Editor—Nijmegen breakage syndrome (NBS) (OMIM 251260) is a rare autosomal recessive condition. The major manifestations include microcephaly, a distinct facial appearance, growth retardation, recurring infections owing to combined immunodeficiency, spontaneous chromosomal instability (with characteristic rearrangements of chromosomes 7 and 14), hypersensitivity to ionising radiation, and a very high predisposition to lymphoid malignancy. The immunological, cytogenetic, and cell biological findings are very similar to those in ataxia telangiectasia (AT); however, NBS patients lack the neurocutaneous manifestations of AT, as well as a raised serum α-fetoprotein (AFP).1-3Recently, the gene mutated in NBS has been cloned. TheNBS1 gene is located on chromosome 8q21 and encodes a protein called nibrin, a member of the hRad50/hMre11 protein complex involved in DNA double strand break processing.4 ,5 NBS is quite a rare disease with about 80 patients ascertained world wide, including 50 Polish. The vast majority of NBS patients are of Slavic origin and carry a common founder mutation 657del5 in exon 6.4

We report on a Polish patient with Nijmegen breakage syndrome presenting an atypical clinical picture with the absence of microcephaly and the presence of a congenital heart defect and preaxial polydactyly. To the best of our knowledge, no NBS patient without microcephaly or with congenital cardiac disease has ever been reported and preaxial polydactyly has been observed in only two other cases.3 The proband, a girl, was born at term by spontaneous vertex delivery after an uneventful pregnancy. Birth weight was 3500 g, length 55 cm, occipitofrontal circumference (OFC) 35.5 cm, and chest circumference 33 cm, all above the 50th centile. Apgar score was 9 at one minute. Clinical investigation at birth showed preaxial polydactyly of the right hand, which has been surgically corrected. No other malformations were noted at that time. She was …