Palmoplantar keratodermas

Gene: SMARCAD1

Green List (high evidence)

Comment on list classification: There are now more than 3 families reported in literature with monoallelic variants in SMARCAD1 and Huriez syndrome, which includes scleroatrophy of hands and feet, as well as palmoplantar hyperkeratosis. Some individuals with Basan syndrome also presented with palmoplantar keratoderma. Both syndromes are caused by monoallelic variants (deletions and splice variants) that affect the same splice site in the short skin-specific isoform of SMARCAD1. Based on available evidence, this gene can be promoted to Green at the next update.

Created: 28 Aug 2026, 3:46 p.m. | Last Modified: 28 Aug 2026, 3:46 p.m.

Panel Version: 4.19

HURIEZ SYNDROME
PMID: 35212137 Loh et al., 2022
Report of 3 Huriez syndrome (HRZ) families from Croatia, the Netherlands, and Germany. All seven HRZ patients displayed hypohidrosis, adermatoglyphia, and one patient developed squamous cell carcinoma at 32 years of age.
Family 1 - proband had mild hyperkeratosis of soles, thin palmar skin, and weak, pointed nails. Sanger seq revealed a heterozygous 11-bp deletion in SMARCAD1: g.94253671_94253682del.
Family 2 - male proband presented with scleroatrophy of hands, contracture of the little finger, sclerodactyly of distal extremities, hypoplastic nails, hypohidrosis. Proband and his affected mother were both het for a deletion affecting the SMARCAD1 donor splice site: g.94253673del
Family 3 - case previously described in PMID: 8731679 Hamm, 1996 and PMID: 29409814 Günther et al., 2018

PMID: 33400266 Loh et al., 2021
Report of a large pedigree with Huriez syndrome, caused by a large deletion that abrogates the skin‐specific isoform of SMARCAD1
Affected patients had evidence of scleroatrophy of the hands, some with subtle tapering of the fingers. There was ridging and hypoplasia of the nails. There was mild hyperkeratosis of the palms. On the soles of the feet, focal hyperkeratosis was seen. Good segregation evidence: NC_000004.12:g.94252297_94253585del was present in sampled affected individuals (n = 7) and was absent in unaffected individuals (n = 2).

PMID: 29409814 Günther et al., 2018
Report of 3 families with Huriez syndrome (congenital palmoplantar keratosis, scleroatrophic changes of the hands and feet, and an increased risk for cutaneous squamous cell carcinoma). SMARCAD1 variants in the skin specific isoform were highlighted : c.378+2T>C in family A, SMARCAD1 c.378+2_3insT in Family B, and c.363_378+2del in family C.

BASAN SYNDROME:
PMID: 34909722 Elhaji et al., 2021
Report of 2 families (Canadian and Dutch) with Basan syndrome:
Dutch family: mother and 2 children affected. Mother presented to dermatology clinic at 39 yrs - examination showed adermatoglyphia, hypohidrosis, tapered fingertips, painful palmoplantar punctate keratoderma and punctate hyperkeratosis. She had transient milia at birth. Onychorrhexis with deep longitudinal ridges and Beau lines were also seen. Her children, aged 7yrs and 10yrs, were similarly affected. In addition, callosities were observed on their palms, wrists, and soles of the feet. No other abnormalities regarding their hair, mouth, or teeth were identified. Variant c.374_378+7del was identified in SMARCAD1 short isoform.

Canadian family: total 12 individuals affected, with a clear dominant inheritance pattern. All 12 had adermatoglyphia, multiple transient milia on the face, and suffered from lack of sweat and susceptibility to heat strokes. 4/12 had webbed fingers. Proband twin neonates developed blistering near the ankles at birth that healed within days. Normal nails, hair, teeth, and skin pigmentation in all patients.
Complex rearrangement was identified in this family, including a deletion of ~50.9 kb and an inverted duplication of ~23.4 kb. The deletion encompasses exons 1‒9 of SMARCAD1 long isoform and exon 1 of the short isoform and includes the first exon of the long noncoding RNA (LOC101929210).

PMID: 30289605 Valentin et al., 2018
Case report of a 10 day old male with bilateral heel erosions, which had been bullae at birth. He developed no further bullae or erosions. He was also noted to have innumerable congenital milia around the face, adermatoglyphia of his finger and toes, onychorrhexis, hyperpigmented macules on the hands and feet, and a waxy keratoderma with fine wrinkling of the palms and soles. No hair or teeth anomalies present. Proaband was het for NM_001254949.1:c.-10 + 2 T > G, in the donor splice site of exon 1 of the skin-specific isoform.

PMID: 26932190 Li et al., 2016
Chinese family with Basan syndrome. Some patients presented with hyperpigmentation and knuckle pads in addition to classical symptoms of rapidly healing congenital acral bullae, congenital milia and lack of fingerprints. Hair, eyebrows, eyelashes, teeth and nails were all normal. Hypohidrosis was also noted in all 8 affected individuals. Hyperpigmentation was noted in 5/8 patients, and contractures were seen in all 8 individuals, though only mild in 5. WGS of the proband identified a heterozygous c.378+1G>T variant in SMARCAD1 (same as in PMID: 21820097). Variant co-segregated with disease, maximal LOD score was 3.01.

NON-SYNDROMIC ADERMATOGLYPHIA:
PMID: 32769257 Alruwaili & Hai, 2019
Report of a 60yo Saudi Arabian man with isolated adermatoglyphia, het for c.378+1G>T in SMARCAD1 short isoform.

PMID: 24909267 Nousbeck et al., 2014
3 families with isolated adermatoglyphia and heterozygous mutations in SMARCAD1 (c.378 + 2T > C, c.378 + 5G > C and c.378 + 1G > A)

PMID: 21820097 Nousbeck et al., 2011
Report of a large Swiss kindred presenting with autosomal-dominant adermatoglyphia (9 affected, 7 unaffected). Linkage analysis gave a LOD score of 2.85. Sequencing detected a heterozygous variant in the skin-specific SMARCAD1 short isoform: c.378+1G>T.

N.B.: PMID: 35592705 Xiong et al., 2022 - Basan syndrome family; ARTICLE RETRACTED

SMARCAD1 is associated with AD Adermatoglyphia, MIM:136000; AD Basan syndrome, MIM:129200; AD Huriez syndrome, MIM:181600 (OMIM accessed 28th Aug 2026).
Sources: Literature

Created: 28 Aug 2026, 3:41 p.m.

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted

Phenotypes
Adermatoglyphia, OMIM:136000; Basan syndrome, OMIM:129200; Huriez syndrome, OMIM:181600

Publications

• 21820097
• 24909267
• 26932190
• 29409814
• 30289605
• 33400266
• 34909722
• 35212137