# EDGAR Filing Document

**Accession Number:** 0001780065
**File Stem:** 0000899243-23-000461
**Filing Date:** 2023-1
**Character Count:** 16728
**Document Hash:** 00ea795ab553bd2485a688024d4a51ea
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000899243-23-000461.hdr.sgml**: 20230103

**ACCESSION NUMBER**: 0000899243-23-000461

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20221229

**FILED AS OF DATE**: 20230103

**DATE AS OF CHANGE**: 20230103

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Atlas Venture Fund X, L.P.
- **CENTRAL INDEX KEY:** 0001628098
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39438
- **FILM NUMBER:** 23504198

**BUSINESS ADDRESS:**
- **STREET 1:** 400 TECHNOLOGY SQUARE
- **STREET 2:** 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
- **BUSINESS PHONE:** 857-201-2700

**MAIL ADDRESS:**
- **STREET 1:** 400 TECHNOLOGY SQUARE
- **STREET 2:** 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Atlas Venture Associates X, LLC
- **CENTRAL INDEX KEY:** 0001742765
- **STATE OF INCORPORATION:** DE

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39438
- **FILM NUMBER:** 23504196

**BUSINESS ADDRESS:**
- **STREET 1:** 400 TECH. SQ.
- **STREET 2:** 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
- **BUSINESS PHONE:** 857-201-2700

**MAIL ADDRESS:**
- **STREET 1:** 400 TECH. SQ.
- **STREET 2:** 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** ATLAS VENTURE ASSOCIATES X, L.P.
- **CENTRAL INDEX KEY:** 0001742766
- **STATE OF INCORPORATION:** DE

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39438
- **FILM NUMBER:** 23504197

**BUSINESS ADDRESS:**
- **STREET 1:** 400 TECHNOLOGY SQ.
- **STREET 2:** 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
- **BUSINESS PHONE:** 857-201-2700

**MAIL ADDRESS:**
- **STREET 1:** 400 TECHNOLOGY SQ.
- **STREET 2:** 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Atlas Venture Opportunity Fund I, L.P.
- **CENTRAL INDEX KEY:** 0001759241
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39438
- **FILM NUMBER:** 23504195

**BUSINESS ADDRESS:**
- **STREET 1:** 400 TECHNOLOGY SQUARE, 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
- **BUSINESS PHONE:** 857-201-2700

**MAIL ADDRESS:**
- **STREET 1:** 400 TECHNOLOGY SQUARE, 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Atlas Venture Associates Opportunity I, L.P.
- **CENTRAL INDEX KEY:** 0001780065
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39438
- **FILM NUMBER:** 23504194

**BUSINESS ADDRESS:**
- **STREET 1:** 400 TECHNOLOGY SQUARE
- **STREET 2:** 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
- **BUSINESS PHONE:** 857-201-2700

**MAIL ADDRESS:**
- **STREET 1:** 400 TECHNOLOGY SQUARE
- **STREET 2:** 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Atlas Venture Associates Opportunity I, LLC
- **CENTRAL INDEX KEY:** 0001780066
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39438
- **FILM NUMBER:** 23504193

**BUSINESS ADDRESS:**
- **STREET 1:** 400 TECHNOLOGY SQUARE
- **STREET 2:** 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
- **BUSINESS PHONE:** 857-201-2700

**MAIL ADDRESS:**
- **STREET 1:** 400 TECHNOLOGY SQUARE
- **STREET 2:** 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Disc Medicine, Inc.
- **CENTRAL INDEX KEY:** 0001816736
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **IRS NUMBER:** 851613057
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 300 ONE KENDALL SQUARE, 3RD FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
- **BUSINESS PHONE:** (617) 401-4400

**MAIL ADDRESS:**
- **STREET 1:** 300 ONE KENDALL SQUARE, 3RD FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Gemini Therapeutics, Inc. /DE
- **DATE OF NAME CHANGE:** 20210209

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** FS Development Corp.
- **DATE OF NAME CHANGE:** 20200702

