The MARVEL domain is a 130 amino acid motif that contains four transmembrane helices, both of which have cytoplasmic N- and C-terminal regions. MARVEL domain-containing proteins are thought to participate in tight junction regulation, the biogenesis of vesicular transport carriers and in cholesterol-rich membrane apposition events. Pantophysin, also known as SYPL1 (synaptophysin-like protein 1) or H-SP1, is a 259 amino acid multi-pass membrane protein that localizes to melanosomes and vesicles, as well as to the cytoplasm, and contains one MARVEL domain. Expressed as multiple alternatively spliced isoforms, pantophysin is present in tissues throughout the body where it may play a role in vesicle trafficking and protein transport. The gene encoding pantophysin maps to human chromosome 7, which houses over 1,000 genes and comprises nearly 5% of the human genome. Defects in some of the genes localized to chromosome 7 have been linked to Osteogenesis imperfecta, Williams-Beuren syndrome, Pendred syndrome, Lissencephaly, Citrullinemia and Shwachman-Diamond syndrome.