1. Editorial help

   EditorialNotes Pages: 275 - 275

2. Further studies on compartmentalisation of DNA-topoisomerase I in Fanconi anemia tissue

   • E. Wunder

   Original Investigations Pages: 276 - 281

3. Localisation of genetic markers and orientation of the linkage group on chromosome 19

   • J. D. Brook
   • D. J. Shaw
   • P. S. Harper

   Original Investigations Pages: 282 - 285

4. The isolation of a genomic clone containing the apolipoprotein CII gene and the detection of linkage disequilibrium between two common DNA polymorphisms around the gene

   • S. C. Wallis
   • J. A. Donald
   • S. E. Humphries

   Original Investigations Pages: 286 - 289

5. Nonrandom distribution of methotrexate-induced aberrations on human chromosomes. Detection of further folic acid sensitive fragile sites

   • G. Barbi
   • P. Steinbach
   • W. Vogel

   Original Investigations Pages: 290 - 294

6. Spindle microtubular dysfunction in mothers of Down syndrome children

   • Judith Helen Ford

   Original Investigations Pages: 295 - 298

7. Intercellular NOR-AG variability in man

   • O. A. Sozansky
   • A. F. Zakharov
   • V. A. Benjush

   Original Investigations Pages: 299 - 302

8. X-linked agammaglobulinemia and the red blood cell determinants Xg and 12E7 are not closely linked

   • E. J. B. M. Mensink
   • J. D. L. Schot
   • R. K. B. Schuurman

   Original Investigations Pages: 303 - 309

9. Prenatal detection of an unstable ring 21 chromosome

   • Gail Stetten
   • Bernadette Sroka
   • Corinne D. Boehm

   Original Investigations Pages: 310 - 313

10. Population studies on human phosphoglucomutase-1 thermostability polymorphism

    • R. Scozzari
    • C. Iodice
    • A. S. Santachiara-Benerecetti

    Original Investigations Pages: 314 - 317

11. α-Thalassemia among sickle cell anemia patients in various African populations

    • J. Pagnier
    • O. Dunda-Belkhodja
    • D. Labie

    Original Investigations Pages: 318 - 319

12. Aspects of sickle cell gene in Saudi Arabia—interaction with glucose-6-phosphate dehydrogenase deficiency

    • M. A. F. El-Hazmi
    • A. S. Warsy

    Original Investigations Pages: 320 - 323

13. Mitochondrial DNA polymorphism in Japanese

    • Satoshi Horai
    • Takashi Gojobori
    • Ei Matsunaga

    Original Investigations Pages: 324 - 332

14. Conservation of the human COL1A1-TK-GAA synteny and homoeologous assignment in the African green monkey and the baboon (Cercopithecoidae)

    • Nicole Créau-Goldberg
    • Catherine Turleau
    • Jean de Grouchy

    Original Investigations Pages: 333 - 336

15. Fetal mortality at the time of chorionic villi sampling

    • Abby Lippman
    • Michel J. J. Vekemans
    • Tracy B. Perry

    Short Communications Pages: 337 - 339

16. Homozygosity for fragile site at 17p12 in a 28-year-old healthy man

    • Viliam Izakovič

    Short Communications Pages: 340 - 341

17. Hyalinosis cutis et mucosae in siblings

    • E. Haneke
    • O. P. Hornstein
    • W. Steiner

    Clinical Case Reports Pages: 342 - 345

18. Verification of Lyon's hypothesis in fragile X carriers

    • Miguel A. De Arce

    Letters to the Editors Pages: 346 - 347

19. Reply to Hecht and Hecht

    • J. M. García-Sagredo
    • C. San Román

    Letters to the Editors Pages: 348 - 348

20. Genetic aspects of hemifacial microsomia

    • J. M. Connor
    • C. Fernandez

    Letters to the Editors Pages: 349 - 349

21. Yqs in an American family of Scottish descent

    • Kazuso Iinuma
    • Wladimir Wertelecki
    • V. G. Dev

    Letters to the Editors Pages: 350 - 350

22. Confirmation of the assignment of the gene coding for the BA-2 antigen to human chromosome 12

    • J. J. M. van Dongen
    • I. L. M. Tettero
    • A. Hagemeijer

    Letters to the Editors Pages: 351 - 352

23. Announcements

    Announcement Pages: 353 - 353

24. Announcements

    Announcement Pages: 354 - 354

25. Announcements

    Announcement Pages: 355 - 355