When examining sufficiency of disclosure, the boards have to be satisfied, firstly, that the patent specification places the skilled person in possession of at least one way of putting the claimed invention into practice, and secondly, that the skilled person can put the invention into practice over the whole scope of the claim (see e.g. T 792/00, T 811/01, T 1241/03, T 364/06; see also T 1727/12, "Biogen sufficiency"). The scope of the patent should be justified by the technical contribution to the art (T 612/92). The necessary extent of disclosure is assessed on a case-by-case basis having regard to the essence of the invention (T 694/92, OJ 1997, 408).

In T 292/85 (OJ 1989, 275) the board stated that an invention is regarded as sufficiently disclosed if at least one way is clearly indicated enabling the skilled person to carry out the invention. The invention at issue concerned a recombinant plasmid comprising a homologous regulon, heterologous DNA and one or more termination codons for expression in bacteria of a functional heterologous polypeptide in recoverable form. The application was refused by the examining division on the grounds that not all embodiments falling within the broad functional wording of the claims were available. The board, however, held that the non-availability of some particular variants was immaterial as long as there were suitable variants known which provided the same effect.

Similarly, in T 386/94 (OJ 1996, 658) the patent specification provided a technically detailed example for the expression of preprochymosin and its maturation forms in E. coli. It suggested the possibility of expressing these proteins in micro-organisms in general. The board held that the invention was sufficiently disclosed because one way to carry out the invention was clearly indicated and the state of the art contained no evidence that foreign genes could not be expressed in organisms other than E. coli. The principles set out in T 292/85 (OJ 1989, 275) were also applied in T 984/00 (where the invention lay in the use of the T-region of the Agrobacterium without the genes of the T-region of wild type Ti-plasmids to avoid the deleterious effects of these genes on the target plant) and in T 309/06 (where the appellant had disclosed a novel group of enzymes characterised by useful properties and the board allowed the appellant to claim the enzymes independently of their origin).

As for the amount of detail needed for a sufficient disclosure, this depends on the correlation of the facts of the case to certain general parameters, such as the character of the technical field and the average amount of effort necessary to put into practice a certain written disclosure in that technical field, the time when the disclosure was presented to the public and the corresponding common general knowledge, and the amount of reliable technical details disclosed in a document (see T 158/91; T 694/92, OJ 1997, 408; T 639/95; T 36/00; T 1466/05; T 2220/14).