Ms Sharif's husband and daugter were in jail at the time of her passing. Nawaz's party leadership said it hopes that they will be granted bail.
She was elected as an MP in 2017 after standing in for Nawaz Sharif. She was suffering from cancer.
She got engaged to Mian Nawaz Sharif during her Masters programme.
"COAS expresses his grief and heartfelt condolences to the bereaved family on sad demise of Begum Kulsoom Nawaz".
Kulsoom Sharif was briefly a member of parliament after she won her husband's former seat in a by-election after the Supreme Court disqualified him.
After the Supreme Court disqualified Nawaz Sharif from his seat a year ago, Kulsoom was elected to Lahore's NA-120 constituency in a bye-poll.
Mr Butt's family has Kashmiri origins and has deep roots in Lahore city, while Razia Begum hailed from a well-known family of wrestlers from Amritsar, India, who migrated to Lahore in 1947. She will be laid to rest at Jati Umra in Lahore however, day and time are yet to be revealed.
His first term as Prime Minister ended in July 1993.
Both her sons Hassan and Hussain reside in the United Kingdom and cared for her while Nawaz and Maryam attended near daily hearings of the corruption trial.
Sharif was ousted from the premiership a month before his wife's diagnosis.
Her first direct exposure to the harsh political landscape of Pakistan came in October 1999 when her husband's government was toppled and he was imprisoned.
Kulsoom was arrested by the military and immediately shifted to her local residence.
Leaders from across the political spectrum in Pakistan sent in their best wishes for Kulsoom during the length of her illness.
"She had a very motherly behaviour not only towards the party members but people in general". She was under treatment at London's Harley Street Clinic since July previous year.
Nawaz and Maryam were arrested on July 13 upon their arrival in Lahore and are now serving a jail sentence in Adiala Jail. "It was Begum Kulsoom who broke the family's long-held tradition of not allowing women to foray into politics". "They had to leave her behind, I don't know what they'll be going through right now". She then moved to London for medical care.
The news was confirmed by PML-N president Shehbaz Sharif. But it soon transpired that she had been diagnosed with lymphoma.