Editor—Cryptic translocations usually involve the telomeric regions of chromosomes and are not easy to detect by means of conventional cytogenetics.1 2 The published cryptic translocations have been identified through a phenotype corresponding to a chromosome deletion syndrome or as a result of the observation of an anomalous chromosome, in which case they are known as half cryptic translocations because only one of the chromosomes involved can be seen cytogenetically. The presence of satellites at the p or q end of non-acrocentric chromosomes seems to be quite a common phenomenon3 4 and represents a type of half cryptic translocation that signals a rearrangement between the satellited chromosome and one of the acrocentrics.

We describe here a family with a half cryptic translocation detected through a dysmorphic child. The reproductive history of the couple and their family was unremarkable.

The proband was the second child of the couple (daughter 1); the first was a phenotypically normal male and the third was a female with a mildly abnormal phenotype (daughter 2). The third month of gestation was characterised by a threatened miscarriage and the seventh by threatened premature labour. Spontaneous delivery occurred at 41 weeks' of gestation. Apgar scores were 9 and 10 at one and five minutes, respectively. Birth weight was 2770 g (>3rd centile), length 48 cm (3rd centile), and head circumference 30 cm (<3rd centile). A CT scan at birth showed microcephaly without any brain anomalies; the results of cerebral and renal echography were also normal. During the early neonatal period the child had feeding problems and her growth was retarded despite artificial feeding. She experienced her first febrile seizure at the age of 11 months, which was followed by a further five episodes with hyperpyrexia over the next five years. Antiepileptic therapy with phenobarbital was …