Rare Eye Findings in a Case of Sotos Syndrome

Discussion

Soto’s syndrome also known as cerebral gigantism is a rare disorder of growth and development with characteristic facial gestalt, non-progressive neurologic disorder, and normal endocrine function (Nalini A 2008). Aapproximately, 1 in 5,000 or 0.02% of 4,400 people in the United States have Soto’s syndrome which includes reported cases and undiagnosed cases. From our MEDLINE search, the exact prevalence still remains doubtful. It is a non-hormone mediated accelerated growth disorder, which mimics pituitary gigantism, but with no neuro endocrine dysfunction (Hook EB 1967; Nalini A 2008).Large birth size with marked linear growth in the first few years of life, advanced bone age, and developmental delay are major diagnostic features in the syndrome- (Cole TR et al 1994). Our patient had typical clinical features with additional associations.

Many published articles have reported cataracts, and interestingly nuclear and cortical cataracts have been described but not polar cataract. Yeh et al. (1978) has described cortical cataracts as early as 1978, and Koenekoop et al. (1995) described nuclear cataracts in 1995-(Michael T et al 2000).

In a study performed on a large population from several colleges and schools of optometry and various clinics of optometrists and ophthalmologists, it was found that moderate-to-high refractive error, nystagmus, and strabismus were commonly associated with Soto’s syndrome (Maino DM et al 1994).Our patient, in addition, had the rare association of keratoconus.

The patho-physiology is not well understood, although it is attributed to disordered collagen and elastin synthesis, and shares a common pathway with various syndromes like Beckwith-Wiedemann, Klippel-Feil, Trenauney, and Weavers syndromes (Douglas et al. 2003; Nalini and Biswas, 2008).The four major diagnostic criteria were established in 1994 by Cole and Hughes (1994) based on the systematic assessment of 41 typical cases: overgrowth with advanced bone age macrocephaly, characteristic facial appearance, and learning difficulties.

(Geneviève Baujat 2007; Cole TR 1994). These clinical criteria remained the cornerstone for the diagnosis of Soto’s until 2002. Discovery of a mutant gene Nuclear SET Domain 1 (NSD1) is currently accepted as the cause of this disorder (Douglas et al. 2003 and 2005). Tatton-Brown (2004) analysed clinical features of a large series of more than 200 Soto’s syndrome cases with proven abnormalities in NSD1and also reported possible link with toxaemia in pregnancy which was evident in our patient’s history (Geneviève Baujat  2007; Opitzet al 1998). Unfortunately, no genetic karyo typing was performed on our patient.

Our report provides additional evidence of other rare ophthalmological association with Soto’s Syndrome. Even though this is a single case presentation, it is important to highlight to the managing ophthalmologists that keratoconus and polar cataract could possibly be rare ocular features of this syndrome. This condition definitely warrants an early detection and careful monitoring. Appropriate treatment should be instituted to restore their best visual acuity.

Conclusion

Although relatively few descriptions of ocular findings are found in the existing literature, our report provides additional evidence that these patients can develop treatable ocular problems (Michael T et al 2000).These patients should be examined routinely to allow for early detection and treatment of potential ocular problems;-keratoconus and cataract. This ultimately would be invaluable in the prevention of amblyopia.

Figure 4: Keratometry Demonstrating Keratoconus.

Figure 5: Ventriculomegaly on MRI