Cutaneous photosensitivity with a likely genetic cause

Gene: DNA2

Green List (high evidence)

Comment on list classification: There are now 8 unrelated patients reported in literature with biallelic DNA2 variants (including a recurrent deep intronic variant) and Rothmund-Thomson syndrome, with cutaneous photosensitivity and bullae being consistent features. Hence, this gene can be promoted to Green at the next update.

Created: 11 Sep 2026, 9:14 a.m. | Last Modified: 11 Sep 2026, 9:14 a.m.

Panel Version: 3.20

ROTHMUND-THOMSON SYNDROME:
PMID: 37055165 Di Lazzaro Filho et al., 2023
OMIM 620819 summary: Study reported 8 children from 7 families with Rothmund-Thomson syndrome and mutation in the DNA2 gene. 6 of the children were Brazilian and 2 were sibs of Swiss/Portuguese ancestry. Clinical findings included severe growth failure, with some individuals showing signs suggestive of growth hormone or combined pituitary hormone deficiency; widespread poikiloderma; cutaneous photosensitivity and bullae; sparse hair, eyebrows, and eyelashes; dystrophic nails; congenital cataracts and other ocular anomalies, including glaucoma, microphthalmia, and corneal opacities, with Peters anomaly and optic atrophy in 1 patient each; craniofacial dysmorphisms, including severe microcephaly; and skeletal anomalies, including osteopenia, platyspondyly, flared and/or irregular metaphyses, and short metacarpals and phalanges.

6/6 patients above age 2 years had short stature of more than 2 SDS below mean (-4.3 to -8.1SDS). Microcephaly was not severe at birth: between -0.3 to -2.3SDS, but progressed in all patients and was more than -3SDS in unrelated patients.
All 7 probands harboured a recurrent DNA2: c.588–2214A>G intronic variant, in addition to other DNA2 variants in trans: 5 individuals had intragenic exon deletions, one harboured missense variant c.143T>C, p.Leu48Pro (not reported in gnomaD), and sibs in Family 7 had a frameshift variant.

PMID: 40693833 Ay et al., 2025
Report of a female Turkish proband with Rothmund-Thomson syndrome and comp het DNA2 variants: deep intronic c.588-2214A>G and missense c.2519 T>C, Leu840Pro (not in gnomAD v4). She presented with hallmark features of the syndrome: short stature, poikiloderma, corneal dystrophy, bilateral cataracts, skin photosensitivity and blistering, hand contractures, dystrophic nails. Parents are non-consanguineous. Microcephaly not reported; her height was 76cm (-6.3SDS) at 4 yo.

This gene is associated with AR Rothmund-Thomson syndrome, type 4, OMIM:620819 in OMIM as of 11th Sept 2026.
Sources: Literature

Created: 11 Sep 2026, 9:07 a.m.

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Phenotypes
Rothmund-Thomson syndrome, type 4, OMIM:620819; Seckel syndrome 8, OMIM:615807; Rothmund-Thomson syndrome type 4, MONDO:0970950; Seckel syndrome 8, MONDO:0014350

Publications

• 37055165
• 40693833