Retinal disorders

Gene: MAN2B1

Green List (high evidence)

The rating of this gene has been updated to green following NHS Genomic Medicine Service approval.

Created: 24 Feb 2025, 5:49 p.m. | Last Modified: 24 Feb 2025, 5:49 p.m.

Panel Version: 7.8

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Green List (high evidence)

MAN2B1 variants have been associated with Mannosidosis, alpha-, types I and II, (OMIM:248500).
Matlach et al (PMID: 29859105) present a detailed study of the ocular manifestations in OMIM:248500. Using posterior segment examination, fundus photography, and Spectral-Domain optical coherence tomography (SD-OCT) imaging, in a cohort of 32 patients, the authors were able to show the following: Tapeto-retinal degeneration with bone spicule formations in the peripheral retina or macular changes in three patients (9.4%) on funduscopy (two had optic nerve atrophy). Thinning of the outer retinal layer was seen in six patients (18.8%) using OCT. Optic nerve atrophy was seen in six patients (18.8%)(four with partial atrophy). A further two patients (6.3%) had partial optic nerve atrophy with no retinal abnormalities on funduscopy. Cataract was seen in two patients (6.3%), corneal haze was seen in two patients (6.3%). Six patients (18.8%) had manifest strabismus, four (12.5%) nystagmus, and in five patients (15.6%) impaired smooth pursuit eye movements were seen. This study emphasized the importance of detailed examinations, to be able to diagnose early signs of disease.

Created: 1 Oct 2024, 3:46 p.m. | Last Modified: 1 Oct 2024, 3:46 p.m.

Panel Version: 6.12

Green List (high evidence)

Retinal dystrophy can be a feature of the systemic alpha-mannosidosis phenotype, and can be the presenting feature in apparent non-syndromic retinal dystrophy (one individual in the Moorfields cohort)
Sources: Literature

Created: 25 Sep 2024, 7:25 p.m.

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Phenotypes
Retinal dystrophy

Publications

• PMID:29859105

Mode of pathogenicity
Other