Primeiro registro do select nao aparece

Question

Boa Noite

estou tentando popular um grid e tenho 3 registros no banco , mas quando exibo o form so aparecem 2 registros , percebi que é o primeiro que nao aparece ..

Alguem ja teve esse problema , abaixo segue o codigo e estou fazendo em windows forms com C#

Obrigado

// DataSet dt = new DataSet();
      DataTable dt = new DataTable();
      string Constr = @"Data Source=.\sqlexpress;AttachDbFilename=C:\Cobranca\Dados\Juridico.mdf;Integrated Security=True";
      ///  string Constr = @"Data Source=htw\sqlexpress;AttachDbFilename=C:\Cobranca2\Dados\Juridico.mdf;Integrated Security=True";
      SqlConnection Conn = new SqlConnection(Constr);
      SqlCommand cmd = new SqlCommand("select IdEndereco, logradouro, bairro, cidade, UF, CEP from Enderecos order by Logradouro ", Conn);
      Conn.Open();
      SqlDataReader dtr = cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
      dtr.Read();
      dt.Load(dtr);


        dataGridView1.DataSource = dt;
        dataGridView1.Sort(dataGridView1.Columns[1], System.ComponentModel.ListSortDirection.Ascending);
        dataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
        dataGridView1.AlternatingRowsDefaultCellStyle.BackColor = Color.LightGray;
        DataGridViewCellStyle style = new DataGridViewCellStyle();
        dataGridView1.Columns[0].HeaderText = "CÓDIGO";
        dataGridView1.Columns[1].HeaderText = "LOGRADOURO";
        dataGridView1.Columns[2].HeaderText = "BAIRRO";
        dataGridView1.Columns[3].HeaderText = "CIDADE";
        dataGridView1.Columns[4].HeaderText = "UF";
        dataGridView1.Columns[5].HeaderText = "CEP";
        style.Alignment = DataGridViewContentAlignment.MiddleCenter;
        style.Font = new Font("Arial", 12, FontStyle.Bold, GraphicsUnit.Pixel);
        dataGridView1.Columns[0].HeaderCell.Style = style;
        dataGridView1.Columns[1].HeaderCell.Style = style;
        dataGridView1.Columns[2].HeaderCell.Style = style;
        dataGridView1.Columns[3].HeaderCell.Style = style;
        dataGridView1.Columns[4].HeaderCell.Style = style;
        dataGridView1.Columns[5].HeaderCell.Style = style;
        dataGridView1.Columns[0].Width = 50;
        dataGridView1.Columns[1].Width = 300;
        dataGridView1.Columns[2].Width = 200;
        dataGridView1.Columns[3].Width = 200;
        dataGridView1.Columns[4].Width = 50;
        dataGridView1.Columns[5].Width = 90;
        textBox1.Focus();