Lenz microphthalmia syndrome is a very rare inherited disorder characterized by abnormal smallness of one or both eyes (
microphthalmos) sometimes with droopy eyelids (
blepharoptosis), resulting in visual impairment or blindness. Eye problems may include
coloboma
A coloboma (from the Greek , meaning defect) is a hole in one of the structures of the eye, such as the iris, retina, choroid, or optic disc. The hole is present from birth and can be caused when a gap called the choroid fissure, which is presen ...
, microcornea, and
glaucoma
Glaucoma is a group of eye diseases that result in damage to the optic nerve (or retina) and cause vision loss. The most common type is open-angle (wide angle, chronic simple) glaucoma, in which the drainage angle for fluid within the eye rem ...
. Some affected infants may have complete absence of the eyes (
anophthalmia
Anophthalmia, (Greek: ἀνόφθαλμος, "without eye"), is the medical term for the absence of one or both eyes. Both the globe (human eye) and the ocular tissue are missing from the orbit. The absence of the eye will cause a small bony orbi ...
). Most affected infants have
developmental delay
Global developmental delay is an umbrella term used when children are significantly delayed in their cognitive and physical development. It can be diagnosed when a child is delayed in one or more milestones, categorised into motor skills, speech ...
and
intellectual disability
Intellectual disability (ID), also known as general learning disability in the United Kingdom and formerly mental retardation, Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010). is a generalized neurodevelopmental disorder characterized by signif ...
, ranging from mild to severe. Other physical abnormalities associated with this disorder can include an unusually small head (
microcephaly
Microcephaly (from New Latin ''microcephalia'', from Ancient Greek μικρός ''mikrós'' "small" and κεφαλή ''kephalé'' "head") is a medical condition involving a smaller-than-normal head. Microcephaly may be present at birth or it ...
), and malformations of the teeth, ears, fingers or toes, skeleton, and genitourinary system. The range and severity of findings vary from case to case. Formal diagnosis criteria do not exist.
Lenz microphthalmia syndrome is also known as LMS, Lenz syndrome, Lenz dysplasia, Lenz dysmorphogenetic syndrome, or microphthalmia with multiple associated anomalies (MAA: OMIM 309800). It is named after
Widukind Lenz, a German geneticist and dysmorphologist.
Genetics
Lenz microphthalmia syndrome is inherited as an
X-linked recessive
X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be always expressed in males (who are necessarily homozygous for the gene mutation because they have one X and one Y ...
genetic trait and is fully expressed in males only. Females who carry one copy of the disease gene (
heterozygote
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism.
Mo ...
s) may exhibit some of the symptoms associated with the disorder, such as an abnormally small head (microcephaly), short stature, or malformations of the fingers or toes. Molecular genetic testing of
BCOR (MCOPS2 locus), the only gene known to be associated with Lenz microphthalmia syndrome, is available on a clinical basis. One additional locus on the X chromosome (MCOPS1) is known to be associated with LMS.
Diagnosis
Differential diagnosis
A somewhat similar X-linked syndrome of microphthalmia, called
oculofaciocardiodental syndrome (OFCD) is associated with mutations in BCOR. OFCD syndrome is inherited in an X-linked dominant pattern with male lethality.
Management
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References
Lenz Microphthalmia Syndrome Syndromes affecting the eye
Syndromes affecting head size