Hypotonia, developmental delay and features of scalp-ear-nipple syndrome in an inbred Arab family

Scalp-Ear-Nipple syndrome: first report of a Potassium channel tetramerization domain-containing 1 in-frame insertion and review of the literature

OBJECTIVES

Pathogenic missense variants in the potassium channel tetramerization domain-containing 1 (KCTD1) gene are associated with autosomal dominant Scalp-Ear-Nipple syndrome (SENS), a type of ectodermal dysplasia characterized by aplasia cutis congenita of the scalp, hairless posterior scalp nodules, absent or rudimentary nipples, breast aplasia and external ear anomalies. We report a child with clinical features of an ectodermal dysplasia, including sparse hair, dysmorphic facial features, absent nipples, 2-3 toe syndactyly, mild atopic dermatitis and small cupped ears with overfolded helices. We also review the published cases of SENS with molecularly confirmed KCTD1 variants.

METHODS AND RESULTS

Using whole-exome sequencing, we identified a novel, de novo in-frame insertion in the broad-complex, tramtrack and bric-a-brac (BTB) domain of the KCTD1 gene. By comparing to the previously reported patients, we found that our patient's clinical features and molecular variant are consistent with a diagnosis of SENS.

CONCLUSIONS

This is only the 13th KCTD1 variant described and the first report of an in-frame insertion causing clinical features, expanding the mutational spectrum of KCTD1 and SENS.

Scalp-ear-nipple syndrome: a case report

The scalp-ear-nipple (SEN) syndrome is an infrequent congenital disease. Its main features are scalp defects, malformed ears, and absence of nipples. Most of the reported cases are autosomal dominant. We report on a patient suffering SEN syndrome with possible autosomal recessive inheritance. It is concluded that SEN syndrome should be recognized as an entity with genetic heterogeneity once there is evidence of different genetic manner of inheritance described in this disease.

Mutations in KCTD1 cause scalp-ear-nipple syndrome

Scalp-ear-nipple (SEN) syndrome is a rare, autosomal-dominant disorder characterized by cutis aplasia of the scalp; minor anomalies of the external ears, digits, and nails; and malformations of the breast. We used linkage analysis and exome sequencing of a multiplex family affected by SEN syndrome to identify potassium-channel tetramerization-domain-containing 1 (KCTD1) mutations that cause SEN syndrome. Evaluation of a total of ten families affected by SEN syndrome revealed KCTD1 missense mutations in each family tested. All of the mutations occurred in a KCTD1 region encoding a highly conserved bric-a-brac, tram track, and broad complex (BTB) domain that is required for transcriptional repressor activity. KCTD1 inhibits the transactivation of the transcription factor AP-2α (TFAP2A) via its BTB domain, and mutations in TFAP2A cause cutis aplasia in individuals with branchiooculofacial syndrome (BOFS), suggesting a potential overlap in the pathogenesis of SEN syndrome and BOFS. The identification of KCTD1 mutations in SEN syndrome reveals a role for this BTB-domain-containing transcriptional repressor during ectodermal development.

Finlay-Marks syndrome: report of two siblings and review of literature

Finlay-Marks syndrome (scalp-ear-nipple syndrome), is the infrequently reported association of scalp aplasia, malformed ears, and breast abnormalities varying from small nipples to complete absence of breasts. Other manifestations are variable and some of them resemble ectodermal dysplasia and include dystrophy of nails and teeth, sparse hair, decreased sweating, and cutaneous syndactyly of digits. Renal anomalies have been reported in some patients leading to hypertension and renal insufficiency. Most reported patients have been sporadic but familial occurrences following an autosomal dominant pattern of inheritance have been reported. We report on two affected siblings, of whom one died in the neonatal period due to renal failure. Two affected siblings born to non-affected parents may suggest an autosomal recessive inheritance.