Inheritance is mostly autosomal dominant but autosomal recessive forms have been described as well.
[thieme-connect.com]
[5, 12, 13, 14, 15, 16, 17, 18, 19] Most cases of pure HSP are autosomal dominant, whereas complicated forms tend to be autosomal recessive.
[emedicine.medscape.com]
[…] for dominant and X-linked forms of HSP will certainly be even greater in autosomal recessive forms.
[jamanetwork.com]