial anomalies. Herein we report an antenatal case of such patient. Patient was evaluated and because of the magni-

tude of the problem induction was done which led to a still born baby.

Keywords: Holoprosencephaly; Alob ar; Antenatal Detection; Developing Countries; Prognosis

1. Introduction

Holoprosencephaly is a rare congenital brain malforma-

tion resulting fro m failure of diverticulation and cleavage

of primitive prosencephalon which occurs at 4th - 8th

week of gestation and is usually associated with multiple

midline facial anomalies. This disorder is either incom-

patible with life or infants suffer from varying grade of

mental retardation.

Sonography is an excellent non-invasive tool for pre-

natal diagnosis of holoprosencephaly. This case report

describes a case of alobar holoprosencephaly diagnosed

prenatally with ultrasound and highlights the importance

of high-resolution real time imaging. We want to stress

that the conditio n is rare and therefore lack of familiarity

may lead to diagnostic confusion.

2. Case Report

A 24-year-old, gravida 2 and para 1 underwent antenatal

ultrasonography at 24 menstrual weeks as determined by

dates, which disclosed increased intracranial fluid in the

fetus. Past medical history and family history were un-

remarkable, with the previous child being born at term

with no congenital anomaly. A repeat ultrasound exami-

nation demonstrated a monoventricle fluid-filled cavity.

The cerebral cortex was represented by thinned out man-

tle. Two orbits were seen; no clear evidence of proboscis

was seen. The midbrain and posterior fossa appeared

normal (Figures 1). An increased amount of amniotic

fluid (polyhydramnios) was present. Based on the ante-

natal sonographic findings a diagnosis of alobar holo-

prosencephaly was made. Preterm induction of vaginal

delivery resulted in a stillborn fetus. Examination of the

fetus demonstrated only proptosis but no gross facial

anomaly. Brain morphology could not be assessed due to

autolysis. Chromosomal analysis disclosed a trisomy 13

karyotype. Patient was investigated as per the guidelines

set by the Ethics committee of our hospital.

3. Discussion

The incidence of holoprosencephaly is approximately 1 -

1.4 per 10,000 live births [1] but as the incidence of

Figure 1. Antenatal sonogram of fetal head (coronal view)

with alobar holoprosencephaly showing monoventricular

cavity with surrounding thinned cerebral tissue, fused tha-

lami and absence of midline structures such as falx cerebri.

Axial view of the same patient showing fused thalami and

thinned out cortical mantle of the fetal head.

*Corresponding a uthor.

Antenatal Sonographic Diagnosis of a Case of Alobar Holoprosencephaly: A Case Report

432

spontaneous abortions is high, the actual incidence may

be quite high. Both environmental factors and genetics

are suspected in its etiology and approximately 30% of

the cases are associated with chromosomal defects

mostly trisomy 13 and 18. However most of the cases

have a normal karyotype [2]. It represents a spectrum of

disorder with most severe form known as alobar type

showing absolutely no cleavage of prosencephalon with a

large monoventricular system surrounded by a thinned

out mantel with absent falx cerebri, corpus callosum,

fornix, optic tract and olfactory bulbs. The thalami are

fused with absent third ventricle and the single ventricle

usually communicates with a dorsal sac [3]. The infants

are stillborn or survive only upto few d ays or weeks. Se-

milobar holoprosencephaly is an intermediate form with

posterior partial separation of two hemispheres and ven-

tricles thus a rudimentary occipital horn with a small

portion of falx and interhemispheric fissure in the oc-

cipital cortex may be seen. Thalami are partially sepa-

rated with a rudimentary third ventricle [3]. The least

severe form is the lobar variety showing almost complete

separation of cerebral hemispheres and lateral ventricle

with developed falx and interhemispheric fissure so pre-

natal diagnosis may be difficult. Cavum septum pellu-

cidum is however absent and there is fusion of frontal

horns [3]. This syndrome is associated with mild mental

retardation. The mildest form is septo-optic dysplasia

with absent septum pellucidum, optic nerve hypoplasia

and associated hypothalamic-pituitary dysfunction. As

the face develops at the same time as the diverticulation

of brain, holoprosencephaly is accompanied by a number

of midline facial anomalies and the degree of facial dys-

morphism parallels the severity of holoprosencephaly so

sonographic evaluatio n of facial morphology may he lp in

prenatal diagnosis of holoprosencephaly. Studying the

strong association between facial anomalies and holo-

prosencephaly, DeMeyer commented “brain malforma-

tions can be predicted by patient’s face” [4]. The severest

facial malformation like cyclopia, ethmocephaly and ce-

bocephaly occurred only with alobar holoprosencephaly

[5] with semilobar and lobar types showing milder facial

anomalies .These are hypotelorism, median cleft lip and

palate, lateral cleft lip and palate and pyriform aperture

stenosis [5-7]. However the face may even be almost

normal in few cases of alobar holoprosencephaly as in

our case. Other extrafacial anomalies are also common

with holoprosencephaly and includes polydactyly, renal

dysplasia, omphalocele, club foot, esophageal atresia,

cardiac malformation etc. [4,5]. Routine obstetric USG is

performed during the first trimester preferably between

11th - 14th week of gestation and besides determining

the gestational age, number of foetuses and presence of

any complication, USG can also detect a number of con-

genital ano malies. Sonography is most helpful in th e pre-

natal diagnosis of holoprosencephaly especially of alobar

type and is the decisive modality for the management and

follow-up of such cases so that the mother can opt for

termination of pregnancy and the doctor can decide for a

vaginal delivery rather than caesarean section [8-10].

4. Conclusion

Although rare, facial and brain anomalies can be recog-

nized in high resolution ultrasonography probe is used.

Interorbital spaces, ventricular configuration and facial

morphology should be looked for in both the planes.

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