Rare Association of Isolated Microphthalmia with Anorectal Malformation.

Anorectal malformations (ARMs) have coexisting congenital anomalies. These can affect the overall prognosis. Anomalous craniofacial associations are less common. Recently, we managed two patients of ARM associated with unilateral microphthalmia, without any other major systemic anomalies. This was found to be a rare association on extensive literature search. Copyright:

INTRODUCTION

Anorectal malformation (ARM) is a complex group of congenital anomalies. Abnormal development of allantois, hindgut, and Müllerian duct can cause partial/incomplete malformation of urorectal septum. Incidence is around 1 in 4000–5000 live births with isolated incidence of around 35%–40%. Approximately 60%–65% have other associated systemic defects.[1] Chromosomal anomalies can be seen in about 7%–10% with occasional evidence of familial association.[2] Syndromic association with coexisting birth defects has an incidence of around 50%. Overall, quality of life as well as prognosis in such patients depends on the severity of associated anomalies.[3] Thus, all patients with a diagnosis of ARMs must be examined meticulously to detect coexisting anomalies. We recently managed two female infants with ARM associated with unilateral microphthalmia. This combination of anomalies is rarely reported and thus needs to be documented.

CASE REPORT

The first infant was a full-term female child, born out of a nonconsanguineous marriage, with birth weight of 2.3 kg, diagnosed to have imperforate anus with rectovestibular fistula. Echocardiography noted mild left ventricular hypertrophy. On clinical examination, she was found to have right microphthalmia without any other ocular abnormality or vision anomaly. She did not need any treatment for same. She underwent a primary rectal pull-through procedure and recovered well [Figure 1].

Figure 1

Patient 1 with microphthalmia

The second patient was a preterm female child, product of nonconsanguineous marriage, with birth weight of 2.8 kg. She was also diagnosed with imperforate anus and rectovestibular fistula. She was found to have right microphthalmia with no other ocular anomalies. She did not suffer from any other associated anomalies and was deemed fit for surgical intervention for ARM. She underwent staged procedure – colostomy was done initially followed by posterior sagittal anorectoplasty and then colostomy closure with a gap of 2–3 months between all the procedures. Patient is currently on regular follow-up and thriving well and does not suffer from any vision anomalies [Figure 2].

Figure 2

Patient 2 with right microphthalmia

Both patients had a primary diagnosis of anorectal malformation with rectovestibular fistula. They were extensively evaluated and were found to have microphthalmia without any other major systemic anomalies.

DISCUSSION

Anorectal malformation is a common congenital anomaly diagnosed at birth. Patients may have associated anomalies that can be broadly classified as major and minor. According to a large study done, systems showing common involvement include genitourinary (45%–50%), musculoskeletal (40%–45%), craniofacial (30%–35%), cardiovascular (27%), gastrointestinal (18%), respiratory anomalies (13%), and central nervous system anomalies (12%).[4] Genetics in ARM are highly complex and many candidate genes have been identified. They are classified as “field defects,” as they are a result of complex genetic interactions.[5] These multiple anomalies can be syndromic or nonsyndromic, associated with chromosomal abnormalities or due to environmental influence.

As per classification done in a study based on the European Surveillance of Congenital Anomalies for ARM-associated anomalies, the associations are categorized as follows:

VACTERL association

Multiple congenital anomalies with two/more defects without a recognizable pattern

Syndromes with a known cause (teratogenic, monogenic, or chromosomal)

Recognized sequences and syndromes.

As critical organogenesis happens before the 6th–7th week, the defect is assumed to have occurred in early gestation. Eye development begins around the 3rd week of gestation. Two small grooves develop on forebrain known as sulci or optic grooves. Microphthalmia is rare congenital anomaly with isolated incidence of about 1 in 10,000 births.[6] It can occur if infection is acquired during pregnancy or could have genetic transmission, but the exact cause is unknown. Maternal age over 40 years or history of multiple births as well as low gestational age of infant or low birth weight are other associated risk factors. Complex microphthalmia is the presence of other associated ocular disorders. These include anterior segment defects such as sclerocornea or posterior segment involvement such as retinal dysplasia and persistent hyperplastic primary vitreous. Learning disabilities are associated in few cases. Multidisciplinary management involves pediatricians and ophthalmologists with occasional involvement of clinical geneticists, if syndromic association is suspected. Treatment aims at sustaining existing vision and improving cosmesis by the growth of bony orbit and soft-tissue stimulation and is usually started early, within weeks of life to improve the overall development of such patients. Mild-to-moderate forms can be managed conservatively with shapers/conformers. Severe cases require surgical remodeling for endo-orbital volume replacement that can be achieved with expanders, grafts, or implants as well as the reconstruction of soft tissue. Visual potential depends on the development of retina and other ocular features.[7]

Once ocular anomaly is suspected in a patient with ARM, assessment should be done by a pediatric ophthalmologist as soon as possible. Both eyes should be examined especially in case of unilateral ocular anomaly, as the opposite eye might also have subtle anomalies. Ultrasound of the eye and orbit evaluates the inner structure of the eye and determines axial length in cases of microphthalmia. Vision assessment by flash visual-evoked potential will establish the presence of vision, establish the level of acuity, and detect any optic nerve dysfunction. Retinal dysfunction can be assessed by electroretinogram. Genetic evaluation can be done by chromosome analysis for the testing of particular genes. Management of such cases has multidisciplinary approach. Surgical management of both ARM and microphthalmia can be done in conjunction as per the severity of the condition and clinical stability of the patient. In unilateral cases, the asymmetry may become more pronounced as the child grows. In severe microphthalmia, early socket expansion is started soon after birth to minimize facial deformity. Sequential socket expansion is done for its progressive growth until symmetry is achieved or more expansion is not possible. If the axial length of microphthalmic eye is <16 mm, it is unlikely to promote normal growth and socket expansion is required. After initial socket expansion over the first 5 years of life, a yearly review should be done to assess growth.[8]

Ocular anomalies such as iris coloboma, microphthalmia, and cat eye syndrome (CES) have been reported with ARM. A large series, including 103 patients with ARMs with associated anomalies, by Cho et al., observed malformation syndromes in only three patients, which consisted of Opitz Syndrome, CES, and Potter syndrome type 1.

Most commonly, CES occurs as a triad of iris coloboma with preauricular anomalies and anal atresia. Less frequently, other ocular features can occur, such as unilateral microphthalmia, cornea clouding, aniridia, or cataract. The most common genetic defect is a supernumerary small bisatellited marker chromosome that causes partial tetrasomy of 22pter-22q11. The management is multidisciplinary as it depends on the presenting symptoms in each case. Severe malformations can have a higher mortality rate in early infancy, but in general, life expectancy is not greatly reduced.[9]

Isolated association between ARM and unilateral microphthalmia was not reported on extensive literature search. Thus, this association could be attributed to a rare phenotypic variation of CES or incidental presence of two isolated developmental defects.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/ her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.