diff --git a/api/sda/sda.go b/api/sda/sda.go
index c86731f..2982ffc 100644
--- a/api/sda/sda.go
+++ b/api/sda/sda.go
@@ -207,7 +207,7 @@ func Download(c *gin.Context) {
 	}
 
 	// Stitch file and prepare it for streaming
-	fileStream, err := stitchFile(fileDetails.Header, file, coordinates)
+	fileStream, err := stitchFile(fileDetails.Header, file)
 	if err != nil {
 		log.Errorf("could not prepare file for streaming, %s", err)
 		c.String(http.StatusInternalServerError, "file stream error")
@@ -215,22 +215,98 @@ func Download(c *gin.Context) {
 		return
 	}
 
-	sendStream(c.Writer, fileStream)
+	// Get query params
+	qStart := r.URL.Query().Get("startCoordinate")
+	qEnd := r.URL.Query().Get("endCoordinate")
+
+	// Parse and verify coordinates are valid
+	if len(qStart) > 0 && len(qEnd) > 0 {
+		start, err := strconv.ParseUint(qStart, 10, 64)
+		if err != nil {
+			log.Errorf("failed to convert start coordinate %d to integer, %s", start, err)
+
+			return nil, errors.New("startCoordinate must be an integer")
+		}
+		end, err := strconv.ParseUint(qEnd, 10, 64)
+		if err != nil {
+			log.Errorf("failed to convert end coordinate %d to integer, %s", end, err)
+
+			return nil, errors.New("endCoordinate must be an integer")
+		}
+		if end < start {
+			log.Errorf("endCoordinate=%d must be greater than startCoordinate=%d", end, start)
+
+			return nil, errors.New("endCoordinate must be greater than startCoordinate")
+		}
+
+		if start != 0 {
+			// We don't want to read from start, skip ahead to where we should be
+			if _, err := reader.Seek(start, 0); err != nil {
+				return err
+			}
+		}
+
+		// Calculate how much we should read (if given)
+		togo := end - start
+
+		buf := make([]byte, 4096)
+
+		// Loop until we've read what we should (if no/faulty end given, that's EOF)
+		for end == 0 || togo > 0 {
+			rbuf := buf[:]
+
+			if end != 0 && togo < 4096 {
+				// If we don't want to read as much as 4096 bytes
+				rbuf = buf[:togo]
+			}
+			r, err := fileStream.Read(rbuf)
+			togo -= int64(r)
+
+			// Nothing more to read?
+			if err == io.EOF && r == 0 {
+				// Fall out without error if we had EOF (if we got any data, do one
+				// more lap in the loop)
+				return nil
+			}
+
+			if err != nil && err != io.EOF {
+				// An error we want to signal?
+				return err
+			}
+
+			wbuf := rbuf[:r]
+			for len(wbuf) > 0 {
+				// Loop until we've written all that we could read,
+				// fall out on error
+				sendStream(c.Writer, wbuf)
+
+				if err != nil {
+					return err
+				}
+				wbuf = wbuf[w:]
+			}
+		}
+
+	} else {
+		return
+	}
+
 }
 
 // stitchFile stitches the header and file body together for Crypt4GHReader
 // and returns a streamable Reader
-var stitchFile = func(header []byte, file io.ReadCloser, coordinates *headers.DataEditListHeaderPacket) (*streaming.Crypt4GHReader, error) {
+var stitchFile = func(header []byte, file io.ReadCloser) (*streaming.Crypt4GHReader, error) {
 	log.Debugf("stitching header to file %s for streaming", file)
 	// Stitch header and file body together
 	hr := bytes.NewReader(header)
 	mr := io.MultiReader(hr, file)
-	c4ghr, err := streaming.NewCrypt4GHReader(mr, *config.Config.App.Crypt4GHKey, coordinates)
+	c4ghr, err := streaming.NewCrypt4GHReader(mr, *config.Config.App.Crypt4GHKey, nil)
 	if err != nil {
 		log.Errorf("failed to create Crypt4GH stream reader, %v", err)
 
 		return nil, err
 	}
+	defer c4ghr.Close()
 	log.Debugf("file stream for %s constructed", file)
 
 	return c4ghr, nil