Kavaslar et al. (2000) reported a large consanguineous Anatolian (Turkish) family with children who had the unusual association of microcephaly and hydranencephaly. In addition, the affected children had severe mental and motor retardation, very small body size, and ... Kavaslar et al. (2000) reported a large consanguineous Anatolian (Turkish) family with children who had the unusual association of microcephaly and hydranencephaly. In addition, the affected children had severe mental and motor retardation, very small body size, and very small occipitofrontal circumference (OFC). The youngest patient, 4.5 years of age at the time of study, had a height corresponding to a sex mean of 7 months, weight to 1 month, and OFC to prenatal. Alexander et al. (1995) reported 2 female sibs with fetal brain disruption sequence. Clinical findings included large size at birth with a disproportionately small head circumference and scalp rugae. The degree of microcephaly became more marked with time. Cranial CT scan in both infants revealed gross dilation of the ventricles, almost complete absence of the cerebral hemispheres with a well-formed falx, and a small cerebellum. Elevated semiquantitative mucopolysaccharide levels were consistently obtained from both children, and high resolution electrophoresis revealed an unidentified metabolite and a pattern not consistent with any known mucopolysaccharidosis. Alexander et al. (1995) proposed that accumulation of a neurotoxic metabolite might be responsible for the disease phenotype. Schram et al. (2004) reported 2 sibships with fetal brain degeneration resembling fetal brain disruption sequence: 2 brothers in a Hindu family from Suriname, and a Dutch brother and sister. All of the children had low birth weight, microcephaly, overlapping sutures, and scalp rugae. CT scans of their brains showed severely underdeveloped cerebral hemispheres surrounded by a large amount of cerebrospinal fluid. The authors noted that true hydranencephaly was not present in these cases, but questioned whether a strict delineation between hydranencephaly and fetal brain disruption sequence was justified. Schram et al. (2004) also commented that in cases of sib recurrence, the term 'fetal brain disruption sequence' should be avoided since a disruption sequence indicates an exogenous, sporadic cause of the disorder.