The recently described classical case of dyskeratosis congenita (DC)(1) lacked information as to whether the patient had features of immunodeficiency. The immune abnormalities described in X-linked DC include hypogammaglobulinemia (low IgM levels), severe B cell lymphopenia, low numbers of T cells, increased rate of apoptosis and marked reduction in cellular proliferation in short-term cultures(2,3). DC can occasionally present as T+B-NK- severe combined immunodeficiency (complete absence of B and NK or natural killer cells) in the most severe form, referred to as Hoyeraal-Hreidarsson synd-rome(4). Recurrent infections and deaths secondary to Pnemocystis pneumonia and cytomegalovirus infections have been reported. Osteoporosis, liver and lung fibrosis are also seen and hence use of busulfan or excessive radiation are considered to be relative contraindications.

In situ hybridization techniques can detect short telomeres (cause of early ageing) even in clinically silent disease (disease anticipation)(5). X-linked DC is one of the conditions in the growing list of disorders of ribosome biogenesis and mutation testing (DKC1 gene mutations in X-linked recessive DC) can be done for confirmation, but is only available in few referral centres. DC should be suspected in children presenting with aplastic anaemia and multi-organ problems, and clinicians should investigate for immunodeficiency (by measuring antibody levels and enumeration of lymphocyte subsets), so that recurrent infections are prevented before bone marrow transplantation.

1. Gupta V, Bhatia BD. Dyskeratosis congenita. Indian Pediatr 2008; 45: 936.

2. Knudson M, Kulkarni S, Ballas ZK, Bessler M, Goldman F. Association of immune abnormalities with telomere shortening in autosomal-dominant dyskeratosis congenita. Blood 2005; 105: 682-688.

3. Lee BW, Yap HK, Quah TC, Chong A, Seah CC. T cell immunodeficiency in dyskeratosis congenita. Arch Dis Child 1992; 67: 524-526.

4. Cossu F, Vulliamy TJ, Marrone A, Badiali M, Cao A, Dokal I. A novel DKC1 mutation, severe combined immunodeficiency (T+B-NK- SCID) and bone marrow transplantation in an infant with Hoyeraal-Hreidarsson syndrome. Br J Haematol 2002; 119: 765-768.