Focal Dermal Hypoplasia with a De novo Mutation p.E300* of PORCN Gene in a Male Infant

Novel insights into PORCN mutations, associated phenotypes and pathophysiological aspects

BACKGROUND

Goltz syndrome (GS) is a X-linked disorder defined by defects of mesodermal- and ectodermal-derived structures and caused by PORCN mutations. Features include striated skin-pigmentation, ocular and skeletal malformations and supernumerary or hypoplastic nipples. Generally, GS is associated with in utero lethality in males and most of the reported male patients show mosaicism (only three non-mosaic surviving males have been described so far). Also, precise descriptions of neurological deficits in GS are rare and less severe phenotypes might not only be caused by mosaicism but also by less pathogenic mutations suggesting the need of a molecular genetics and functional work-up of these rare variants.

RESULTS

We report two cases: one girl suffering from typical skin and skeletal abnormalities, developmental delay, microcephaly, thin corpus callosum, periventricular gliosis and drug-resistant epilepsy caused by a PORCN nonsense-mutation (c.283C > T, p.Arg95Ter). Presence of these combined neurological features indicates that CNS-vulnerability might be a guiding symptom in the diagnosis of GS patients. The other patient is a boy with a supernumerary nipple and skeletal anomalies but also, developmental delay, microcephaly, cerebral atrophy with delayed myelination and drug-resistant epilepsy as predominant features. Skin abnormalities were not observed. Genotyping revealed a novel PORCN missense-mutation (c.847G > C, p.Asp283His) absent in the Genome Aggregation Database (gnomAD) but also identified in his asymptomatic mother. Given that non-random X-chromosome inactivation was excluded in the mother, fibroblasts of the index had been analyzed for PORCN protein-abundance and -distribution, vulnerability against additional ER-stress burden as well as for protein secretion revealing changes.

CONCLUSIONS

Our combined findings may suggest incomplete penetrance for the p.Asp283His variant and provide novel insights into the molecular etiology of GS by adding impaired ER-function and altered protein secretion to the list of pathophysiological processes resulting in the clinical manifestation of GS.

Goltz syndrome in males: A clinical report of a male patient carrying a novel PORCN variant and a review of the literature

Here, we report a novel mosaic mutation in the PORCN gene in a male Goltz syndrome patient. We also compare the phenotypes of all reported males with a confirmed molecular diagnosis. This report serves to further clarify the phenotype of Goltz syndrome and suggests that expression in males varies.

Unilateral Focal Dermal Hypoplasia (Goltz Syndrome): Case Report and Literature Review

Focal dermal hypoplasia (FDH) or Goltz syndrome is a rare X-linked dominant multisystemic disease involving the ectoderm, mesoderm, and endoderm. About 95% of the cases appear de novo, and 90% of them are females. Recently, the studies revealed that FDH is caused by a mutation in the PORCN gene. We report a case of unilateral FDH or Goltz syndrome in a 16-year-old girl presenting with hypopigmented-reticulated atrophic macules and patches in a linear pattern distributed along the lines of Blaschko over the right side of the face and the right arm. Also she is having hypoplasia of the right breast with dental enamel abnormality and partial anodontia in the lower jaw. Sparse hair and partial alopecia on the right side (scalp, eyebrows, and eyelashes) were also observed.