Elisabeth Mortensen, who plays Mathilde Nielsen, the mother of Astrid, in several episodes throughout the series, is, in fact, the mother of Sara Mortensen, the actress who plays Astrid.
Astrid wears variations of the exact same clothes in every scene, only the colours differ
On a similar theme is recent excellent Korean mini series Extraordinary Attorney Woo, which also features a highly intelligent but unorthodox autistic central character.
In "The Missing Link," several characters are named after Ghostbusters characters--Peter Venkman, Dana Barrett, Ray Stantz.
Astrid is played by French-Norwegian actress Sara Mortensen, born 10 December 1979, the same year as senior colleague Raphaëlle. She is trilingual.