"UNKNOWN" value in MH Domain,

Hi CDISC,

I'm currently working on Legacy Study with Data having no proper structure(Pre-CDISC format).

In MH Domain, I have data like "Yes","No","Unknown", "Free text(for Suppqual)". After transposing the data, I got all MH variables -->MHTERM
eg:

CARDIAC DISEASES----------------> 'Yes' or 'No' or 'UNKNOWN'
HYPERTENSION---------------------> 'Yes' or 'No' or 'UNKNOWN'
RESPIRATORY DISEASE------------> 'Yes' or 'No' or 'UNKNOWN'
LIVER DISEASE ---------------------> 'Yes' or 'No' or 'UNKNOWN'
DIABETES----------------------------> 'Yes' or 'No' or 'UNKNOWN'
RENAL DISEASES-------------------> 'Yes' or 'No' or 'UNKNOWN'
OTHER--------------------------------> 'Yes' or 'No' or 'UNKNOWN', "FREE TEXT(SPECIFY OTHER)"

I took "FREE TEXT(SPECIFY OTHER)" into SUPPMH and linking with MHSEQ, but I don't know, how to handle 'UNKNOWN' value, I can't take it into SUPPMH as linking will be missing with Parent domain(USUBJID/MHTERM), Can you please suggest me how to proceed.

Thanks in advance,

Srinath