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

[ ] Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Atlas Venture Fund X, L.P.<br><sub>(Last) (First) (Middle)</sub><br>300 TECHNOLOGY SQUARE, 8TH FLOOR<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02139<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2022-12-29 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Disc Medicine, Inc. [ IRON ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>ATLAS VENTURE ASSOCIATES X, L.P.<br><sub>(Last) (First) (Middle)</sub><br>300 TECHNOLOGY SQUARE, 8TH FLOOR<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02139<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2022-12-29 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Disc Medicine, Inc. [ IRON ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Atlas Venture Associates X, LLC<br><sub>(Last) (First) (Middle)</sub><br>300 TECHNOLOGY SQUARE, 8TH FLOOR<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02139<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2022-12-29 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Disc Medicine, Inc. [ IRON ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Atlas Venture Opportunity Fund I, L.P.<br><sub>(Last) (First) (Middle)</sub><br>300 TECHNOLOGY SQUARE, 8TH FLOOR<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02139<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2022-12-29 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Disc Medicine, Inc. [ IRON ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Atlas Venture Associates Opportunity I, L.P.<br><sub>(Last) (First) (Middle)</sub><br>300 TECHNOLOGY SQUARE, 8TH FLOOR<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02139<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2022-12-29 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Disc Medicine, Inc. [ IRON ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Atlas Venture Associates Opportunity I, LLC<br><sub>(Last) (First) (Middle)</sub><br>300 TECHNOLOGY SQUARE, 8TH FLOOR<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02139<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2022-12-29 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Disc Medicine, Inc. [ IRON ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2022-12-29 |  | J<sup>(1)</sup> |  | 1835799 | A | <sup>(1)(2)</sup> | 2237303 | D<sup>(3)</sup> |  |
| Common Stock | 2022-12-29 |  | J<sup>(1)</sup> |  | 882224 | A | <sup>(1)(2)</sup> | 955156 | I | See Footnote<sup>(4)</sup> |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

---

### Footnotes:

(1) Gemini Therapeutics, Inc. (" Gemini"), and Disc Medicine Opco, Inc. (f/k/a Disc Medicine, Inc.) ("Disc"), entered into an Agreement and Plan of Merger and Reorganization (the "Merger Agreement"), on August 9, 2022, pursuant to which, among other matters, a direct, wholly owned subsidiary of Gemini, Gemstone Merger Sub, Inc. ("Merger Sub"), merged with and into Disc, with Disc surviving as a wholly owned subsidiary of Gemini, and the surviving corporation of the merger, which transaction is referred to herein as the merger. The merger closed on on December 29, 2022. Following the effectiveness of the merger on December 29, 2022, the surviving corporation changed its name from Gemini to Disc Medicine, Inc. (the "Issuer").

(2) (Continued from footnote 1) Upon the closing of the merger, each share of Disc common stock (after giving effect to the conversion of each share of Disc's preferred stock into Disc common stock and including all such shares that are converted into Disc common stock) was converted into the right to receive a number of shares of Gemini common stock equal to an exchange ratio of 0.1096.

(3) These shares are held directly by Atlas Venture Fund X, L.P. ("Atlas X"). Atlas Venture Associates X, L.P. ("Associates X") is the general partner of Atlas X. Atlas Venture Associates X, LLC ("Associates X LLC") is the general partner of Associates X. Each of Associates X and Associates X LLC disclaims Section 16 beneficial ownership of the securities held by Atlas X, except to the extent of its pecuniary interest therein, if any.

(4) These shares are held directly by Atlas Venture Opportunity Fund I, L.P. ("Atlas Opportunity I"). Atlas Venture Associates Opportunity I, L.P. ("Associates I") is the general partner of Atlas Opportunity I. Atlas Venture Associates Opportunity I, LLC ("Associates I LLC") is the general partner of Associates I. Each of Associates I and Associates I LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Opportunity I, except to the extent of its pecuniary interest therein, if any.

**Signature:** Atlas Venture Fund X, L.P., By: Atlas Venture Associates X, L.P., its general partner, By: Atlas Venture Associates X, LLC, its general partner, By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan  
**Date:** 2023-01-03

**Signature:** Atlas Venture Associates X, L.P., By: Atlas Venture Associates X, LLC, its general partner, By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan  
**Date:** 2023-01-03

**Signature:** Atlas Venture Associates X, LLC By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan  
**Date:** 2023-01-03

**Signature:** Atlas Venture Opportunity Fund I, L.P., By: Atlas Venture Associates Opportunity I, L.P., its general partner, By: Atlas Venture Associates Opportunity I, LLC, its general partner, By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan  
**Date:** 2023-01-03

**Signature:** Atlas Venture Associates Opportunity I, L.P., By: Atlas Venture Associates Opportunity I, LLC, its general partner, By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan  
**Date:** 2023-01-03

**Signature:** Atlas Venture Associates Opportunity I, LLC By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan  
**Date:** 2023-01-03

### Remarks:

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**