A macular coloboma is an area of 2-6 disk diameters in which there is total or considerable chorioretinal maldevelopment, often with extasia of the underlying sclera which produces the white appearance visible ophthalmoscopically (summary by Phillips, 1970).

Early-onset neurodegeneration in the human retina can lead to Leber congenital amaurosis (LCA), the most severe human form of inherited photoreceptor-neuron degeneration resulting in congenital blindness, with an incidence of approximately 1 in 80,000 (summary by Koenekoop et al., 2012). NMNAT1 mutations have been observed to cause severe and rapidly progressive macular degeneration, leading to severe central atrophy with an appearance of congenital macular coloboma in the neonatal period, as well as an unusual early-onset atrophy of the optic nerve (Perrault et al., 2012). Some patients present with later onset and milder phenotype than typical LCA (Kumaran et al., 2021). For a general discussion of the phenotypic and genetic heterogeneity in Leber congenital amaurosis, see LCA1 (204000).

A macular coloboma is an area of 2-6 disk diameters in which there is total or considerable chorioretinal maldevelopment, often with extasia of the underlying sclera which produces the white appearance visible ophthalmoscopically (summary by Phillips, 1970).

Macular coloboma-cleft palate-hallux valgus syndrome is characterised by the association of bilateral macular coloboma, cleft palate, and hallux valgus. It has been described in a brother and sister. Pelvic, limb and digital anomalies were also reported. Transmission is autosomal recessive.

Leber congenital amaurosis comprises a group of early-onset childhood retinal dystrophies characterized by vision loss, nystagmus, and severe retinal dysfunction. Patients usually present at birth with profound vision loss and pendular nystagmus. Electroretinogram (ERG) responses are usually nonrecordable. Other clinical findings may include high hypermetropia, photodysphoria, oculodigital sign, keratoconus, cataracts, and a variable appearance to the fundus (summary by Chung and Traboulsi, 2009). For a general description and a discussion of genetic heterogeneity of LCA, see 204000.

MCOPCB9 is characterized by microphthalmia and coloboma (Aldahmesh et al., 2012). MCOPS15 is characterized by microphthalmia and/or coloboma, with developmental delay in which speech appears to be more severely affected than motor abilities. Additional ocular anomalies that have been observed include ptosis, keyhole-shaped pupils, microcornea, sclerocornea, and anterior segment dysgenesis (Chassaing et al., 2016; Stephen et al., 2018; Singh et al., 2019). For a discussion of genetic heterogeneity of colobomatous microphthalmia, see MCOPCB1 (300345). For a discussion of genetic heterogeneity of syndromic microphthalmia, see MCOPS1 (309800).

HOMG5 is an autosomal recessive disorder characterized by severe renal magnesium wasting, progressive renal failure, and nephrocalcinosis. Some patients also have severe visual impairment. Amelogenesis imperfecta has been reported in some patients (summary by Konrad et al., 2006 and Yamaguti et al., 2017). For a discussion of genetic heterogeneity of renal hypomagnesemia, see 602014.

SHILCA is characterized by early-onset retinal degeneration in association with sensorineural hearing loss, short stature, vertebral anomalies, and epiphyseal dysplasia, as well as motor and intellectual delay. Delayed myelination, leukoencephalopathy, and hypoplasia of the corpus callosum and cerebellum have been observed on brain MRI (Bedoni et al., 2020).