Amish lethal microcephaly

General Information (adopted from Orphanet):

Synonyms, Signs: THIAMINE METABOLISM DYSFUNCTION SYNDROME 3 (MICROCEPHALY TYPE)
AMISH LETHAL MICROCEPHALY
MCPHA
THMD3
Number of Symptoms 45
OrphanetNr: 99742
OMIM Id: 607196
ICD-10: Q02
UMLs:
MeSH:
MedDRA:
Snomed:

Prevalence, inheritance and age of onset:

Prevalence: No data available.
Inheritance: Autosomal recessive
[Orphanet]
Age of onset: Neonatal
Infancy
[Orphanet]

Disease classification (adopted from Orphanet):

Parent Diseases: Syndrome with microcephaly as major feature
 -Rare developmental defect during embryogenesis
 -Rare genetic disease
 -Rare neurologic disease

Symptom Information: Sort by abundance 

1
(HPO:0001992) Organic aciduria Very frequent [Orphanet] 28 / 7739
2
(HPO:0000253) Progressive microcephaly 37 / 7739
3
(HPO:0004331) Decreased skull ossification Occasional [Orphanet] 31 / 7739
4
(HPO:0100736) Abnormality of the soft palate Occasional [Orphanet] 6 / 7739
5
(HPO:0000277) Abnormality of the mandible Very frequent [Orphanet] 394 / 7739
6
(HPO:0000347) Micrognathia 426 / 7739
7
(HPO:0000252) Microcephaly Very frequent [Orphanet] 832 / 7739
8
(HPO:0000340) Sloping forehead Very frequent [Orphanet] 86 / 7739
9
(HPO:0001250) Seizures Occasional [Orphanet] 1245 / 7739
10
(HPO:0000737) Irritability 93 / 7739
11
(HPO:0100851) Abnormal emotion/affect behavior Very frequent [Orphanet] 85 / 7739
12
(HPO:0001276) Hypertonia Frequent [Orphanet] 317 / 7739
13
(HPO:0002509) Limb hypertonia 13 / 7739
14
(HPO:0001371) Flexion contracture 220 / 7739
15
(HPO:0001387) Joint stiffness Occasional [Orphanet] 322 / 7739
16
(HPO:0004349) Reduced bone mineral density Frequent [Orphanet] 165 / 7739
17
(HPO:0002414) Spina bifida Frequent [Orphanet] 47 / 7739
18
(HPO:0001557) Prenatal movement abnormality Occasional [Orphanet] 16 / 7739
19
(HPO:0002240) Hepatomegaly Occasional [Orphanet] 467 / 7739
20
(HPO:0004325) Decreased body weight Very frequent [Orphanet] 492 / 7739
21
(HPO:0003128) Lactic acidosis 116 / 7739
22
(HPO:0004360) Abnormality of acid-base homeostasis Very frequent [Orphanet] 5 / 7739
23
(HPO:0001252) Muscular hypotonia Frequent [Orphanet] 990 / 7739
24
(HPO:0008936) Muscular hypotonia of the trunk 77 / 7739
25
(HPO:0000007) Autosomal recessive inheritance 2538 / 7739
26
(HPO:0003577) Congenital onset 133 / 7739
27
(HPO:0007370) Aplasia/Hypoplasia of the corpus callosum Frequent [Orphanet] 180 / 7739
28
(OMIM) Increased urinary 2-ketoglutarate (variable) 1 / 7739
29
(OMIM) Increased urinary lactate 4 / 7739
30
(OMIM) Absence of anterior and posterior fontanelles 1 / 7739
31
(HPO:0002536) Abnormal cortical gyration Frequent [Orphanet] 72 / 7739
32
(HPO:0012795) Abnormality of the optic disc Very frequent [Orphanet] 187 / 7739
33
(OMIM) No psychomotor development 1 / 7739
34
(OMIM) Lactic acidosis during infection 1 / 7739
35
(OMIM) Hepatomegaly associated with infection 1 / 7739
36
(OMIM) Microcephaly, extreme 1 / 7739
37
(HPO:0001321) Cerebellar hypoplasia 114 / 7739
38
(OMIM) Nearly absent cranial vault 1 / 7739
39
(HPO:0012758) Neurodevelopmental delay Very frequent [Orphanet] 949 / 7739
40
(OMIM) Immature brain with no gyral development 1 / 7739
41
(HPO:0002334) Abnormality of the cerebellar vermis Very frequent [Orphanet] 137 / 7739
42
(HPO:0001522) Death in infancy Very frequent [Orphanet] 275 / 7739
43
(OMIM) Hypoplastic pons 1 / 7739
44
(HPO:0002119) Ventriculomegaly Frequent [Orphanet] 253 / 7739
45
(HPO:0001338) Partial agenesis of the corpus callosum 22 / 7739

Associated genes:

ClinVar (via SNiPA)

Gene symbol Variation Clinical significance Reference

Additional Information:

Description: (OMIM) Amish type microcephaly is a severe autosomal recessive metabolic disorder characterized by severe microcephaly apparent at birth, profoundly delayed psychomotor development, brain malformations, and episodic encephalopathy associated with lactic acidosis and alpha-ketoglutaric aciduria (summary by Kelley et al., ...
Clinical Description OMIM Kelley et al. (2002) described a metabolic disorder among the Old Order Amish of Lancaster County, Pennsylvania, characterized by severe congenital microcephaly, death within the first year, and severe 2-ketoglutaric aciduria. The disorder segregated as an autosomal recessive ...
Molecular genetics OMIM Rosenberg et al. (2002) identified a list of positional candidate genes, comprising 7 full-length cDNAs, 3 EST clusters, and 11 predicted genes. The authors reasoned that because alpha-ketoglutarate is a component of the Krebs cycle, the alpha-ketoglutarate abnormality ...
Diagnosis GeneReviews The major clinical finding in individuals with Amish lethal microcephaly (MCPHA) is severe microcephaly present at birth [Kelley et al 2002]. Occipitofrontal circumference (OFC) is typically six to 12 standard deviations below the mean. ...
Clinical Description GeneReviews Amish lethal microcephaly (MCPHA) is a distinct disorder with little variability in its presentation, at least among the Old Order Amish from Lancaster County, Pennsylvania [Kelley et al 2002]. Affected infants have severe microcephaly at birth. The cranial vault is extremely underdeveloped as a result of the small brain size. Anterior and posterior fontanels are closed, and ridging from premature sutural fusion may be evident. The facial features are distorted as a result of the profound microcephaly. The only non-CNS physical anomaly is moderate micrognathia. Mild hepatomegaly has been observed in several affected individuals, usually during acute illnesses associated with metabolic acidosis....
Differential Diagnosis GeneReviews Microcephaly has a wide variety of causative factors. It can be syndromic or isolated, environmental or genetic, congenital or acquired [Battaglia & Carey 2003]. A metabolic screen (including urine organic acids, plasma amino acids, lactate, pyruvate, and electrolytes) is indicated for all children with congenital microcephaly. Further specific evaluations are performed as indicated based on the results of this screen....
Management GeneReviews To establish the extent of disease in an individual diagnosed with Amish lethal microcephaly (MCPHA), appropriate imaging studies should be performed. Refer to general references on microcephaly for guidance; no recommendations are specific to MCPHA....
Molecular genetics GeneReviews Information in the Molecular Genetics and OMIM tables may differ from that elsewhere in the GeneReview: tables may contain more recent information. —ED....