Hi Icthyosis is a skin condition and it is hereditary or acquired.
Hereditary ichthyosis vulgaris and acquired ichthyosis vulgaris, members of a group of cutaneous disorders of keratinization, appear similar both clinically and histologically. Hereditary ichthyosis vulgaris is an autosomal dominant genetic disorder first evident in early childhood. It is the most common form of ichthyosis, accounting for more than 95% of ichthyosis cases. It is caused by altered profilaggrin expression leading to scaling and desquamation. Hereditary ichthyosis is also associated with atopy.Acquired ichthyosis, usually appearing for the first time in adulthood, is a nonhereditary condition associated with internal disease. Acquired ichthyosis is rare and must be viewed as a marker of systemic disease, including malignancy. Cases have been attributed to the use of certain medications.Hereditary ichthyosis vulgaris is a chronic disorder that may improve with age but often requires continuous therapy. The severity of acquired ichthyosis usually depends on the status of the underlying systemic condition. The main approach to treatment of both conditions includes hydration of the skin and application of an ointment to prevent evaporation. Hydration promotes desquamation by increasing hydrolytic enzyme
The prognosis for hereditary ichthyosis vulgaris is excellent. Many patients experience improvement of symptoms with age. The prognosis for acquired ichthyosis vulgaris depends on the severity of the underlying systemic disease.
So as you say your mother is also have this ,it is probably hereditary and prognosis is good but it need prolonged treatment.