diff --git a/R/utils.R b/R/utils.R
index 560d527..43ae0bd 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -441,15 +441,29 @@ trans_seq_rev<- function(unit = c("Mb", "kb", "bp")){
     function(x) {paste(x, unit)}
 }
 
-scale_x_sequnit <- function(unit = c("Mb", "kb", "bp"), append = NULL){
+scale_x_sequnit <- function(unit = c("Mb", "kb", "bp"), append = NULL, ...){
   unit <- match.arg(unit)
-  if(is.null(append)){
-      scale_x_continuous(breaks = trans_breaks(trans_seq(unit),
-                             trans_seq_rev(unit)),
-                         labels = trans_format(trans_seq_format(unit), math_format(.x)))
-  }else{
+  check_args <- function() {
+    kwargs <- names(list(...))
+    if (is.null(append)) {
+      if (any(c("breaks", "labels") %in% kwargs))
+        stop("scale_x_sequnit already sets breaks and labels arguments when 'append' is set.")
+    } else {
       stopifnot(is.character(append))
-      scale_x_continuous(labels = trans_format(.append_unit(append), math_format(.x)))
+      if ("labels" %in% names(list(...)))
+        stop("scale_x_sequnit already sets 'labels' argument.")
+    }
+  }
+  check_args()
+  if(is.null(append)){
+    scale_x_continuous(
+      breaks = trans_breaks(trans_seq(unit), trans_seq_rev(unit)),
+      labels = trans_format(trans_seq_format(unit), math_format(.x)),
+      ...)
+  } else {
+    scale_x_continuous(
+      labels = trans_format(.append_unit(append), math_format(.x)),
+      ...)
   }
 }
 
diff --git a/man/scale_x_sequnit.Rd b/man/scale_x_sequnit.Rd
index 813c69f..878674e 100644
--- a/man/scale_x_sequnit.Rd
+++ b/man/scale_x_sequnit.Rd
@@ -5,17 +5,22 @@
   scale x by unit 'Mb','kb', 'bp'.
 }
 \usage{
-scale_x_sequnit(unit = c("Mb", "kb", "bp"), append = NULL)
+scale_x_sequnit(unit = c("Mb", "kb", "bp"), append = NULL, ...)
 }
 \arguments{
   \item{unit}{
-    unit to scale x. Default is Mb. 
+    unit to scale x. Default is Mb.
   }
   \item{append}{
-    default \code{NULL}. If pass a character, it disalbe unit and arbitrarily append a
-    text behind the original x scale numbers. 
+    default \code{NULL}. If pass a character, it disable unit and arbitrarily append a
+    text behind the original x scale numbers.
+  }
+  \item{...}{
+    arguments to pass to \code{scale_x_continuous}.
+    Note that \code{scale_x_sequnit} sets breaks and labels
+    automatically, so arguments \code{breaks} and \code{labels} cannot
+    be passed (\code{breaks} can if \code{append} is not set).
   }
-
 }
 \value{
   'position_c'
@@ -30,4 +35,4 @@ p + scale_x_sequnit("kb")
 p + scale_x_sequnit("bp")
 }
 \author{Tengfei Yin}
-
+\author{samuel barreto}