Hereditary fibrosing poikiloderma with tendon contractures, myopathy, and pulmonary fibrosis (POIKTMP [MIM 615704]) is characterized by the skin findings of poikiloderma (typically beginning in the first six months and mainly localized to the face), hypohidrosis with heat intolerance, mild lymphedema of the extremities, chronic erythematous and scaly skin lesions on the extremities, sclerosis of the digits, and mild palmoplantar keratoderma. Scalp hair, eyelashes, and/or eyebrows are typically sparse.
Muscle contractures are usually seen in childhood and can be present as early as age two years. The majority of affected individuals develop progressive weakness of the proximal and distal muscles of all four limbs.
Some adults develop progressive interstitial pulmonary fibrosis, which can be life-threatening within three to four years after respiratory symptoms appear.
Other features are exocrine pancreatic insufficiency, liver impairment, hematologic abnormalities and relative short stature.
Prevalence
POIKTMP is a very rare disease. The prevalence is unknown. To date only 28 individuals with identified FAM111B mutations have been reported. The condition is thought to be ubiquitous and is likely underdiagnosed.
Inheritance
POIKTMP is inherited in an autosomal dominant manner. Poikiloderma and hypotrichosis are fully penetrant features. The severity of the features (e.g., skin or muscle abnormalities) can vary. Intrafamilial clinical variability has been observed (Khumalo, et al. 2006, Seo, et al. 2016).