Mosaic skin disorders - deep sequencing

Gene: KITLG

Green List (high evidence)

Mosaic

Created: 31 Oct 2025, 1:59 p.m. | Last Modified: 31 Oct 2025, 1:59 p.m.

Panel Version: 3.1

Mode of inheritance
Other

Phenotypes
Blaschkolinear hyperpigmentation

Publications

• PMID: 28257793

Comment on list classification: Upgrading rating from Grey (removed) to Amber. One patient has been reported with congenital linear and mottled hyperpigmentation on trunk and limbs due to a de novo postzygotic KITLG variant (p.Asp110Gly). Immunohistochemistry suggested that this variant results in increased epidermal expression of KITLG and an increased number of epidermal melanocytes (PMID: 28257793).

The germline phenotype (OMIM:145250) is more likely to be tested under R236 and as there is only one somatic case with a mosaic presentation, suggesting an Amber rating while awaiting further evidence (added 'watchlist' tag).

Created: 3 Oct 2023, 10:54 a.m. | Last Modified: 3 Oct 2023, 10:54 a.m.

Panel Version: 2.32

Green List (high evidence)

Good evidence to support causation in familial progressive hyper- and hypopigmentation (FPHH) - green on pigmentary disorders panel. Less evidence to support linear and whorled nevoid hypermelanosis (LWNH) - single case in PMID 28257793, but important as differential for mosaic pigmentary disorders as no brain involvement unlike other similarly presenting disorders (therefore no brain scanning mandated following KITLG diagnosis).

Created: 3 May 2023, 3:17 p.m. | Last Modified: 3 May 2023, 3:17 p.m.

Panel Version: 2.1

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted

Phenotypes
Linear and whorled nevoid hypermelanosis (LWNH); familial progressive hyperpigmentation with or without hypopigmentation (FPHH)(MIM 145250)

Publications

• 28257793

Green List (high evidence)

This gene was part of an initial gene list collated by Thomas Cullup, GOSH and Veronica Kinsler, UCL, 25.Jan.2019 on behalf of the GMS Skin Specialist Test Group. Gene Symbol submitted: KITLG; Suggested initial gene rating: Green; Evidence for inclusion: none provided; Evidence for exclusion: none provided; Technical notes (e.g. non-coding/CNV mutations requiring coverage?): none provided.

Created: 31 Jan 2019, 2:50 p.m.