OMIM ID:
Neu-Laxova Syndrome 1
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
The globes are prominent, an appearance that is exaggerated sometimes by absence of the eyelids or ectropion. The lashes may be absent in other patients. Cloudy corneas and cataracts have been described.
Systemic Features
This is a lethal dysplasia-malformation syndrome in which some infants are stillborn while others do not live beyond a few days. The placenta is often small and the umbilical cord is short. Decreased fetal movements and polyhydramnios are often noted. Microcephaly can be striking at birth but there is overall intrauterine growth retardation. The skin is ichthyotic and dysplastic containing excess fatty tissue beneath the epidermis. Digits are often small and may be fused (syndactyly). There is generalized edema with ‘puffiness’ of the hands and feet. The lungs are frequently underdeveloped and cardiac defects such as septal openings, patent ductus arteriosus and transposition of great vessels are common. Males often have cryptorchidism while females have a bifid uterus and renal dysgenesis has been reported.
The face is dysmorphic with prominent globes (in spite of microphthalmia), the ears are large and malformed, the forehead is sloping, the nose is flattened and the jaw is small. Some infants have a cleft lip and palate while the mouth is round and gaping. The neck is usually short.
Severe brain malformations such as lissencephaly, cerebellar hypoplasia, and dysgenesis/agenesis of the corpus callosum are frequently present.
Genetics
Inheritance
This is an autosomal recessive disorder secondary to mutations in the PHGDH gene (1p12).
This condition has some clinical overlap with Neu-Laxova syndrome 2 (616038) but the latter is less severe and is caused by a different mutation.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.