Wolf-Hirschhorn syndrome is recognized by its clini cal phenotype caused by deletion(s) in the short arm of chromosome 4. The typical phenotype characteristics of WHS are already well known, but rarity of new cases gives the contribution to better understanding of a wide spectrum of possible clinical manifestations. Wolf-Hirsch horn syndrome has a 2:1 predilection for females. Both of the patients reported in this article are females.

Intrauterine growth retardation (IUGR) was detected in both cases. The IUGR of the first patient was detected from the 23rd week of gestation. According to the litera ture [10,11], prenatal chromosomal analysis is indicated in the case of IUGR associated with other ultrasonog-raphically-detected anomalies (heart defects, hypospadia, sceletal anomalies).

Phenotype expression depends on the size of the dele tion of the chromosome [12,13]. Patients with large dele tions of the short arm of chromosome 4 are usually more affected, with severe developmental delay, mental retarda tion, microcephaly, heart defects, midline defects, kidney abnormalities and seizures. Patients with microdeletions have milder phenotypic changes, usually without congen ital malformations, with milder developmental delay, although microcephaly is usually present. Patients with small microdeletions have a mild expression of the dis ease, which consists of typical face appearance, mild mental retardation, mild developmental delay and mild congen ital hypotonia. For precise cytogenetic-morphological correlation, besides conventional chromosomal analysis, molecular probes on apparently normal chromosomes are necessary in some cases, in order to detect submicroscopic deletions [9,12,14].

The facial dysmorphism of both our patients corre sponds roughly to the characteristic description given by most authors [4,5,12]. Both patients were hypotonic, sei zures were registered in the first case. Hypotonia and sei zures were commonly noted by other authors [5,9,13], and cytogenetic disorder was followed by hypotonia and sei zures in approximately 80% of cases.

The first patient did not have a heart septal defect, but the second patient did. According to the literature, septal defects were found in half of the patients [4]. Cleft palate, described in about two-thirds of patients [9], was present in the second patient. As a part of midline defects, the first patient had an anomaly of the cervical spinal column and partial agenesis of the corpus callosum, anomalies which were sporadically described by other authors [4,9].